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1: Computer Audio Asylum, RE: Strange............................. (0.00)
Posted by John Swenson on 2014-07-21, 15:49:04 (192.19.225.250)
The Surface (and some of the Asus tablets) use an ARM processor, not an x86 processor so they cannot run normal windows binaries, it's a completely different processor architecture and instruction set .......
2: Computer Audio Asylum, RE: Can someone explain Gordon Rankin's vague response here.. (0.00)
Posted by John Swenson on 2014-02-26, 21:48:13 (24.6.202.157)
It's just what it says. All DAC chips that say the take DSD actually use a multilevel output stage fed by a DSM. They somehow convert the DSD signal (two level format) into something they can feed thr .......
3: Computer Audio Asylum, RE: Power Line Noise Coupling to Amplifiers (0.00)
Posted by John Swenson on 2014-01-16, 13:05:57 (192.19.225.250)
Cheap isolation transformers are actually one of the few options that work pretty well. The cheap ones have high loss magnetic circuits which damp resonances, this significantly cuts down on what gets .......
4: Computer Audio Asylum, RE: FLAC files are decoded on the server, before being played back on SB Touch? (0.00)
Posted by John Swenson on 2014-01-14, 16:55:52 (192.19.225.250)
The SBT can decode FLAC. From the server you have a choice, you can send either FLAC stream or PCM stream. (you have the same choice for other formats as well, for example you can send a WAV file as a .......
5: Computer Audio Asylum, RE: Power Line Noise Coupling to Amplifiers (0.00)
Posted by John Swenson on 2014-01-14, 16:43:27 (192.19.225.250)
On the subject of 30KHz to 300KHz noise Thorsten is right. Several years ago I did a fairly extensive test of power supplies in all kinds of audio equipment, what I found was that for most gear noise .......
6: Computer Audio Asylum, RE: Unobtainium (0.00)
Posted by John Swenson on 2013-11-13, 12:32:20 (192.19.224.250)
Hi Tony, this is fairly easy to do. The expensive part is the power supplies. It might be cheaper to go with LiPO batteries for each section. It wouldn't necessarily require separate boxes, a single .......
7: Computer Audio Asylum, RE: i think I finally understand it now... [revised] (0.00)
Posted by John Swenson on 2013-11-13, 12:02:17 (192.19.224.250)
I don't think your description is quite correct. When you feed a pico regulator from a 12V linear supply the 12V goes straight through. The DC/DC converters in the pico are only for the 5V and 3.3V ra .......
8: Computer Audio Asylum, RE: See his response to my questions below... (0.00)
Posted by John Swenson on 2013-11-02, 23:04:36 (71.37.214.148)
The standard XMOS USB audio package is UAC2 compliant which should only need a driver for Windows. The "XMOS chip" is a processor, not a USB specific receiver chip. XMOS provides a USB audio code pac .......
9: Computer Audio Asylum, RE: Some questions about usb cables (0.00)
Posted by John Swenson on 2013-10-18, 10:52:20 (69.170.105.138)
USB devices will pull up either the D+ or D- wire to signal the host what speed they run at. According to the spec that pull up is not supposed to happen until Vbus is high. So theoretically you need .......
10: Computer Audio Asylum, Interface "isolation" (0.00)
Posted by John Swenson on 2013-10-16, 18:44:46 (216.110.95.123)
There have recently been a number of threads discussing interface isolation, there seems to be some significant misunderstanding of different types of isolation and what can and cannot be done. I tho .......
11: Computer Audio Asylum, RE: Ess9018 Kit with Measurements for diyers (0.00)
Posted by John Swenson on 2013-10-02, 05:33:32 (216.161.175.55)
I have not heard this but just by looking at the pictures it is not a particularly good implementation. They say it is a flagship design, but I don't see anything close to being flagship about this. T .......
12: Computer Audio Asylum, RE: Is firewire still better than usb for audio ? (0.00)
Posted by John Swenson on 2013-09-24, 15:18:07 (192.19.225.100)
I did read a statement a while back from the person in charge of the group that developes such things at MS, he considers the only people that will ever want a UAC2 driver to be weirdo audiophile craz .......
13: Computer Audio Asylum, RE: You can be schooled by Google (0.00)
Posted by John Swenson on 2013-09-23, 13:11:30 (192.19.225.100)
Wow small world, my dad worked at Xerox on the 3Mb ethernet. John S. .......
14: Computer Audio Asylum, RE: Is firewire still better than usb for audio ? (0.00)
Posted by John Swenson on 2013-09-21, 15:56:37 (24.6.202.157)
I on the other hand have had nothing but trouble with FireWire. I have three pro-audio FW interface products and (the least expensive of which was about $1200) and ALL of them have been a nightmare to .......
15: Computer Audio Asylum, RE: OK (0.00)
Posted by John Swenson on 2013-08-30, 13:57:38 (192.19.225.100)
Hi JE, as to measurements, I HAVE done measurements and they are what brought me to a fair amount of what I am doing. The problem is I was not doing them to present a scientific paper, I was doing the .......
16: Computer Audio Asylum, An explanation and proposition (0.00)
Posted by John Swenson on 2013-08-29, 14:07:51 (192.19.225.100)
Somehow it seems I have unintentionaly given the impression that I am against digital audio, that simply is not true. What I have found is that the potential is there to produce extrordinarily good re .......
17: Computer Audio Asylum, RE: How audible are these issues? (0.00)
Posted by John Swenson on 2013-08-26, 13:21:00 (192.19.225.100)
The changes I'm hearing (and others as well) are not gross things like no frequencies below 200Hz or 10% distortion or anything gross like that. It's not even more traditional subtle things like "edge .......
18: Computer Audio Asylum, Very good reason for doing this (0.00)
Posted by John Swenson on 2013-08-23, 11:17:16 (24.6.202.157)
There is a very good reason for upsampling. The DAC chips in most DACs contain oversampling interpolation filters that have been designed to produce good numbers on spec sheets rather than sound good. .......
19: Computer Audio Asylum, RE: Not sound degradation, - that's not what's at play (sic) (0.00)
Posted by John Swenson on 2013-08-19, 15:55:37 (192.19.225.100)
Two reasons as far as I can tell: 1) many USB asynch implementations are not done very well. Even with async USB you STILL need to implement low jitter local clocks and clock networks, have low noise .......
20: Computer Audio Asylum, RE: I was under the impression that the connectors of USB3 are different from USB2 nt (0.00)
Posted by John Swenson on 2013-08-12, 13:45:07 (192.19.225.100)
The "super speed" connection of USB 3.0 is not physically compatible with the high speed, full speed or slow speed connections of USB 2.0. In order to deal with this extra pins have been added to the .......
21: Computer Audio Asylum, Community Squeeze project (0.00)
Posted by John Swenson on 2013-08-06, 17:14:43 (192.19.225.100)
If you guys want some more detail on the Community Squeeze project you can go to communitysqueeze.org, there is a FAQ there that has a lot of detail on the project. There are basically two "Component .......
22: Computer Audio Asylum, RE: Light Harmonic LightSpeed USB cable...BS...or not? (0.00)
Posted by John Swenson on 2013-07-29, 12:51:11 (192.19.225.100)
I don't have this cable and can't talk about it specifically, but at work we use some very high speed cables for very fast data rates (like 20GHz) and these cables are in the $700 to $1000 range, so $ .......
23: Computer Audio Asylum, RE: I'm still not sure I understand (0.00)
Posted by John Swenson on 2013-07-26, 15:49:44 (192.19.225.100)
Hi JE, the difference here is that the test you are refering to is a DIGITAL loopback test. I guess at this point I'll start at the very beginning, I wish I had the skills to do some nice pictures wi .......
24: Computer Audio Asylum, RE: Thanks for the response! (0.00)
Posted by John Swenson on 2013-07-25, 13:57:51 (192.19.225.100)
Hi JE, the issue is not about day to day consistancy, but about "how can different programms that all send the same bits to the DAC sound different?" Is this what you are really after? The insight is .......
25: Computer Audio Asylum, RE: It's not relevant (0.00)
Posted by John Swenson on 2013-07-24, 13:32:09 (192.19.225.100)
HI JE, I'll try and give some real life examples here of how things other than "the bits" could have an affect on the analog output. I've been working on a new USB DAC design recently, so I have a set .......
26: Tube DIY Asylum, RE: Thanks, John... (0.00)
Posted by John Swenson on 2013-07-23, 16:44:27 (192.19.225.100)
The output voltage is always less than .9 times the tgransformer voltage. There is almost always drop across the DCR of the choke. You would have to ask how I do this, I don't have a nice formula, I .......
27: Tube DIY Asylum, RE: choke-input PS for solid state preamplifier? (0.00)
Posted by John Swenson on 2013-07-22, 12:56:52 (192.19.225.100)
I have done extensive experimentation, measurment and listening to this and have come to the conlusion that a choke based supply is almost always the best sounding, although larger, heavier and probab .......
28: Tube DIY Asylum, RE: HV probes... (0.00)
Posted by John Swenson on 2013-07-16, 16:22:16 (192.19.225.100)
Try probemaster.com, they have single ended HV probes and differential HV probes. The differntial probes are neat if you want to do things like look at B+ modulation etc., BUT very expensive. John S. .......
29: Digital Drive, RE: Rayon Fiber Toslink Cable......... (0.00)
Posted by John Swenson on 2013-07-02, 12:02:16 (192.19.225.100)
Hi Thorsten, I recently did a test with a transmitter and receiver from Everlight, the resulting waveforms are MUCH better than those you showed here. The jitter was still terrible, but not nearly as .......
30: Digital Drive, RE: Glass Fiber Toslink (0.00)
Posted by John Swenson on 2013-07-02, 11:42:48 (192.19.225.100)
Actually it has nothing to do with bandwidth, its the size of the fibers. Plastic fibers are much larger than a wavelength of light. Light entering the fiber takes a "zig-zag" path down the fiber, bo .......
31: Computer Audio Asylum, RE: Evidence? (0.00)
Posted by John Swenson on 2013-07-01, 16:59:02 (192.19.225.100)
Unfortunately that last paragraph is just plain wrong. That is how asynchronous mode works not adaptive. Somebody got confused. John S. .......
32: Computer Audio Asylum, RE: GMR (0.00)
Posted by John Swenson on 2013-07-01, 16:53:37 (192.19.225.100)
Hi Fred, I love the GMRs, I've tried a bunch of the isolation technologies around and like them the best. Its the same level of complexity as an optical coupler which has a logic level detector which .......
33: Computer Audio Asylum, RE: Evidence? (0.00)
Posted by John Swenson on 2013-06-30, 23:25:56 (24.6.202.157)
Hi Slider, your last line doesn't make sense, an adaptive sink does NOT send any rate information to the source during isochronous transfer. The adaptive sink needs to adjust it's data rate to match t .......
34: Computer Audio Asylum, RE: How is this consistent (0.00)
Posted by John Swenson on 2013-06-27, 16:22:47 (192.19.225.100)
Yes that is exactly how to do it. What you do is say have 3 zones, a, b ,c. Each zone has completely separate power supply, voltage regulators, ground plane etc. Isolators are used between zones. (I .......
35: Computer Audio Asylum, RE: How is this consistent (0.00)
Posted by John Swenson on 2013-06-27, 12:42:46 (192.19.225.100)
Unfortunately there is at aleast one more clock in there, the PHY clock in the receiver, which is usually a seaprate oscillator which goes through a PLL to boost it to a very high frequncy to deal wit .......
36: Computer Audio Asylum, RE: Packets (0.00)
Posted by John Swenson on 2013-06-27, 12:28:26 (192.19.225.100)
Noisy digital near super sensitive analog is certainly not unique to digital audio, and there are known methods for dealing with it, its just that it seems like many DAC designers are unaware of the s .......
37: Computer Audio Asylum, Packets (0.00)
Posted by John Swenson on 2013-06-26, 12:37:34 (192.19.225.100)
Ah, but the fact that the data comes in packets DOES make a difference. Whenever a packet hits the USB receiver a lot of digital processing takes place to deal with that packet. This causes noise on t .......
38: Computer Audio Asylum, Actual example of mine (0.00)
Posted by John Swenson on 2013-06-25, 14:46:19 (192.19.225.100)
Hi JE, I'd like to share an example of differences in measurement and listening that I went through several years back. First a few words about myself, I am an electronics engineer, proffesionally I d .......
39: Computer Audio Asylum, Very concise statement (0.00)
Posted by John Swenson on 2013-06-24, 16:36:00 (192.19.225.100)
Thanks Fred, that is a very concise statement of the situation. What I see happening a lot is that a designer will get "focused" on one particular aspect of the design that made things sound better in .......
40: Computer Audio Asylum, RE: Julian loved his measurements (0.00)
Posted by John Swenson on 2013-06-21, 16:15:34 (192.19.225.100)
Ha! I built one of these off this article. I etched the board myself, built a chasis by hand, did the whole thing from scratch. It was great fun. It drove a set of speakers I built myself from drivers .......
41: Computer Audio Asylum, RE: So, is anyone using: (0.00)
Posted by John Swenson on 2013-06-17, 13:40:59 (192.19.225.100)
Hi Steve, I did my own XMOS fully isolated DAC, I can bypass the isolation or leave it in. With the isolation different cables make almost no difference, but power supply does make a difference. With .......
42: Computer Audio Asylum, CSOS - Mytek (0.00)
Posted by John Swenson on 2013-06-14, 13:45:28 (192.19.225.100)
Yes, I am designing the hardware platform part of the CS project. There currently is a COSOS image available which does work with the Mytek. CSOS as an image is compiled for the Wanboard, but certain .......
43: Computer Audio Asylum, RE: DSD high frequency noise and conversion to PCM to improve/filter this (0.00)
Posted by John Swenson on 2013-06-12, 13:17:38 (192.19.225.100)
I looked at several DAC chips that handle DSD and looking at the spec sheets I saw a SINC filter response, which seems strange for a DSD DAC. I finally figured out what they were doing, an analog FIR. .......
44: Computer Audio Asylum, RE: You should (0.00)
Posted by John Swenson on 2013-06-07, 13:26:32 (192.19.225.100)
I never said they sound great, just that when hot they sound better! John S. .......
45: Computer Audio Asylum, RE: You should (0.00)
Posted by John Swenson on 2013-06-06, 09:54:56 (192.19.225.100)
That running hot is what makes them sound as good as they do, they rtadically improve in SQ as they warm up (literally). A single one with a power resistor glued to it running DC to heat up the chip a .......
46: Computer Audio Asylum, RE: Here is the real Squeezebox replacement (0.00)
Posted by John Swenson on 2013-05-28, 17:15:11 (192.19.225.100)
The primary advantage is that I am including everything I know on making very good sounding DACs built into this box. Because it is being engineered into the system rather than as an add on box I can .......
47: Computer Audio Asylum, RE: Here is the real Squeezebox replacement (0.00)
Posted by John Swenson on 2013-05-28, 17:09:19 (192.19.225.100)
The original unit (CSP1) (Community Squeeze Player) will definitely be a DIY assembled device. CSP1 will be a beta unit with a small circulation, whoose primary purpose is to shakeout the hardware and .......
48: Computer Audio Asylum, RE: no display. no remote. (0.00)
Posted by John Swenson on 2013-05-28, 17:01:26 (192.19.225.100)
The first versions will be basically "receiver" type devices without builtin displays. They will contain an HDMI jack and several USB jacks. You can add any HDMI display you want to use. A USB port c .......
49: Tube DIY Asylum, RE: Please explain why the top one has 800V over it? (0.00)
Posted by John Swenson on 2013-05-22, 14:09:12 (192.19.225.100)
It's not the resistors, it's the switching power supplies themselves. The input to all of them are at the same potential, but the DC level between that input and the output varies significantly. Even .......
50: Tube DIY Asylum, RE: Maxim GM70 (0.00)
Posted by John Swenson on 2013-05-21, 14:07:42 (192.19.225.100)
Please carefully consider that power supply. It says those switching supplies are from Costco. Given that, you can guarantee they are from China using the cheapest parts known to human kind. That top .......
51: General Asylum, My LED lighting system (0.00)
Posted by John Swenson on 2013-05-14, 14:47:44 (192.19.225.100)
I'm in the process of converting to LED lighting for my whole house. I finally found some 12v fixtures and tapes that have good enouigh light quality for me. I'm quite picky about light quality so thi .......
52: Computer Audio Asylum, Vortexbox (0.00)
Posted by John Swenson on 2013-01-27, 18:59:14 (67.170.250.82)
The easiest linux installation to go for if you want LMS on linux is called Vortexbox (vortexbox.org). It is a linux distribution AND LMS all in one package optimized to be a music server. Just downl .......
53: Computer Audio Asylum, RE: Async vs. Adaptive USB & Computer Tweakiness........ (0.00)
Posted by John Swenson on 2012-12-27, 12:38:19 (192.19.225.100)
I have an interesting take on this, based on a number of devices I have on hand. With a good old 2706 based adaptive DAC, SQ does vary a lot with what's happening on the computer. At it's best it sou .......
54: Computer Audio Asylum, RE: SB Touch & EDO to SPDIF - better than a USB DAC? (0.00)
Posted by John Swenson on 2012-12-20, 14:20:25 (192.19.225.100)
It was with a SBT with EDO. Every DAC connected with USB sounds better connected to the SBT, than to any other computer I have. Some DACs sound better fed S/PDIF than with USB. The SBTs coax jitter i .......
55: Computer Audio Asylum, RE: My experience with turning a Raspberry Pi into a Squeezebox................ (0.00)
Posted by John Swenson on 2012-12-18, 13:55:50 (216.52.185.72)
Aha, squeezelite is a recent program, so it looks like the developer of Squeezeplug is including it in the distro. The developer of Squeezelite hangs out in the Slimdevices forums, you can ask any qu .......
56: Computer Audio Asylum, RE: It's in. (0.00)
Posted by John Swenson on 2012-12-18, 13:41:57 (216.52.185.72)
The specs for the M-DAC show it only going up to 96KHz via USB, which means it does NOT use UAC2.0 so it should be plug and play with Windows 8. Hopefully you have it working by now! John S. ::: TOPI .......
57: Computer Audio Asylum, RE: My experience with turning a Raspberry Pi into a Squeezebox................ (0.00)
Posted by John Swenson on 2012-12-18, 13:06:09 (8.28.19.76)
Since you are using SqueezePlug are you trying to run the server on the Pi or just use it as a player to an external server? There is a new linux squeezebox emulator called Squeezelite which is specif .......
58: Computer Audio Asylum, RE: SB Touch & EDO to SPDIF - better than a USB DAC? (0.00)
Posted by John Swenson on 2012-12-16, 20:18:51 (67.170.250.82)
This is interesting, all the USB DACs I have sound much better connected to the SBT than to other computers (including laptops. The laptops were usually the worst. Now it is true that the USB input o .......
59: Computer Audio Asylum, RE: Listened yesterday, and completed survey. Some comments: (0.00)
Posted by John Swenson on 2012-12-15, 23:48:35 (67.170.250.82)
I just got done listening to these files. I found the difference very easy to tell with the first system I used. Interestingly I had a very different take on what was the easiest music to hear the dif .......
60: Computer Audio Asylum, BGAs (0.00)
Posted by John Swenson on 2012-12-13, 14:29:23 (192.19.218.100)
How in the world do you route a large BGA in two layers? Four is bad enough! Or maybe that is one of the "absolutely necessary" parts. But aren't almost all "chipsets" done in BGAs? I'm just having a .......
61: Computer Audio Asylum, RE: Perhaps (0.00)
Posted by John Swenson on 2012-11-14, 17:20:59 (192.19.218.100)
And what is amazing is how many 75 ohm cables have 50 ohm plugs. A couple years ago I did a study on this, I checked about 30 web sites that sold 75 ohm cables with BNCs (many were aimed at the pro v .......
62: Tube DIY Asylum, RE: A High Altitude Choke (0.00)
Posted by John Swenson on 2012-10-29, 13:03:42 (192.19.218.100)
The thermal issues are always what I have had to deal with. I've designed a bunch of chips for high altitude (and very high altitude (space) use). The decrease in cooling from air flow has been an int .......
63: Computer Audio Asylum, RE: AVB (0.00)
Posted by John Swenson on 2012-10-25, 15:50:26 (192.19.218.100)
AVB seems to have been designed for large multi-device networks. The "common" usage model always talked about in the AVB documentation has a microphone plugged into an ADC sending data to a speaker. I .......
64: Computer Audio Asylum, RE: USB-32 chip---Anyone heard of it? (0.00)
Posted by John Swenson on 2012-09-07, 21:35:04 (67.170.250.82)
Due to the gag order on any info about it from VIA I have no idea. Just another company that makes it impossible to get any info on it unless you are a big customer. As opposed to XMOS who wants every .......
65: Computer Audio Asylum, RE: USB-32 chip---Anyone heard of it? (0.00)
Posted by John Swenson on 2012-09-07, 12:46:28 (192.19.218.100)
I heard from someone that actually has the AudioGD dac that it is the VIA VT1731 chip. The description of this chip seems to match with what AudioGD is saying so I'm pretty sure this is the chip. Joh .......
66: Tube DIY Asylum, RE: thanks for warning me... (0.00)
Posted by John Swenson on 2012-09-06, 16:45:26 (192.19.218.100)
Actually I am a self professed lamp nut. Not on the mechanical properties of the lamp, but on the "light quality". Things look different under different illumination. Just like audio this is a very pe .......
67: General Asylum, RE: How often does 'burn-in' result in a negative change (0.00)
Posted by John Swenson on 2012-09-06, 14:18:45 (192.19.218.100)
Thats interesting, I have a MSII (not the +) and heard almost no difference from burn-in, but I did notice that it sounds radically different when plugged into different computers. Were your pre/post .......
68: Digital Drive, RE: Thanks; trying to clarify my confusion (0.00)
Posted by John Swenson on 2012-08-28, 13:09:55 (192.19.218.100)
I've always had a slightly different definition: Oversampling came to be used in relation to the digital filter used in a DAC chip. Upsampling was an increase in sample rate to the data sent to the DA .......
69: Digital Drive, RE: Oversampling vs. Upsampling: Marketing Speak (0.00)
Posted by John Swenson on 2012-08-28, 12:59:48 (192.19.218.100)
The big advantage with the NOS DAC is that you can use it with software (over/up) sampling which can significantly reduce the aliasing and high frequency drop, BUT bypasses the compromised filter impl .......
70: Computer Audio Asylum, RE: Recovering from a RAID problem (0.00)
Posted by John Swenson on 2012-08-14, 12:00:10 (192.19.218.100)
Yes I did run fschk on the filesystem (ext3) after rebuilding the array, it said everything was fine, but when copying files I still got file errors. At that point since I had backups and was going to .......
71: Computer Audio Asylum, RE: Recovering from a RAID problem (0.00)
Posted by John Swenson on 2012-08-14, 11:48:13 (192.19.218.100)
The primary reason for doing the RAID array was to have a large filesystem made out of smaller disks, multiple smaller disks were way cheaper than one large one. The server runs 24/7. I had done a sh .......
72: Computer Audio Asylum, Recovering from a RAID problem (0.00)
Posted by John Swenson on 2012-08-13, 17:59:03 (192.19.218.100)
Many years ago I built a music server running linux with a bunch of drives in a RAID 5 array (using linux software RAID). The main reason for this was that LARGE disks were still very expensive and my .......
73: General Asylum, RE: Buying on time. (0.00)
Posted by John Swenson on 2012-08-08, 13:47:02 (192.19.218.100)
I've never borrowed for stereo equipment. I HAVE bought a plasma screen and a laptop on "bill me later", the plasma was paid off before any interest was due. The laptop didn't fair so well, but fortun .......
74: Computer Audio Asylum, RE: This excerpt from Mytek is also interesting (0.00)
Posted by John Swenson on 2012-08-07, 15:28:48 (192.19.218.100)
This is interesting, they have to use a PLL on an asynchronous interface? That seems like it's defeating the purpose of an async interface. John S. .......
75: General Asylum, RE: "Bricklayer" (0.00)
Posted by John Swenson on 2012-08-06, 17:03:09 (192.19.218.100)
Those were the Horta. John S. .......
76: Digital Drive, Clock specs (0.00)
Posted by John Swenson on 2012-07-27, 14:18:10 (192.19.218.100)
There are a number of specs for clocks, many of which are unimportant for digital audio. The most import spec is jitter, or phase noise. Getting a phase noise plot is better rather than just a ps numb .......
77: Computer Audio Asylum, RE: DRAM or SRAM? (0.00)
Posted by John Swenson on 2012-07-22, 16:18:49 (67.170.250.82)
Yes it has to be DRAM in order to get enough bytes to hold your 4 GB of music. If you access the DRAM correctly the read accesses will be sufficient for refresh, so there should be no need for separat .......
78: Computer Audio Asylum, RE: Question about DSP and Filtering (0.00)
Posted by John Swenson on 2012-07-20, 15:54:49 (192.19.218.100)
I have been thinking hard about how to reply to this, it's a complex subject. I think I'm going to go with the abreviated version and try and keep it short. That means there is going to be a lot left .......
79: Computer Audio Asylum, RE: Disconnecting remote interface (0.00)
Posted by John Swenson on 2012-07-20, 14:44:46 (192.19.218.100)
I think you are focusing on just one part of the whole concept, you mention that disconnecting the cable doesn't make a difference, but changing thread priorities does make a big difference, but that .......
80: Digital Drive, RE: From a practical standpoint... (0.00)
Posted by John Swenson on 2012-07-16, 17:49:34 (192.19.218.100)
The PCM56P has an opamp on the chip but you don't have to use it, you can connect to the current out if you wish. I have no idea which way the Havanna did it, it can go either way. John S. ::: TOPIC .......
81: Computer Audio Asylum, RE: John, I think it's called an iPod :) (0.00)
Posted by John Swenson on 2012-07-16, 14:54:19 (192.19.218.100)
Hi Gordon, yes the idea was that the connection to the outside world (XMOS or whatever) would be completely powered down during play so there is no way it can affect the SQ. That way you don't actally .......
82: Computer Audio Asylum, RE: Tony's Player (0.00)
Posted by John Swenson on 2012-07-15, 16:55:44 (67.170.250.82)
Hi Klaus, of course a perfect DAC completely immune to any influences from the outside world would be the way to go, but the problem is that nobody knows how to make it. Right now we are in a situatio .......
83: Computer Audio Asylum, RE: Disconnecting remote interface (0.00)
Posted by John Swenson on 2012-07-14, 15:04:01 (67.170.250.82)
The difference here is that all the circuitry that has to do with talking to the ethernet gets completely powered down, when you disconnect the cable from the Touch the circuitry that talks to that ca .......
84: Computer Audio Asylum, RE: Tony's Player (0.00)
Posted by John Swenson on 2012-07-13, 15:37:22 (192.19.218.100)
Hi Steve, if I may paraphrase the discussion: people are going crazy tweaking real time aspects of computers (OS's, player software, amount of memory, processor type, IRQ priorities etc etc etc. Every .......
85: Computer Audio Asylum, Tony's Player (0.00)
Posted by John Swenson on 2012-07-13, 00:15:47 (192.19.218.100)
Below Tony was talking about an interesting concept in a player, I would like to explore this a little bit. Basic concept: simple device that uses ethernet or some other remote mechanism to fill larg .......
86: Computer Audio Asylum, RE: I'm still in shock that NOBODY is getting bit-perfect audio from Linux (0.00)
Posted by John Swenson on 2012-07-11, 18:03:27 (192.19.218.100)
I think you have misinterpreted Tony's statement, he did NOT say that NOBODY gets bit perfect data, he said "then there are the people...." this is a way of saying "SOME people" are not getting bit pe .......
87: Computer Audio Asylum, RE: squeeze box touch usb/sd card (0.00)
Posted by John Swenson on 2012-07-07, 22:22:59 (24.6.177.51)
There are some things you need to know about TinyLMS (the server that runs when you plug an SD card or USB stick). It's called tiny because there are a number of features of the "full" server that are .......
88: Tube DIY Asylum, RE: current through LED for cathode bias (0.00)
Posted by John Swenson on 2012-06-27, 17:34:57 (192.19.218.100)
I have done a bunch of tests and LARGE search through data sheets over the last couple years trying to find the best LEDs to use as voltage references for voltage regulators, the results are probably .......
89: Computer Audio Asylum, RE: Is this achievable? (0.00)
Posted by John Swenson on 2012-06-13, 12:47:18 (192.19.218.100)
There is also the whole Squeezebox system from Logitech. The $250 Squeezebox Touch connects to your system either directly (it has decent analog outs) or through an external DAC. It's designed to talk .......
90: Computer Audio Asylum, RE: Squeezeplay -- SqueezeOS (0.00)
Posted by John Swenson on 2012-06-13, 12:17:35 (192.19.218.100)
This is one of the big debates going on now. My experience has been that lower powered devices sound better, but there are quite a few others that insist that the fastest processors with gazillions of .......
91: Tweakers' Asylum, RE: Manufacturers of PCB prototypes - Recommendations (0.00)
Posted by John Swenson on 2012-06-12, 17:13:17 (192.19.218.100)
I use PCBFabExpress a lot. They have a fairly high setup fee but a very low per inch and multiple board charge thus they are great for larger boards. For small boards I use OSH Park, it's $5 per inch .......
92: Computer Audio Asylum, Squeezeplay -- SqueezeOS (0.00)
Posted by John Swenson on 2012-06-09, 16:39:59 (24.6.177.51)
I have built squeezeplay and squeezeos from the sources and poked around significantly in the sources, so I have a fairly good understanding of what is there. Squeezeplay is a program which contains .......
93: General Asylum, RE: How Long Do Small LED Light Bulbs Last? (0.00)
Posted by John Swenson on 2012-06-08, 14:19:15 (192.19.218.100)
The basic LED lifetime is primarily affected by temperature. The temperature is primarily affected by the current flowing through them. If an LED is rated for 30mA and you run it at 30mA the lifetime .......
94: Digital Drive, RE: Here's what I've decided to do with regards to the USB cable issue... (0.00)
Posted by John Swenson on 2012-06-01, 15:44:19 (192.19.218.100)
Did you know that you can now use the USB connection with the Touch? There is an applet available now which should work fine with the Bifrost. It also enables up to 192 over the S/PDIF as well. Just .......
95: Digital Drive, RE: Slew rate. (0.00)
Posted by John Swenson on 2012-06-01, 15:34:49 (192.19.218.100)
One other incidental affect of the higher drive voltage is increased ground plane noise in the transmitter. This can very easily produce higher jitter. I've actually measured the increase in ground p .......
96: Computer Audio Asylum, RE: Something just clicked... (0.00)
Posted by John Swenson on 2012-05-22, 16:32:01 (192.19.218.100)
The threshold levels in the receiver are the same for AES/EBU and S/PDIF, its the transmitter levels which are different. With the much higher initial levels AES/EBU can withstand vastly greater atten .......
97: Digital Drive, Squeezebox Touch (0.00)
Posted by John Swenson on 2012-05-06, 16:30:13 (192.19.218.100)
With the Enhanced Digital Output applet the Touch can definitely output 192 S/PDIF coax or optical. When using a squeezebox there are a few things you need to take into account, the SB gets the audio .......
98: Computer Audio Asylum, RE: External USB to S/PDIF (0.00)
Posted by John Swenson on 2012-04-20, 17:07:08 (192.19.218.100)
The answer depends partly on what sample rates you want to support (a different protocol is used above 96KHz) and how old your Ubuntu is. Recent versions contain support for UAC2.0 (USB Audio Class) w .......
99: Computer Audio Asylum, RE: Dedicated USB converter or (0.00)
Posted by John Swenson on 2012-04-17, 13:42:34 (192.19.218.100)
An external USB -> S/PDIF converter still needs an S/PDIF receiver in the DAC. A USB receiver in the DAC does not need to go through the S/PDIF conversion and clock extraction process. Although many D .......
100: Computer Audio Asylum, Linear supplies etc. (0.00)
Posted by John Swenson on 2012-04-16, 14:52:50 (192.19.218.100)
Hi Abe, I DID do a lot of checking of all kinds of equipment with scopes, spectrum analyzers etc. In particular how the power supply in one piece of equipment can travel through the mains and affect t .......
101: Computer Audio Asylum, RE: USB cables (0.00)
Posted by John Swenson on 2012-04-12, 22:59:11 (24.6.177.51)
Why doesn't somebody just fix it? Because nobody knows what the problem is. All the obvious primary effects have long been taken care of. Secondary effects have been hypothesized, tested, determined w .......
102: Computer Audio Asylum, A little more detail (0.00)
Posted by John Swenson on 2012-04-11, 21:01:27 (24.6.177.51)
This is an applet which allows you to select which output to use, including USB and an enhanced S/PDIF. In addition it installs a program which supports the 24 bit format used by USB DACs and installs .......
103: Computer Audio Asylum, Old computer as dedicated server (0.00)
Posted by John Swenson on 2012-04-03, 15:45:34 (192.19.218.100)
Yes you should be able to use that old computer as a dedicated server, the memory is a little low, but as long as you don't have other programs starting at boot time you should be OK. You want to make .......
104: Computer Audio Asylum, RE: Optimum set up with SB Touch and uncompressed files through network (0.00)
Posted by John Swenson on 2012-04-02, 15:33:54 (192.19.218.100)
The TT buffer mod only affects the ALSA buffer, not the squeezeplay buffer which stays very large (it can be a couple minutes at 16/44.1) so it has relatively little to do with dropouts etc. You can .......
105: Computer Audio Asylum, RE: you might find this interesting (0.00)
Posted by John Swenson on 2012-03-24, 00:58:08 (24.6.177.51)
The formats would have to be very simple such as flac and wav. Anything else would have to be transcoded in advance. Latency of the transport commands could be quite low, its not a "memory player" in .......
106: Computer Audio Asylum, RE: you might find this interesting (0.00)
Posted by John Swenson on 2012-03-22, 21:55:20 (24.6.177.51)
Here is my thought on an implementation of this. The player part actually consists of two boxes, the disk box and the DAC box. The disk box has the HD, an ethernet interface to talk to the computer an .......
107: General Asylum, RE: Simple, it's the transformers. The raw parts cost of the magnetic metal cores such as Permalloy 45 or (0.00)
Posted by John Swenson on 2012-03-07, 16:58:59 (192.19.218.100)
My 30 watt SE amps have $800 output transformers, the manufacturer hates making these since they are very labor intensive to wind. And thats just using M4 core, no nickel or anything really fancy. Th .......
108: Computer Audio Asylum, RE: OK, here is where I am now... (0.00)
Posted by John Swenson on 2012-02-23, 17:49:40 (192.19.218.100)
What you are seeing is not "normal". I have a little Geode box (600MHz, 256MB memory) running linux that runs an async USB DAC with somewhere around 3% processor usage most of the time. (using MPD) Ad .......
109: Computer Audio Asylum, RE: on last try (0.00)
Posted by John Swenson on 2012-02-14, 17:04:20 (192.19.218.100)
A few thoughts on this. Is the storage medium in the same box as the DAC? If its in a different box how does the data get between the boxes? There are computer peripheral interfaces such as USB or fir .......
110: Tube DIY Asylum, RE: Why is this happening when I test voltages...??? (0.00)
Posted by John Swenson on 2012-02-09, 15:15:42 (192.19.218.100)
Are you putting the leads on the preamp with it turned off, then turning it on, or are you turning it on, letting it stabalize, then putting the leads on? If the latter it might be the probe capacitan .......
111: Computer Audio Asylum, RE: Audio over the USB without USB audio (0.00)
Posted by John Swenson on 2012-02-07, 10:28:44 (192.19.218.100)
This has become fairly popular, a number of companies are doing this such as M2Tech etc. Its not isochronous but if you are running high speed mode and just have the audio device on the controller tha .......
112: Digital Drive, RE: Help with a balanced digital 4 way splitter (0.00)
Posted by John Swenson on 2012-01-31, 17:18:11 (192.19.218.100)
I'm a little leery of the Aphex unit. I personally would do it passively. There is plenty of signal available on a true AES/EBU output to drive 4 inputs without buffering. There are plenty of 1 to 2 .......
113: Computer Audio Asylum, How about one of these (0.00)
Posted by John Swenson on 2012-01-27, 16:16:56 (192.19.218.100)
This is the first commercial tape drive, the Univac uniservo, it used metal foil tapes (they weighed a ton). The tape went through a bunch of pullies connected with fishing line, during operation thos .......
114: Computer Audio Asylum, RE: Squeezebox Smartphone Controller Issue (0.00)
Posted by John Swenson on 2012-01-23, 16:17:37 (192.19.218.100)
There are two android apps in common use, one was written by Logitech and the other is Squeeze Commander. I personally use Squeeze Commander so I don't have experience with the Logitech app. A lot of .......
115: Computer Audio Asylum, RE: PC + Asynchronous USB DAC Question (0.00)
Posted by John Swenson on 2012-01-02, 10:30:24 (24.6.177.51)
Asynchronous USB is not a guarantee that a DAC is immune to all outside influences. What it does is give the possibility of better immunity IF the implementation is done very well. As others have ment .......
116: Computer Audio Asylum, RE: Squeeze Box Touch question (0.00)
Posted by John Swenson on 2012-01-02, 10:00:17 (24.6.177.51)
Take a look at Moose, it is a squeezebox control program for Windows, it should work fine on your computer, and it's free! John S. .......
117: Computer Audio Asylum, RE: Squeeze Box Touch question (0.00)
Posted by John Swenson on 2011-12-29, 12:37:31 (192.19.218.100)
There are many different ways to control a squeezebox system, thats one of its big advantages. There are several programs that run on various OS's (Mac, Windows, Linux) that are dedicated controlers, .......
118: Computer Audio Asylum, RE: Dirty power or broken Sub? (0.00)
Posted by John Swenson on 2011-12-27, 11:17:19 (192.19.218.100)
This sounds like you have high frequency noise from the laptop being injected back into the power mains through the laptop's power supply. Since you didn't hear this when you didn't have the sub in th .......
119: Computer Audio Asylum, RE: Every wire is an antenna. (0.00)
Posted by John Swenson on 2011-12-07, 13:18:13 (192.19.218.100)
Sure there is a lot that can be done, unfortunately its neither easy nor cheap. Another interesting aspect of this is skill sets, its extremely rare to find somebody that is good at everything necessa .......
120: Tube DIY Asylum, RE: I wouldn't do that! (0.00)
Posted by John Swenson on 2011-11-29, 14:26:55 (192.19.218.100)
Its not a current regulator, its a shunt voltage regulator, the CCS feeds a VR tube in parallel with the screen. As the screen takes less current the VR tube takes more etc. I've done this and it wor .......
121: Computer Audio Asylum, RE: Fit-PC Slim vs Alix PC: opinions sought (0.00)
Posted by John Swenson on 2011-11-28, 17:10:44 (192.19.218.100)
The Alix and FitPC slim are pretty similar, the main differences are that the Alix does not have a video subsystem, this can be a significant advantage, a lot less noise running around on the ground p .......
122: Computer Audio Asylum, Completely different approach (0.00)
Posted by John Swenson on 2011-11-12, 08:31:06 (69.181.5.137)
I've gone with a completely different approach. I've had the infamous WRT54GL running openwrt for years, but have switched to using an embedded computer running pfSense for the router and separate swi .......
123: Computer Audio Asylum, RE: Help choosing a Microphone please? (0.00)
Posted by John Swenson on 2011-11-11, 14:35:15 (192.19.218.100)
My favorite Microphones are Earthworks, but they are NOT cheap. Their least expensive mic is probably out of your price range. They don't show up used very often either, the people that have them usua .......
124: Computer Audio Asylum, RE: cPlay and asynchronous USB (0.00)
Posted by John Swenson on 2011-10-21, 17:55:15 (147.145.40.44)
Here is how asynchronous USB works: The hardware on the computer side has a crystal oscillator that it uses to clock out the actual bits to the bus. The bits come in packets which get put together by .......
125: Computer Audio Asylum, RE: hoping for new model (0.00)
Posted by John Swenson on 2011-10-21, 17:21:14 (147.145.40.44)
The hardware in the Touch looks like it WAS designed for 176/192, the big issue is software. The linux drivers are based on Freescale's generic drivers for their chip and they only go up to 96. Logite .......
126: Digital Drive, RE: Jitter busting 75ohm Attenuators (0.00)
Posted by John Swenson on 2011-10-07, 13:10:27 (147.145.40.44)
In general this is not useful. The only case where it makes sense is where the S/PDIF output is not really S/PDIF but single ended AES/EBU which has much higher voltages than true S/PDIF. These higher .......
127: Tube DIY Asylum, RE: The Swenson BDT pre-amp idea has anyone built one - with polarity switching?! (0.00)
Posted by John Swenson on 2011-10-06, 17:05:24 (147.145.40.44)
Since the BDT tube has balanced outputs, you can take single ended output from either plate, just make sure that both plates have the same loading. Or are you trying to do polarity switching using th .......
128: Computer Audio Asylum, RE: Mucho time spent, yet still totally whacked! (0.00)
Posted by John Swenson on 2011-09-26, 17:11:35 (147.145.40.44)
I'd be happy to help try and work this out with you (My big project just finished so I have some time). If you are interested there are a couple things I need from you, First and formost is a detaile .......
129: Computer Audio Asylum, RE: MP3 (0.00)
Posted by John Swenson on 2011-09-24, 22:11:45 (69.181.5.137)
OK, MP3 is NOT one of the problem formats, so that's not the issue. Yep your range extender is probably the problem. I've NEVER had had any luck with those. What DOES work is a wired access point, but .......
130: Computer Audio Asylum, RE: ripped format (0.00)
Posted by John Swenson on 2011-09-23, 15:20:37 (147.145.40.44)
But what is the actual file format, ie the extension in the filename, .mp3, .flac .wav etc. The Touch has about a two minute buffer which takes a really significant dropout to use up. More common is .......
131: General Asylum, RE: Great description! (0.00)
Posted by John Swenson on 2011-09-23, 14:55:37 (147.145.40.44)
My favorite subs are from Rythmik, they are not terribly expensive but they sound amazing. My main speakers are Lowther drivers in enclosures of my own design, the Rythmics work extremely well with th .......
132: Computer Audio Asylum, RE: thumb drive as source into SB Touch? (0.00)
Posted by John Swenson on 2011-09-07, 16:41:46 (147.145.40.44)
There are a couple issues with using storage plugged directly into the Touch, most of which stem from the very small amount of memory on board. The server (TinySBS on the Touch) works by maintaining a .......
133: Tube DIY Asylum, RE: CF final stage (0.00)
Posted by John Swenson on 2011-08-29, 18:35:16 (147.145.40.44)
I've done something similar as well and came to the conclusion the culprit was the non constant voltage on the screen changing the characteristics of the tube and also changing screen current. The res .......
134: Tube DIY Asylum, RE: A 5 watt 211 SE amp. Worth the trouble? warning long and slightly err long! (0.00)
Posted by John Swenson on 2011-08-29, 18:20:13 (147.145.40.44)
I once did a low voltage 211 that always runs in A2. The grid never goes negative. The driver is the tricky part with this. I used a high transconductance pentode in CF mode with a CCS to load it to c .......
135: Tube DIY Asylum, RE: 1100V supply issues (0.00)
Posted by John Swenson on 2011-08-29, 17:27:32 (147.145.40.44)
What I've done is put chokes in series. My latest supply has 4 cheap chokes in series, this distributes the Vac across the 4 so they don't saturate. This is also 4X the inductance of each one and 4X t .......
136: Tweakers' Asylum, Lack rack and sandbox (0.00)
Posted by John Swenson on 2011-08-23, 18:27:03 (8.19.13.22)
I went from a "flexi" rack with a sandbox under the turntable (Well Tempered RP) to a lack rack, the turntable on the sandbox sounded terrible, it sounded great with spikes between the 'table and the .......
137: Computer Audio Asylum, RE: Usb isolator/extender by (0.00)
Posted by John Swenson on 2011-08-22, 15:39:07 (8.19.13.22)
You still have to pay the $900, the optical cable still plugs into the H1 PCIe adapter so you still have to spend $380 something for both parts. So there HAS to be some sort of driver that talks to t .......
138: Computer Audio Asylum, Try this (0.00)
Posted by John Swenson on 2011-08-08, 16:52:29 (72.52.96.11)
Perusing the USB spec I see that a device on a suspended port is only allowed up to 2.5mA. Since nothing is connected to the D- D+ pins, the host controller will never take that port out of suspend. T .......
139: Digital Drive, RE: SPDIF - TOSLINK question (0.00)
Posted by John Swenson on 2011-08-05, 14:35:01 (72.52.96.11)
An S/PDIF data stream has two transport mechanisms, electrical and optical. The electrical usually uses RCA connetctors (but sometimes BNC) and the optical uses TOSLINK. The data is exactly the same i .......
140: Computer Audio Asylum, RE: Will a juli@ fit in a nf96fl-510-lf? (0.00)
Posted by John Swenson on 2011-08-05, 14:09:12 (72.52.96.11)
I think its more going to be an issue of case rather than motherboard. I see nothing about the board that would preclude it from accepting a Juli@. But it IS a full height board and very few miniITX c .......
141: Computer Audio Asylum, RE: Wouldn't the ideal computer audio system be a separate device like a Squeezebox touch?........ (0.00)
Posted by John Swenson on 2011-07-26, 16:41:06 (192.19.218.100)
The traditional problem is that all the implementations of this use some sort of processor that is processing the network stream, extracting the data and moving it around through different systems and .......
142: General Asylum, Works in other forums, but not here (0.00)
Posted by John Swenson on 2011-07-22, 17:35:07 (192.19.218.100)
Other forums seem to keep tyrack of what has been read now, but General does not. John S. .......
143: General Asylum, RE: Good question (0.00)
Posted by John Swenson on 2011-07-20, 15:41:40 (147.145.40.44)
Audioengine was showing their active speakers for $200. But my favorite less expensive system was at Nappa Acoustic, they had a mini system with tube/SS integrated amp and speakers for $600. IMHO this .......
144: Tweakers' Asylum, RE: Pattern file (0.00)
Posted by John Swenson on 2011-07-14, 12:33:57 (147.145.40.44)
Thanks! Thats perfect. Now to build one. Thanks again, John S. .......
145: Computer Audio Asylum, RE: Good answers. Here's another hard question. (0.00)
Posted by John Swenson on 2011-07-14, 12:28:05 (147.145.40.44)
On the "threshold of audibility" issue I think its enlightning to look at another field. Photographic film takes a certain brightness to cause any change at all in the film when developed, BUT a much .......
146: Tweakers' Asylum, Pattern file (0.00)
Posted by John Swenson on 2011-07-13, 14:59:44 (147.145.40.44)
Hi Rocky, this is very interesting, do you have a file or formula for the pattern that you can share? Thanks, John S. .......
147: Cable Asylum, RE: Audioquest F-88 speaker flat cable (0.00)
Posted by John Swenson on 2011-07-11, 17:44:26 (147.145.40.44)
F-88 is one of my most favorite cables of all time. To me it has a very neutral sound, good solid bass and a nice smooth extended high end and lets the midrange textures through without accentuating t .......
148: Digital Drive, RE: Older Audio Note DAC 3 Opinions Needed (0.00)
Posted by John Swenson on 2011-07-11, 17:25:23 (147.145.40.44)
I had one for many years. I sold it when the ones I was making myself sounded better. Its definately not as good as the current ones but it still sounds quite good. It sounds better than a lot of DACs .......
149: Tube DIY Asylum, RE: How to bridge from kit building to individual DIY (0.00)
Posted by John Swenson on 2011-07-11, 16:57:01 (147.145.40.44)
I did things in a somewhat different way than many here. I bought a pair of cheap hammond output transformers with a a bunch of taps, a power transformer with a bunch of taps. I put together a power s .......
150: Tweakers' Asylum, RE: Replacement of Toroid transformer with an equivalent R-Core type (0.00)
Posted by John Swenson on 2011-07-06, 01:01:51 (69.181.5.137)
There is no electrical reason why the base should be connected or not connected directly to the chassis. A rubber sheet can offer some mechanical damping which might improve sonics, its best to try it .......
151: Tweakers' Asylum, RE: Replacement of Toroid transformer with an equivalent R-Core type (0.00)
Posted by John Swenson on 2011-07-05, 14:31:33 (69.181.5.137)
Since the original has two windings, you have a choice in the R-core, get one with two windings like the original OR figure out how the original is hooked up and get an R-core that matches. For exampl .......
152: Tweakers' Asylum, RE: LOL like enough folks trash the idea, and you want more? (0.00)
Posted by John Swenson on 2011-06-30, 23:59:02 (69.181.5.137)
Naw, the vasoline damps mechanical resonances thereby inhibiting standing waves excited by low frequency seismic noise coming through the floor. Of course you are probably better off with the cable li .......
153: General Asylum, RE: Hmmm. More compression please. (0.00)
Posted by John Swenson on 2011-06-30, 23:43:15 (69.181.5.137)
I do a LOT of live sound and I prefer NOT to use compression. I agree with the others that it makes the wonderful live sound, sound like a CD. Unfortunately sometimes that's what the artists want. A .......
154: Computer Audio Asylum, RE: question is: (0.00)
Posted by John Swenson on 2011-06-16, 13:06:15 (147.145.40.44)
I've actually yet to find a FW interface where the first order effects are very low. I'm sure they exist somewhere, but I haven't found one yet. The Metric Halo units are probably the best candidates .......
155: Computer Audio Asylum, Comparisons with other interfaces (0.00)
Posted by John Swenson on 2011-06-15, 15:04:24 (147.145.40.44)
After reading what has been said on this thread about USB and other interfaces I'd like to make some comparisons based on the same issues I brought up with USB. First off some definitions, note these .......
156: Computer Audio Asylum, RE: How can USB performance impact audio quality? (0.00)
Posted by John Swenson on 2011-06-12, 20:02:54 (69.181.5.137)
This has also bothered me for some time, especially when you have an asynchronous interface which is supposed to prevent such things from happening. After a LOT of investigation and experimentation I .......
157: Computer Audio Asylum, RE: O.T. Which sounds better? Please vote (0.00)
Posted by John Swenson on 2011-06-10, 15:49:34 (147.145.40.44)
All the features are available with any regular phone. They do sell their own wireless phone, but its no different than any other decent wireless phone, my panasonic does exactly the same things. The .......
158: Computer Audio Asylum, RE: O.T. Which sounds better? Please vote (0.00)
Posted by John Swenson on 2011-06-10, 14:42:16 (147.145.40.44)
I just switched to Ooma from comcast, we had nothing but problems with the comcast system. It frequently stopped sending data in one direction, I could hear the person on the other end, but they could .......
159: Digital Drive, Netjack hardware (0.00)
Posted by John Swenson on 2011-06-06, 17:10:38 (147.145.40.44)
Yep, netjack2 is what I have used. I've been trying to find hardware I liked to implement a hardware version. I finally did (I specifically did NOT want to just put an IP stack on a genral purpose pro .......
160: Computer Audio Asylum, RE: CMP X Bryston X Auraliti L1000 (0.00)
Posted by John Swenson on 2011-05-28, 11:59:03 (69.181.5.137)
Recent ALSA releases fully support the Juli@. So most recent linux distributions will work with the card out of the box. I'm actually building a little box right now with one of the early Via mini-ITX .......
161: Digital Drive, RE: Thanks. Didn't they sell a unit with a NOS Dac chip? nt (0.00)
Posted by John Swenson on 2011-05-28, 11:47:25 (69.181.5.137)
According to their site all their products are NOS. The 801 uses the 1704, the 602 and 601 use 1543. I'd never heard of these before, they sound very intriguing. I'd love to hear one. John S. ::: TOP .......
162: Computer Audio Asylum, RE: Pinging Charles Hansen (0.00)
Posted by John Swenson on 2011-05-25, 16:11:57 (147.145.40.44)
Ahh, thats EMP, and tubes less susceptibilities to it are more concerned with the fact that they can withstand short high voltage spikes that would fry solid state parts. Susceptibilites to RFI depen .......
163: Computer Audio Asylum, RE: Pro or con: Are ferrite beads at the end of usb and/or spdif cables really necessary? (0.00)
Posted by John Swenson on 2011-05-25, 15:39:08 (147.145.40.44)
Those ferrite clamp thingies are there to decrease the EMI radiated from the cable, NOT to improve the transmission of the signal through the cable. Its theoretically possible for them to change the i .......
164: Computer Audio Asylum, RE: Burn in doesn't need to be measured... (0.00)
Posted by John Swenson on 2011-05-23, 19:00:35 (69.181.5.137)
Yes I experience burn in all the time, and it bugs the heck out of me! I design and build my own equipment, this burn in stuff means I can't make a change and listen to it right away to evaluate its e .......
165: Computer Audio Asylum, RE: Please listen to it and let us know......................... (0.00)
Posted by John Swenson on 2011-05-17, 16:28:59 (147.145.40.44)
That sounds like it has a current limit function. You want to set that so its greater than the device will ever use (say 2A if not powering a USB drive). Adjust the output to 5V (use a DMM to measure .......
166: Computer Audio Asylum, RE: Please listen to it and let us know......................... (0.00)
Posted by John Swenson on 2011-05-17, 16:22:46 (147.145.40.44)
A Touch which is not powering a USB drive uses between 1 to 1.5A. The 3A is to make sure it can also power USB drives. John S. .......
167: Tweakers' Asylum, LEDs (0.00)
Posted by John Swenson on 2011-05-13, 17:15:59 (147.145.40.44)
I have also just switched to LEDs in my listening room. I wanted to have dimming capability but normal dimmers are horrible in a listening room. What I found was long strips of LEDs with three circuit .......
168: Tube DIY Asylum, RE: Just curious after seeing some nice old variable Mu pentodes. Any good for use as volume control? (0.00)
Posted by John Swenson on 2011-04-21, 17:12:01 (147.145.40.44)
The BDTs are extremely linear on the deflectors. Unfortunately the the "effective" Mu is pretty low, I had to cascode them to get decent gain out of them. For preamp use where you don't need much gain .......
169: Tube DIY Asylum, Hammond voltage ratings (0.00)
Posted by John Swenson on 2011-04-06, 16:00:34 (147.145.40.44)
I asked a Hammond rep about this a while back and found out that the voltage ratings have NOTHING to do with safe voltages, what they are is a way to specify where the core is going to saturate. If yo .......
170: Computer Audio Asylum, RE: Added a DAC to the SB Touch (0.00)
Posted by John Swenson on 2011-04-05, 21:38:30 (24.23.222.123)
The volume value on the Touch is rather complex, there is a slider in lua which sends data to other lua routines which convert to different ranges, on the low side there is a 0-100, 0-99 and 1-100, th .......
171: Computer Audio Asylum, RE: SB Touch question (0.00)
Posted by John Swenson on 2011-04-05, 18:12:33 (147.145.40.44)
This is probably a firmware/server mismatch. Logitech is in the process of rolling out 7.5.4 server and firmware. Mysqueezebox.com has upgraded already, so if you connect to it for any reason it will .......
172: Tweakers' Asylum, RE: 75 ohm S/PDIF digital output, RCA or BNC connector? (0.00)
Posted by John Swenson on 2011-03-15, 13:38:43 (147.145.40.44)
IF the source has a BNC and the DAC has an RCA then you should use a cable with BNC on one end and RCA on the other. If both source and DAC have RCAs then use an RCA to RCA cable. BNC connectors come .......
173: Tube DIY Asylum, RE: CCS feed, shunt regulators using VR tubes (0.00)
Posted by John Swenson on 2011-03-11, 17:41:04 (147.145.40.44)
I've been using Gary Pimm CCSes and VR tubes for pentode screen supplies for quite sometime. The big 813 amp takes a fairly high voltage on the screen so it takes 4 VR tubes in series to get the right .......
174: Computer Audio Asylum, RE: How to connect an NAS to squeezebox touch (0.00)
Posted by John Swenson on 2011-03-11, 17:20:28 (147.145.40.44)
There are a couple options here. You can get a NAS, put the files on the NAS and put the server on the NAS. This way there is no need for another computer to be on. BUT you have to have a NAS with a p .......
175: Computer Audio Asylum, RE: Upsampling? (0.00)
Posted by John Swenson on 2011-03-11, 16:24:40 (147.145.40.44)
When using the Touch iTunes has nothing to do with it. The Squeezebox Server (SBS) runs on the Mac and reads the music files directly. SBS streams the music data over the network to the Touch, iTunes, .......
176: Computer Audio Asylum, RE: Good suggestion. Not available in Thailand yet. nt (0.00)
Posted by John Swenson on 2011-03-05, 22:25:28 (24.23.222.123)
How is shipping to Thailand? Amazon says thy ship there, but I don't know about customs etc. John S. .......
177: Computer Audio Asylum, RE: "Win7 Pro X64 -) JR Media Center 16 (beta) -) ASIOv2 -) Cardas Clear USB -) QB-9 (latest version..." (0.00)
Posted by John Swenson on 2011-03-05, 15:46:35 (24.23.222.123)
Hi Kurt, have you thought of a Squeezebox Touch? You might have a better chance of getting one of those in Thailand since its a "consumer" item rather than an "audiophile" item. You can use one conne .......
178: Computer Audio Asylum, RE: Internet radio, one room only - SB3 or Touch (0.00)
Posted by John Swenson on 2011-03-05, 13:03:34 (24.23.222.123)
The Touch sounds better, which may or may not be important to you. The SB3 has a wider screen, that means it can use bigger fonts which makes it easier to see from across the room. The Touch has a col .......
179: Computer Audio Asylum, RE: Question (0.00)
Posted by John Swenson on 2011-02-18, 15:02:07 (147.145.40.44)
This sounds like the Touch was not connecting to the DHCP server so it never got an IP address. At this point I would try going to the linux pc and try pinging the Touch. Also try loging into the Tou .......
180: General Asylum, RE: suspended floor with crawl space is no good (0.00)
Posted by John Swenson on 2011-02-17, 15:57:41 (147.145.40.44)
I got around the problem by suspending the speakers from the ceiling. It works great, just don't run into them! Its easy to miss the black strings and whack them with something when walking through th .......
181: General Asylum, RE: Yea, I hear ya. (0.00)
Posted by John Swenson on 2011-02-15, 13:50:14 (147.145.40.44)
I'm also getting some stuff from superbrightleds.com. They have some very nice LED strips with warm white specs. Since they run off 12V you can choose your 12V supply for low noise performance. For m .......
182: Computer Audio Asylum, RE: PS - can you... (0.00)
Posted by John Swenson on 2011-02-14, 16:10:04 (147.145.40.44)
The most likely issue is UDP. The server and the player use UDP to find each other. The player will broadcast a message using UDP that essentially says "are there any servers out there", if UDP is blo .......
183: Computer Audio Asylum, RE: Logitech Squeezebox Touch (0.00)
Posted by John Swenson on 2011-02-11, 23:32:47 (67.169.141.86)
From your posts its not quite obvious what you have done. The Touch as you get it out of the box has a very old firmware version, it needs to be upgraded with new firmware before its much good at all. .......
184: Computer Audio Asylum, RE: Logitech Squeezebox Touch (0.00)
Posted by John Swenson on 2011-02-10, 11:00:35 (147.145.40.44)
The player software in the Touch talks to a server (SBS). If you plug in a USB or SD card a program called TinySBS runs on the Touch, its a stripped down version of the regular server. The basic funct .......
185: Tube DIY Asylum, RE: or finding a parafeed capacitor you trust at 700V.... (0.00)
Posted by John Swenson on 2011-01-13, 10:01:43 (67.169.141.86)
For my 813 amp which runs with a B+ of 700V I'm using a 660VAC motor run cap for the parafeed cap. So far its worked very well. John S. .......
186: Computer Audio Asylum, RE: Squeezebox touch (nt) (0.00)
Posted by John Swenson on 2010-12-03, 18:44:00 (147.145.40.44)
The Touch works best with an external server, but it does not have to be a big expensive power hungry computer. There are devices such as the VortexBox which are designed to sit in another room and ju .......
187: Computer Audio Asylum, RE: But it's not a 'memory' player or is it?? (0.00)
Posted by John Swenson on 2010-12-03, 18:38:18 (147.145.40.44)
The Touch is primarily a network player designed to get data from SqueezeBoxServer (SBS) which can run on all kinds of computers. There is a stripped down version called TinySBS which will run on the .......
188: Computer Audio Asylum, Squeeze Commander (0.00)
Posted by John Swenson on 2010-12-03, 18:30:27 (147.145.40.44)
There is an android app called Squeeze Commander that works similar to iPeng. Its by a different programmer so its obviously not the same thing, but it offers similar functionality. John S. ::: TOPIC: .......
189: Computer Audio Asylum, Yes it is (0.00)
Posted by John Swenson on 2010-12-01, 12:55:16 (147.145.40.44)
If you are using gstreamer its easy, just change the output plugin to alsasink instead of pulsesink and any gstreamer app will go direct to alsa. The easiest way to do this is with the program gstream .......
190: Computer Audio Asylum, RE: It's even worse than that (0.00)
Posted by John Swenson on 2010-11-30, 20:17:41 (147.145.40.44)
Actually it works very well if you just turn off all the mixer stuff and have the player go directly to the ALSA device. If your players insist on just going to the default device its really simple to .......
191: Computer Audio Asylum, RE: Update: PulseAudio currently does not support dynamically changing sample rate (0.00)
Posted by John Swenson on 2010-11-30, 20:11:42 (147.145.40.44)
There is another solution, don't use pulseaudio for your high quality music. Configure your player to output directly to your high quality output device (whatever it may be) and if you have to have th .......
192: Computer Audio Asylum, RE: Linear Supply (0.00)
Posted by John Swenson on 2010-11-30, 20:04:30 (147.145.40.44)
Here is the schematic. The Hammond choke is the critical part of the design. Its designed to operate at line frequency (100 or 120Hz). Many people try and substitute the small "common mode" chokes whi .......
193: Computer Audio Asylum, Touch optimizations (0.00)
Posted by John Swenson on 2010-11-28, 18:00:12 (147.145.40.44)
I'm going to come at this from a very different approach than others and give you some options for optimizing the Touch. You can get quite a bit better sonics than what you are getting right now. Fir .......
194: MagneQuest/Peerless Forum, RE: Not a good idea! (0.00)
Posted by John Swenson on 2010-11-23, 11:38:02 (147.145.40.44)
I've done this quite a few times. What I wound up doing is using a MC step up transformer with a low primary DCR (1-2 ohms) with a 1:10 ratio and putting 500-1K ohm resistor on the secondary. My exper .......
195: Computer Audio Asylum, RE: Problems playing hires in Linux (0.00)
Posted by John Swenson on 2010-11-21, 15:20:53 (147.145.40.44)
Squeezeslave only runs at 44.1. I had a very old version that I hacked up for running at higher frequency. (like 5 years ago) I don't think I even have that any more, the machine it was on went bonker .......
196: Computer Audio Asylum, RE: Vortexbox: what (Linux) soundcard does up to 24/192 bit transparent? (0.00)
Posted by John Swenson on 2010-11-15, 14:48:48 (147.145.40.44)
The Juli@ has full support in later linux versions. The 12-12M also has a good linux driver which I'm pretty sure supports 192. John S. .......
197: Tube DIY Asylum, Bad rectifier (0.00)
Posted by John Swenson on 2010-11-11, 12:34:04 (147.145.40.44)
The only time I've had a cap explode like that it was caused by a bad rectifier. This can dump large AC current through the cap which can cause it to explode. The problem is that you can have a parti .......
198: Computer Audio Asylum, Power supplies and Touch (0.00)
Posted by John Swenson on 2010-11-07, 18:03:49 (147.145.40.44)
I've done a lot of measuring and listening to different supplies with the Touch and other SB devices. My major conclusion is that they have relatively little to do with the quality of power reaching t .......
199: Tube DIY Asylum, RE: Green PT is gone, have some Westinghouses left ...Free (nt) (0.00)
Posted by John Swenson on 2010-11-06, 00:03:31 (67.169.141.86)
Hi Jeff, it came today, wow that is SOME transformer! That looks like one very high quality unit, I wonder what it cost originally. Thanks very much, its going to go to good use. John S. .......
200: Computer Audio Asylum, RE: Building a Music Servlet (0.00)
Posted by John Swenson on 2010-10-29, 18:41:10 (147.145.40.44)
I have both a squeezebox Touch and have built (c). I use a fitPC slim running stripped down version of puppy linux. Its designed so it can run off a USB stick without a HD. It allocates part of memory .......
201: Tube DIY Asylum, RE: Green PT is gone, have some Westinghouses left ...Free (nt) (0.00)
Posted by John Swenson on 2010-10-29, 17:07:17 (147.145.40.44)
Hi Jeff, I would love one of the Westinghouse ones if they are still available. My email is broken right now, it will be later tonight before I can get an email to you. Thanks, John S. .......
202: Computer Audio Asylum, RE: Many Questions about getting as hi-end a PC Audio system as possible with what I currently own:)! (0.00)
Posted by John Swenson on 2010-10-29, 16:16:37 (147.145.40.44)
I'm a big fan of the Squeezebox system, particularly the Squeezebox Touch. Its just 2 channel audio, it doesn't do video and it doesn't do multichannel audio (well you can play something like a 5.1 DT .......
203: Computer Audio Asylum, RE: Thanks (0.00)
Posted by John Swenson on 2010-10-28, 17:36:20 (147.145.40.44)
I'm doing something very similar to Ted, I'm using the smallest FPGA that Altera makes and can easily do a 1K FIR with 58 bits internal precision. I think the issue was using FPGAs with builtin DSP "c .......
204: Computer Audio Asylum, RE: SB Touch: Two new mods on the blog (0.00)
Posted by John Swenson on 2010-10-21, 09:51:19 (147.145.40.44)
I haven't had time to test out the screen off part, it looks like its setting a GPIO bit, do you know what this line is connected to? I've been trying to work with the driver to actually shut down th .......
205: Digital Drive, RE: Product Quality as a function of designer belief systems (0.00)
Posted by John Swenson on 2010-10-19, 15:41:25 (147.145.40.44)
What I see happening on regular basis is that a designer finds that improving X parameter improves the sound, so he goes off and tweaks that parameter no matter what the cost, spending huge amounts of .......
206: Computer Audio Asylum, RE: Is there a replacement for the Fit-PC Slim (0.00)
Posted by John Swenson on 2010-10-18, 17:31:32 (147.145.40.44)
The fit-pc1 is still listed on the compulab web page. Its physically larger than the slim and only has 2 USB ports, but uses the same exact processor module. It should be exactly the same from a perfo .......
207: Computer Audio Asylum, Here is what is happening (0.00)
Posted by John Swenson on 2010-10-14, 18:11:50 (147.145.40.44)
Fresh out of the Box the firmware in the Touch will not let you do anything until it has downloaded the most recent firmware. It does this by connecting to mysqueezebox.com. There is no way around thi .......
208: Computer Audio Asylum, RE: Thanks for the Replies (0.00)
Posted by John Swenson on 2010-10-11, 18:06:13 (147.145.40.44)
I have done all this, you are better off just going the squeezebox route. The system is so flexible and extensible its hard to imagine going back to anything else. The SB Touch driving a really good D .......
209: Tube DIY Asylum, RE: Nothing wrong with thinking about electronic designs, but.... (0.00)
Posted by John Swenson on 2010-10-10, 16:15:44 (67.169.141.86)
The small cap after the shunt is just for the gas tubes, other means of shunt have no problem with it. For the gas tubes its a problem because the strike voltage is considerably higher than the sustai .......
210: Computer Audio Asylum, RE: Very bad idea, if I understand correctly (0.00)
Posted by John Swenson on 2010-10-09, 17:13:11 (147.145.40.44)
My main server IS RAID 5. I put this together several years ago when 1TB disks were just starting to come out and were very expensive. My local computer store had a screaming good sale on 256K drives .......
211: Tube DIY Asylum, RE: I've known a defectve capactor to cause a problem like this (0.00)
Posted by John Swenson on 2010-10-05, 00:35:43 (67.169.141.86)
The first thing that comes to mind is a bad cap or diode, but you say you've replaced them all, so thats probably not it. Next I would use a scope to poke around in the circuit and see what the oscill .......
212: Tube DIY Asylum, RE: Explanation (0.00)
Posted by John Swenson on 2010-10-01, 12:03:46 (147.145.40.44)
Hi Michael, I have a "flywheel" design for my big 813 amp which works very well except for one thing, the input current pulses are still pretty high and I want to reduce that. I also came across the .......
213: Tube DIY Asylum, RE: I keep on learning new things (0.00)
Posted by John Swenson on 2010-10-01, 11:47:02 (147.145.40.44)
I have one of these for my 813 amp which delivers 700VDC out the end and am using 1200V Cree Schottky rectifiers with no problem. The only time I had a problem was when I accidentally shorted the sup .......
214: Tube DIY Asylum, RE: Michael, (0.00)
Posted by John Swenson on 2010-09-24, 17:54:30 (147.145.40.44)
I've actually been delving into this extensively in the last month. I've come to the conclusion that the big problem is non-constant transconductance. Any source follower is going to have second harmo .......
215: General Asylum, RE: Audiophiles on SF Peninsula; need a rig (0.00)
Posted by John Swenson on 2010-09-24, 09:55:36 (147.145.40.44)
I have an extra turntable, CDP and cassette deck, but no receiver or power amp or speakers. I'm across the bay in Fremont. John S. .......
216: Computer Audio Asylum, RE: For bits are bits ers - Read This. Scrith too (0.00)
Posted by John Swenson on 2010-09-18, 21:53:42 (147.145.40.44)
Many years ago my dad was designing some sensor circuits for a factory, they needed to get data out of the sensor and back to the control room. The factory floor was so bad electrically they simply co .......
217: Digital Drive, RE: Partially disagree (0.00)
Posted by John Swenson on 2010-09-11, 17:00:18 (147.145.40.44)
Hi Charles, I was deliberately not saying what sounds better, just that they are not the same thing. There actually are several apodizing filters that use linear phase, most of these are built into D .......
218: Tweakers' Asylum, RE: Graham Law of Diffusion (0.00)
Posted by John Swenson on 2010-09-09, 17:28:55 (147.145.40.44)
Years ago I was building a helium ion accelerator. I had a vacuum chamber for the accelerating, I needed a slow and steady source of helium atoms. I wound up with an aluminum disk with some holes in i .......
219: Digital Drive, Some definitions (0.00)
Posted by John Swenson on 2010-09-09, 13:14:36 (147.145.40.44)
There is a lot of confusion about this subject. I'll try and unravel some of this, hopefully without getting too technical. There are two independent things that have become intertwined in most people .......
220: Tube DIY Asylum, Recovery time (0.00)
Posted by John Swenson on 2010-09-04, 17:16:11 (67.169.141.86)
What I see happening and why I design supplies with fast recovery relates to transients and how thay are handled. This all started when I was looking at the waveforms from CDs on the computer and putt .......
221: Computer Audio Asylum, RE: Don't use long USB cables (0.00)
Posted by John Swenson on 2010-09-02, 16:59:32 (147.145.40.44)
I think Gordon was referring to the optical USB cables. They work very well for long distance USB (especially if you put a really good PS on the far end). They are not cheap though. Given the other re .......
222: Computer Audio Asylum, RE: Solid State USB DAC or Tube USB DAC for a Tube Based System? (0.00)
Posted by John Swenson on 2010-09-01, 14:39:31 (147.145.40.44)
I have built both tube and SS DACs with all kinds of different topologies. The upshot is that I'm of the opinion that there is no such thing as a "tube sound" or "SS sound". There are MANY different w .......
223: General Asylum, RE: good idea (0.00)
Posted by John Swenson on 2010-09-01, 14:20:02 (147.145.40.44)
I actually built such a thing in high school. It started out as a laser interferometer for measuring gravitational effects. I was using mirrors mounted on speaker cones to precisely set the pointing o .......
224: Computer Audio Asylum, RE: Async USB via SB Touch? (0.00)
Posted by John Swenson on 2010-08-27, 15:36:26 (147.145.40.44)
I could send it to you, but there are problems. The Touch uses some proprietary binary drivers which are not made available on the web. Logitech merges these into the kernel when they release firmware .......
225: Digital Drive, RE: Peachtree Sabre Dac vs Wyred (0.00)
Posted by John Swenson on 2010-08-26, 15:41:52 (147.145.40.44)
I have a Peachtree Nova but I have not heard the W4S DAC. One thing to note is that the review specifically states the fixed outputs on the Peachtree were used. Its been my experience (and others as w .......
226: Computer Audio Asylum, RE: Async USB via SB Touch? (0.00)
Posted by John Swenson on 2010-08-22, 17:41:06 (67.169.141.86)
Some Async USB interfaces require a custom driver, others will work with the generic drivers that come with OS's. Up until very recently the dividing line was if it played 192. The original USB audio .......
227: Digital Drive, RE: NOS Dac without any digital or analogue filters (0.00)
Posted by John Swenson on 2010-08-11, 15:47:27 (147.145.40.44)
Yes a transformer can be used as part of the ultrasonic filter process. A few things about passive/active output stages. Most of the R2R DAC chips are current out with fairly low currents. These are .......
228: Tweakers' Asylum, RE: Does anyone make midget circuit breakers? nt (0.00)
Posted by John Swenson on 2010-08-05, 16:54:10 (147.145.40.44)
How about these. I've never tried them, but they look like they should do. John S. .......
229: Computer Audio Asylum, RE: Apple or... ? (0.00)
Posted by John Swenson on 2010-08-05, 12:51:36 (147.145.40.44)
If you are willing to dedicate the computer to be a server putting VortexBox on it is a great way to go. Its has its on OS (linux) so you don't need to worry about any Windows stuff anymore. It comes .......
230: Tweakers' Asylum, "flame proof" resistors (0.00)
Posted by John Swenson on 2010-08-04, 16:21:59 (147.145.40.44)
A couple years ago I was working on a friends amp that wasn't quite working right. I was bending over the circuit with a scope probe and was about to touch a wire (hadn't actually touched it yet!) whe .......
231: Tweakers' Asylum, RE: (strong)REVIEW: Audio Prism Ground Control Cable(/strong) (0.00)
Posted by John Swenson on 2010-08-04, 15:19:56 (147.145.40.44)
This has been talked about a lot over at diyaudio.com. It IS just a loop of many strands of insulated wire, with some insulating material wrapped around the bundle at various locations. The amount and .......
232: Tube DIY Asylum, RE: New project: Tube Microphone Preamp (0.00)
Posted by John Swenson on 2010-08-03, 13:39:44 (147.145.40.44)
I did a mic preamp a couple years back which was a differential pair of D3as. The input was DC coupled, it got interesting with phantom power. Because the CCS on the tail was run from a negative suppl .......
233: Tube DIY Asylum, RE: Parallel SET?? (0.00)
Posted by John Swenson on 2010-07-30, 18:52:49 (147.145.40.44)
I use parafeed with mine. Magnaquest has some high current plate chokes and parafeed OPTs that work well with 813s. John S. .......
234: General Asylum, RE: Marigo Isolation Feet (0.00)
Posted by John Swenson on 2010-07-30, 18:05:56 (147.145.40.44)
They are very good, music seems much "cleaner" with these. They don't seem to change the overall balance, music just seems to have much less "grunge" that you didn't realize was there before. They ha .......
235: Computer Audio Asylum, These are my favorite (0.00)
Posted by John Swenson on 2010-07-21, 14:15:55 (147.145.40.44)
The mercury delay line memory was my favorite. My dad actually worked with these every day. I saw one at the Smithsonian and knew immediately what it was from my dad's description. At one point the me .......
236: Computer Audio Asylum, RE: How is the DAC in the SB Touch? (0.00)
Posted by John Swenson on 2010-07-15, 23:43:00 (67.169.141.86)
I've posted on this subject quite a bit. My take is that the Touch analog outs are quite good and can sound REALLY good if you use it correctly. My experience has been that the sound is fairly suscept .......
237: Computer Audio Asylum, RE: What do you think about Audio-gd DACs with PCM1704UK chips? (0.00)
Posted by John Swenson on 2010-07-11, 23:26:35 (67.169.141.86)
I was specifically referring to the dac19DSP. I think this is a very balanced device. The other more expensive ones start spending too much money on one specific aspect, without similar attention to o .......
238: Computer Audio Asylum, RE: What do you think about Audio-gd DACs with PCM1704UK chips? (0.00)
Posted by John Swenson on 2010-07-11, 05:54:55 (67.169.141.86)
First off let me say I have not heard one or seen one in person, just what I have seen on their web page. This design is almost exactly what I have built myself. These guys seem to have almost exactly .......
239: Computer Audio Asylum, RE: Next step to PC audio? (0.00)
Posted by John Swenson on 2010-07-01, 21:33:53 (67.169.141.86)
Hi Rick, what is the input impedance of the input the Touch is connected to? The output capacitor was not implemented correctly and I think how it sounds is going to be significantly affected by the l .......
240: Tweakers' Asylum, RE: Black sharpie works just as well as special green pens (0.00)
Posted by John Swenson on 2010-06-28, 21:20:59 (67.169.141.86)
Today thats probably true since most transports use either red or blue lasers. But in the early days when all CD players used infrared lasers it was NOT true. Many black inks were opaque to visible li .......
241: Tube DIY Asylum, RE: Pentode CCS with -80V/100mA supply avail ? (0.00)
Posted by John Swenson on 2010-06-26, 20:46:58 (67.169.141.86)
I would probably try an EL-509, but its definitely not a 9pin miniature. John S. .......
242: Computer Audio Asylum, RE: Logitech Touch Users - A Question... OK, Two... Maybe Three ;) (0.00)
Posted by John Swenson on 2010-06-26, 20:38:51 (67.169.141.86)
What ADC are you using? Does it have a recording level adjustment? If you don't have an adjustment you might be recording the LPs at too low a level. You can check that by zooming in on the waveform a .......
243: Computer Audio Asylum, RE: More Questions On The LogiTech Touch and Ripping (0.00)
Posted by John Swenson on 2010-06-26, 20:31:09 (67.169.141.86)
I use a program called WaveRepair to add cue points then write out a cue file. Sbqeezebox server can read the cue file and treats it as an album. WaveRepair also has an automatic track search feature .......
244: Tweakers' Asylum, RE: What do you suppose is in the green marker... (0.00)
Posted by John Swenson on 2010-06-23, 12:51:04 (67.169.141.86)
What these attempt to do is keep light from the laser getting out the edges of the CD. In the early days of CDs infrared lasers were used. The ink to use was critical because many formulations that we .......
245: Tube DIY Asylum, RE: Rectifier noise suppression (0.00)
Posted by John Swenson on 2010-06-23, 12:43:54 (67.169.141.86)
I ran tests on about 20 different transformers I had on hand and found that the 330 ohm .022uf was a good compromise that worked well on everything. I've used it on everything I do now with very good .......
246: Tube DIY Asylum, RE: Tube line preamplifier (0.00)
Posted by John Swenson on 2010-06-21, 23:10:32 (67.169.141.86)
If you want to try something really unusual take a look at my BDT preamp. This uses a Beam Deflection Tube (BDT) designed for use in a color TV sub carrier demodulator, but works great for audio. Its .......
247: Computer Audio Asylum, RE: it's not the math (0.00)
Posted by John Swenson on 2010-06-20, 17:16:33 (67.169.141.86)
Thanks for the post, very well said. In a very round about way I think it might actually be about the math. My current hypothesis is that a lot of software differences have to do with how much of the .......
248: Computer Audio Asylum, CEC belt drive transport (0.00)
Posted by John Swenson on 2010-06-20, 16:59:10 (67.169.141.86)
Years ago I heard a lot of buzz about the CEC belt drive transport and decided to try it. It was terrible. The music was flat, boring, lifeless, probably the worst sounding transport I'd ever heard. T .......
249: Tube DIY Asylum, RE: Rectifier noise suppression (0.00)
Posted by John Swenson on 2010-06-19, 21:49:41 (67.169.141.86)
Capacitors by themselves do not make good snubbers. You need some resistance to damp oscillations. The biggest resonance is in the transformer itself. The easiest way to damp this resonance is to put .......
250: Computer Audio Asylum, RE: RF Attenuators = Jitter Reducers? (0.00)
Posted by John Swenson on 2010-06-19, 16:01:45 (67.169.141.86)
I really doubt this is a general purpose solution. The output in question sounds like it is a AES/EBU over BNC output rather than an S/PDIF output. As mentioned thats what the crystal chips were actua .......
251: Tweakers' Asylum, RE: Best low-ohm power resistors? (0.00)
Posted by John Swenson on 2010-06-18, 13:17:30 (147.145.40.44)
My favorites are the Caddocks. They have several TO-220 style ones which go up to 50W (MP850). My favorite is the MP820, but you would need three in parallel. I'm not sure how 3X MP820 would sound as .......
252: Computer Audio Asylum, RE: Yellowtec PUC2 (0.00)
Posted by John Swenson on 2010-06-18, 12:58:36 (147.145.40.44)
I don't think there is such a thing. Bulk mode is always a two way protocol, the host sends data and waits for acknowledgment from the device. A bulk mode transfer cannot just shove data down the wire .......
253: Computer Audio Asylum, RE: Yellowtec PUC2 (0.00)
Posted by John Swenson on 2010-06-17, 13:43:26 (147.145.40.44)
Bulk transfers still have flow control. The host does not send more data until the device informs the host it has successfully received the data. Thus it is in essence asynchronous. A clock comming fr .......
254: Computer Audio Asylum, RE: Peachtree Nova, what bit rate will it's optical inputs accept? (0.00)
Posted by John Swenson on 2010-06-12, 20:49:23 (67.169.141.86)
Its good to 24/96 for sure. It MAY work up to 192 but thats problematical. The TOSLINK receivers theoretically don't have enough bandwidth to go up to 192, but you might find it works in some situatio .......
255: Tweakers' Asylum, RE: Damps the electromagnetic standing waves. (0.00)
Posted by John Swenson on 2010-06-07, 20:57:05 (67.169.141.86)
I think there is also mechanical damping as well. I've been doing a lot of work recently with thick aluminum enclosures etc. What I found was that the stiffness of the thick aluminum is high enough th .......
256: Computer Audio Asylum, RE: Help! with new Touch (0.00)
Posted by John Swenson on 2010-06-06, 21:31:45 (67.169.141.86)
Yes a full scan is imperative for proper functioning. At this point you want to look at the log files and see if there is anything that gives a clue as to what is happening. You can see the log file .......
257: Computer Audio Asylum, RE: Help! with new Touch (0.00)
Posted by John Swenson on 2010-06-05, 16:46:40 (67.169.141.86)
A first major question: I am not sure whether you are running an external server or the internal server? The internal server is used if you plug a USB drive into the Touch. In order to make it fit on .......
258: Computer Audio Asylum, RE: some of us don't like proprietary-like interfaces (0.00)
Posted by John Swenson on 2010-06-04, 10:38:16 (147.145.40.44)
I don't get this, Philips was designing an interface that its own chips would use to talk to each other on the same board. I'm sure the engineers never even had the concept of it being used directly a .......
259: Computer Audio Asylum, RE: Wavelength Crimson (0.00)
Posted by John Swenson on 2010-05-24, 23:55:03 (147.145.40.44)
What do you consider theoretical? I have a tube amp that I designed and built that runs at 25 watts per channel with zero feedback that runs at .03% distortion at 1watt and gets up to about .08% at 25 .......
260: Computer Audio Asylum, distortion (0.00)
Posted by John Swenson on 2010-05-24, 16:37:11 (147.145.40.44)
I think the article is referring to the active device by itself without using feedback. There are some tubes that have very low distortion if you use them in the proper range (voltage, current). Powe .......
261: Computer Audio Asylum, RE: Any comments on the Touch's Headphone Out? (0.00)
Posted by John Swenson on 2010-05-21, 12:45:15 (147.145.40.44)
The headphone out is good but not great. Taking the analog outs to a really good heaphone amp WILL be better. I listen to a Touch over the builtin headphone jack quite a bit and enjoy it very much. .......
262: Computer Audio Asylum, RE: That is a very interesting project. (0.00)
Posted by John Swenson on 2010-05-20, 11:59:49 (147.145.40.44)
This is not available yet, its still under development. John S. .......
263: Computer Audio Asylum, RE: Which DAC are you using? (0.00)
Posted by John Swenson on 2010-05-18, 17:38:08 (147.145.40.44)
My main system DAC is a prototype for the Bottlehead DAC which has a S/PDIF receiver and transmitter in an FPGA. Its designed to be used with interfaces that will sync their S/PDIF out to an input str .......
264: Computer Audio Asylum, RE: SB-Touch no display (0.00)
Posted by John Swenson on 2010-05-18, 17:13:42 (147.145.40.44)
Its a Freescale MX35 series, I don't remember which exact model, its sitting open on my bench right now so when I get home I can get out the magnifying goggles and look! The Touch has a bunch of /sys .......
265: Computer Audio Asylum, RE: SB-Touch no display (0.00)
Posted by John Swenson on 2010-05-17, 14:22:15 (147.145.40.44)
The screen off screensaver still leaves signals going to the display, but I'm sure you CAN turn off the signals to the display by setting certain registers in the CPU. This will probably have the same .......
266: Computer Audio Asylum, RE: SB-Touch no display (0.00)
Posted by John Swenson on 2010-05-16, 16:10:35 (67.169.141.86)
Just make a separate little board with the FPC connectors and the resistors. Plug the display into the new board and then use FFC jumpers from the new board to the main board. It would also make it mu .......
267: Computer Audio Asylum, RE: SB-Touch no display (0.00)
Posted by John Swenson on 2010-05-16, 16:03:15 (67.169.141.86)
No, the screen off screensaver just turns off the back light, the clock and sync signals are still going to the LCD. I tried the screen off mode and I couldn't hear any difference. But getting rid of .......
268: Computer Audio Asylum, RE: Soundwise are you talking about the Squeezbox analog outs or digital out? (0.00)
Posted by John Swenson on 2010-05-16, 15:56:08 (67.169.141.86)
This was through the analog outs. I did check it with digital to a Peachtree Nova and my own DAC. With the Nova there was a difference without display but not nearly as big a difference as with the a .......
269: Computer Audio Asylum, More tests (0.00)
Posted by John Swenson on 2010-05-16, 15:53:11 (67.169.141.86)
While I had the Touch opened up I decided to try bypassing the output caps. The DAC is already ground referenced so I'm not sure why those caps are even in there. I measured 4mV on the DAC output whic .......
270: Computer Audio Asylum, SB-Touch no display (0.00)
Posted by John Swenson on 2010-05-15, 22:44:27 (67.169.141.86)
Today I tried running my touch without a display, not just turned off, but with the display physically removed. It works! It plays music and can be controlled remotely. BUT you can't set it up after .......
271: Digital Drive, RE: Looking for a quality bnc chassis mount connector (0.00)
Posted by John Swenson on 2010-05-13, 23:53:09 (147.145.40.44)
Make sure you get a 75 ohm jack. The 50 ohm variety is much more common. If it doesn't specifically say 75ohm its almost certainly a 50 ohm part. There is going to be very little difference between BN .......
272: General Asylum, RE: Depends on what you mean by "critical listening" (0.00)
Posted by John Swenson on 2010-05-13, 15:25:37 (147.145.40.44)
I tend to do very little type 1 listening, I have a hard time doing anything when music is going on, the music grabs my attention. That leaves mostly type 2 and 3. I've been doing a lot less type 3 re .......
273: Computer Audio Asylum, RE: How do you set Squeezebox Server to convert FLAC to PCM? (0.00)
Posted by John Swenson on 2010-05-11, 12:50:10 (147.145.40.44)
The left column is the file type, the middle column is the stream type and the right column is the program used for the conversion. So this means that a flac will not get streamed as flac (its disable .......
274: Computer Audio Asylum, RE:John - Question Concerning SB-Touch (0.00)
Posted by John Swenson on 2010-05-11, 12:39:18 (147.145.40.44)
Yes I have used an external powered drive. The best sound is using an external server streaming PCM so transcoding flac or anything else to PCM in the server. Decoding on the Touch is not as good. Run .......
275: Computer Audio Asylum, RE: Best Adaptable OS for Audiophiles? (0.00)
Posted by John Swenson on 2010-05-09, 00:26:52 (67.169.141.86)
Here is my solution: the netjack chip, the network interface is all done with dedicated logic in an FPGA, not even a processor at all. It outputs I2S which can be reclocked by low jitter oscillators ( .......
276: Computer Audio Asylum, RE: Question Concerning SB-Touch (0.00)
Posted by John Swenson on 2010-05-08, 23:57:49 (67.169.141.86)
What I have found is that an external server sounds better than the internal server. An external server transcoding flac to PCM or sending wav as PCM sounds quite a bit better than decoding flac on th .......
277: Digital Drive, RE: RG59 coax used for cable TV is 75ohm (0.00)
Posted by John Swenson on 2010-05-07, 12:13:38 (147.145.40.44)
Yep, type F connectors work great and are cheap and readily available. They are a very good choice for building stuff yourself. And since they are only available in 75 ohms there is no possibility of .......
278: Digital Drive, RE: What About (0.00)
Posted by John Swenson on 2010-05-04, 17:15:19 (147.145.40.44)
The problem is BNCs are way too expensive for cheap consumer gear. I think the best bet would have been Type F connectors, WAY better than RCA, available all over the place and CHEAP. If they would ha .......
279: Digital Drive, RE: What About (0.00)
Posted by John Swenson on 2010-05-03, 10:48:21 (147.145.40.44)
I've posted on this a couple of times. If you are talking about AES/EBU digital connections I prefer a properly implemented S/PDIF coax with real 75 ohm connectors. The XLR connector is not a particu .......
280: Computer Audio Asylum, RE: What didn't you like about your experience with the Squeezebox Touch? (0.00)
Posted by John Swenson on 2010-05-02, 14:48:10 (147.145.40.44)
There most likely will be a new wave of third party applications starting to be developed soon. Until recently Logitech had a very restrictive license which concerned many of the third party developer .......
281: Computer Audio Asylum, RE: "USB power management chip...plugged in can't pull so much current it messes up the main system." (0.00)
Posted by John Swenson on 2010-05-02, 14:41:27 (147.145.40.44)
Of course thats not what I meant. The power supply is not a massive 500 watt supply, they want to make sure that what you plug into it is not going to pull the supply voltage down to the point that th .......
282: Computer Audio Asylum, RE: SB Touch USB power. (0.00)
Posted by John Swenson on 2010-04-30, 17:06:31 (147.145.40.44)
It is definitely a 500 mA port. There is a USB power management chip between the Touch's supply and the port, put there specifically so that what gets plugged in can't pull so much current it messes u .......
283: Computer Audio Asylum, Internal server details (0.00)
Posted by John Swenson on 2010-04-30, 16:59:54 (147.145.40.44)
If you use it with an external server it works very well, there are a lot of issues with running the internal server with a USB HD attached. The Touch just barely has enough memory to run the player .......
284: Computer Audio Asylum, RE: Squeezebox Touch analog out or coax into Onkyo SR876? (0.00)
Posted by John Swenson on 2010-04-27, 14:37:03 (147.145.40.44)
My experience has been that the analog outs from the Touch are much better than those from the SB3. The S/PDIF out is also quite a bit better. Whether analog from Touch is going to sound better than .......
285: Computer Audio Asylum, RE: usb vs rca (0.00)
Posted by John Swenson on 2010-04-20, 23:55:30 (67.169.141.86)
The issue is that in adaptive mode you have to have some form of variable clock that can track the input data rate. Variable clocks almost always have higher jitter than fixed clocks. Even devices suc .......
286: Computer Audio Asylum, RE:Analog volume control (0.00)
Posted by John Swenson on 2010-04-14, 13:51:07 (147.145.40.44)
Hmm, this brings up a whole new field of exploration, do you want a flexible shaft or a rigid one? Aluminum, titanium, carbon fiber? What to support it with, super precision ball bearings? Vibration d .......
287: Computer Audio Asylum, RE: Linux Question (0.00)
Posted by John Swenson on 2010-04-14, 13:37:17 (147.145.40.44)
It CAN be very stripped down. You need the kernel and kernel modules for any drivers you need that aren't compiled into the kernel, some form of initilization files to start things up at boot time, th .......
288: Tweakers' Asylum, RE: Diy Footers (0.00)
Posted by John Swenson on 2010-04-13, 15:29:23 (147.145.40.44)
I don't use footers at all. My speakers are suspended from the roof joists. The resonant frequency is less than 1/4 Hz. It does a very good job isolating in the horizontal plane, but its still fairly .......
289: Computer Audio Asylum, RE: Naive question - how is S/PDIF output improved? (0.00)
Posted by John Swenson on 2010-04-13, 15:14:24 (147.145.40.44)
The issue is that there is no such thing as a jitter immune DAC which takes its input from S/PDIF. Even ones built with the Sabre DACs which are supposed to be jitter immune are not. The number of DAC .......
290: Computer Audio Asylum, RE: MacMini direct vs streaming from Squeezebox. (0.00)
Posted by John Swenson on 2010-04-12, 14:18:45 (147.145.40.44)
No, the only way to do that is to open it up, take out the crystals and feed the same frequency clocks in from the external DAC. Unfortunately the Touch is much harder to open up than previous device .......
291: Computer Audio Asylum, RE: MacMini direct vs streaming from Squeezebox. (0.00)
Posted by John Swenson on 2010-04-12, 14:10:39 (147.145.40.44)
That July data is miscommunication. There was info from the European distributor saying 7/4/10 which is April 7 in European format. US people mis-interpreted that. The best way is to go to Logitech.c .......
292: Computer Audio Asylum, RE: MacMini direct vs streaming from Squeezebox. (0.00)
Posted by John Swenson on 2010-04-12, 14:01:52 (147.145.40.44)
It is running a real time kernel. The alsa interfaces are all hw (no plug). Definitely no ASRC. Standard two crystals which go through a pico gate mux then to two recolckers, one for the S/PDIF data .......
293: Computer Audio Asylum, RE: just ordered one (0.00)
Posted by John Swenson on 2010-04-11, 23:38:25 (67.169.141.86)
They have them in stock, they just want to take care of all the people who preordered them. New orders are supposed to start shipping Monday (tomorrow) which is when the website is supposed to say the .......
294: Computer Audio Asylum, RE: MacMini direct vs streaming from Squeezebox. (0.00)
Posted by John Swenson on 2010-04-11, 23:31:29 (67.169.141.86)
I'm not quite sure what you mean, the Squeezebox Touch box has very low emi out of its box and on all the wires going in and out. The jittor on its S/PDIF output is very low. Its outputs are either a .......
295: Computer Audio Asylum, RE: MacMini direct vs streaming from Squeezebox. (0.00)
Posted by John Swenson on 2010-04-11, 19:55:06 (67.169.141.86)
You haven't tried the Squeezebox Touch. The EMI is one of the lowest I have measured from a digital audio device and it can go to 24/96. (hardware wise it can go to 192, but the software needs some wo .......
296: Computer Audio Asylum, RE: My annoyance and goal: and thanks for your comments (0.00)
Posted by John Swenson on 2010-04-09, 12:02:18 (147.145.40.44)
Sure SBS and a Touch can display album art. As long as the album art is on the HD along with the music files it will display them on the Touch. It won't automatically go out on the net and grab album .......
297: Computer Audio Asylum, RE: Thank you, appreciate your time and answers: SBS (0.00)
Posted by John Swenson on 2010-04-08, 12:35:14 (147.145.40.44)
SBS is software, its written in perl so it will run on just about anything with a perl interpreter, it will run fine on the G5. Just download it and install, at one point in the install it will ask if .......
298: Computer Audio Asylum, RE: Is the digital out really much better? (0.00)
Posted by John Swenson on 2010-04-08, 10:56:17 (147.145.40.44)
The digital out from the Touch is way better than that of a SB3 or Duet as is. I don't have a Boulder modified Duet to compare so I really don't know how it will stack up. I don't know all the details .......
299: Computer Audio Asylum, RE: USB / SD Card (0.00)
Posted by John Swenson on 2010-04-08, 10:47:35 (147.145.40.44)
I've used the USB input extensively, but I haven't actually tried the SD card. Ive run both USB "sticks" and USB drives, they work well. But realize that with a hard drive you are back in the situatio .......
300: Computer Audio Asylum, RE: Wireless Controller (0.00)
Posted by John Swenson on 2010-04-08, 10:37:15 (147.145.40.44)
I think the controller being refered to is the same controller used with the Duet. You can buy them separately and use it to control the Touch. It has a color screen but its NOT a touch screen, it has .......
301: Computer Audio Asylum, RE: Squeezebox Touch officially released (0.00)
Posted by John Swenson on 2010-04-08, 10:28:59 (147.145.40.44)
In order to use an iTunes database you still need a squeezebox server (SBS) that has access to the iTunes DB. SBS knows how to read an iTunes DB (including playlists). Its usually best if the SBS is .......
302: Computer Audio Asylum, RE: Squeezebox Touch officially released (0.00)
Posted by John Swenson on 2010-04-07, 21:41:43 (67.169.141.86)
The Touch consists of three parts (software wise that is), a controller, a player and a server. The controller part can control any other squeezebox on the network and it works very well for that. I f .......
303: Computer Audio Asylum, RE: What is the future for 192 kHz? (0.00)
Posted by John Swenson on 2010-04-07, 21:32:29 (67.169.141.86)
No, Logitech is not working on it, I'M working on it! The hardware can handle 192 just fine but the alsa drivers are not designed to go that fast. The source for these drivers are available and I have .......
304: Computer Audio Asylum, RE: Some iPad thoughts (0.00)
Posted by John Swenson on 2010-04-07, 17:35:34 (147.145.40.44)
I have an older HP tablet which gets a lot of use. My specific use is that laptops are literally a pain in the neck. I wear bifocals which are a major pain with laptops. The screen is too close for th .......
305: Computer Audio Asylum, Squeezebox Touch officially released (0.00)
Posted by John Swenson on 2010-04-07, 15:55:12 (147.145.40.44)
The looong awaited Squeezebox Touch was officially released today. Preoredered Touches should be shipped within the next day or two. I've been a beta tester of the Touch for about a year and think it .......
306: Computer Audio Asylum, RE: OT: but computer related (0.00)
Posted by John Swenson on 2010-04-02, 12:12:22 (67.169.141.86)
Aha, you might be right, all the PAM I've done was with bluetooth, that might be why even the RevA phones are slower than the dedicated data adapter. I'll have to try PAM with cable. John S. ::: TOPIC .......
307: Computer Audio Asylum, RE: OT: but computer related (0.00)
Posted by John Swenson on 2010-04-01, 14:40:48 (147.145.40.44)
Ahh Jacksonville OR I love that place, wonderful town! It should have decent 3G coverage from the major carriers. They all have USB data adapters that you can plug into your laptop and get an interne .......
308: Tweakers' Asylum, RE: Sort of PRACTICAL... (0.00)
Posted by John Swenson on 2010-03-31, 13:40:30 (147.145.40.44)
Wrong coast, I'm in California (Bay area). Yep it surprised me too, but its definitely audible. I was expecting some subtle changes but it was way more than that. To do this right it has to be built .......
309: Tube DIY Asylum, RE: Do (Why do) tube amps have problems driving "difficult" loads? (0.00)
Posted by John Swenson on 2010-03-31, 13:03:15 (147.145.40.44)
Sure an OPT can be designed to handle low impedance loads, the hard part is a wide impedance range. Take a traditional 300B SE design with a 3k:8 OPT. It works fine at 8, but at one that is a 375 load .......
310: Computer Audio Asylum, RE: difference between spdif, aes-ebu questions (0.00)
Posted by John Swenson on 2010-03-31, 11:53:56 (147.145.40.44)
I'll comment on the technical issues, how things sound is a whole different subject in which there are no absolutes such "this one is always better". The data format between S/PDIF and AES/EBU is almo .......
311: Tweakers' Asylum, RE: Sort of PRACTICAL... (0.00)
Posted by John Swenson on 2010-03-29, 18:02:08 (147.145.40.44)
I have done partial tests on jitter and audibility, but not official careful scientific study. What I have done is take a squeezebox (garden variety SB3) powered by a good linear supply (so the crud g .......
312: Tube DIY Asylum, Different type of snubber (0.00)
Posted by John Swenson on 2010-03-26, 15:08:48 (147.145.40.44)
What I have found works much better is a cap and resistor in series, the combination across the secondary. Jim Hagerman has a nice article on this on his web site. This damps the resonance of the tran .......
313: Cable Asylum, clarification (0.00)
Posted by John Swenson on 2010-03-25, 17:54:22 (147.145.40.44)
I'll try and make a clarification that I hope Steve will agree with. First off its important to make the distinction between audio signal ground and safety ground. Audio signal ground is the outer she .......
314: General Asylum, I have one (0.00)
Posted by John Swenson on 2010-03-25, 12:07:31 (147.145.40.44)
I've had such a system for several years now. There is a subtle difference. The power coming out of the inverter is significantly cleaner than that coming from the grid, so during a sunny day when the .......
315: MagneQuest/Peerless Forum, RE: Hank Murrow's 2A3 Amp *pics* (0.00)
Posted by John Swenson on 2010-03-24, 13:54:13 (147.145.40.44)
Hi paul, I just wanted to make sure my interpretation of the chassis correct. It looks like you are using the standard FPE side extrusions but stacking them, using the front and back panels to hold ev .......
316: Computer Audio Asylum, RE: BNC plug (0.00)
Posted by John Swenson on 2010-03-23, 12:23:46 (147.145.40.44)
If a manufacturer says they are using a true 75ohm RCA jack they are lying to you, there is no such thing. They might be using a piece of 75 ohm cable inside, but that doesn't mean the connector is 75 .......
317: Computer Audio Asylum, 50 ohm BNC? (0.00)
Posted by John Swenson on 2010-03-22, 12:11:41 (147.145.40.44)
Do you mean to say that when you pay extra to get a BNC S/PDIF output they use a 50 ohm connector?! Thats the sort of thing that makes my blood boil. I can understand less than perfect voltage regulat .......
318: Tube DIY Asylum, RE: Machine Work (0.00)
Posted by John Swenson on 2010-03-16, 23:20:29 (67.169.141.86)
I hope you don't mind a question on machining. A couple years ago I bought a small vertical milling machine, its a manual version, no CNC. It works fine but I don't really know how to use it. I tried .......
319: Tweakers' Asylum, RE: Update (0.00)
Posted by John Swenson on 2010-03-16, 13:29:46 (147.145.40.44)
I'm going to suggest a series of tests and measurements you can make on your own, no electrician or anybody else needed, I think the results from these will be a good underpinning for further discussi .......
320: Computer Audio Asylum, RE: emu usb0404 losing lock in linux (0.00)
Posted by John Swenson on 2010-03-16, 12:09:01 (147.145.40.44)
Alsa is a set of kernel modules so there is no userland process that is going to show up. Do you by any chance have pulseaudio turned on? One of the things it does is resample audio to match the hard .......
321: Computer Audio Asylum, RE: emu usb0404 losing lock in linux (0.00)
Posted by John Swenson on 2010-03-16, 11:57:19 (147.145.40.44)
Softsqueeze is a java app so it uses the java sound engine for talking to the hardware. I've never had much luck with this on linux (with ANY hardware). I highly recommend trying squeezeslave, it work .......
322: Digital Drive, RE: Some technical issues-ADD (0.00)
Posted by John Swenson on 2010-03-12, 12:44:26 (147.145.40.44)
Yes, 192 over TOSLINK is essentially a no go. They just don't have enough bandwidth for it. If you want to do 192 coax is the only way to do it (75 ohm BNC prefered of course!) John S. .......
323: Digital Drive, RE: Pro's and Con's About Going SPDIF From A to B to C (0.00)
Posted by John Swenson on 2010-03-11, 12:01:06 (147.145.40.44)
If you are using RCA connectors there probably will be some degradation with multiple devices. If you have 75ohm BNCs on everything its probably much less of an issue. Of course all this really depend .......
324: Digital Drive, Some technical issues (0.00)
Posted by John Swenson on 2010-03-11, 11:49:43 (147.145.40.44)
I think I'll inject some (hopefully helpful) technical explanations of whats going on. For the coax transmission method the most important factor is impedance matching from beginning to end. S/PDIF u .......
325: Computer Audio Asylum, RE: "Low Powered Pico"......... (0.00)
Posted by John Swenson on 2010-03-11, 10:57:51 (147.145.40.44)
There are three boxes in the system, FitPC, connected by USB cable to 0404, which has two TOSLINK cables to the DAC. The DAC sends out a S/PDIF stream (which is just zeros for the data) and receives t .......
326: Digital Drive, RE: Toslink or SPDIF (0.00)
Posted by John Swenson on 2010-03-10, 15:04:06 (147.145.40.44)
I know its picky, but using the terms incorrectly drives me crazy for some reason. S/PDIF is the data format, there are two physical transport mechanisms defined: coax and optical. Both coax and optic .......
327: Tube DIY Asylum, RE: Class of Operation (0.00)
Posted by John Swenson on 2010-03-10, 14:00:25 (147.145.40.44)
I built a 211 amp that runs positive grid at all times, driven by a high transconductance pentode in CF configuration. The output impedance was low enough that it worked well driving the 211. The cont .......
328: Tube DIY Asylum, RE: tube circuit design: is there anything new? (0.00)
Posted by John Swenson on 2010-03-10, 12:33:25 (147.145.40.44)
Well I have the BDT preamp which uses a color TV subcarrier demodulator tube as an audio amplifier, using that tube in this way is new but the basic functioning of the circuit is not, its a simple pus .......
329: Computer Audio Asylum, RE: "Low Powered Pico"......... (0.00)
Posted by John Swenson on 2010-03-10, 12:19:04 (147.145.40.44)
No the 0404 is not modded, its setup in the external sync mode, this synchronizes the S/PDIF out to the S/PDIF in (coax or optical). The 0404 uses an asynchronous USB interface so this sort of thing i .......
330: Tweakers' Asylum, RE: NO (0.00)
Posted by John Swenson on 2010-03-10, 12:07:32 (147.145.40.44)
Well there is old school technology for this called the motor generator set (MG set for short) which can easily handle thousands of watts. They are kind of large mechanical beasts, the well built one .......
331: Computer Audio Asylum, RE: "Low Powered Pico"......... (0.00)
Posted by John Swenson on 2010-03-09, 12:51:18 (147.145.40.44)
I'm most likely going to be connecting the Touch with LVDS. John S. .......
332: Computer Audio Asylum, RE: How are you guys measuring the "pollution"?? (0.00)
Posted by John Swenson on 2010-03-08, 16:51:52 (147.145.40.44)
I don't know about DR but I use a spectrum analyzer connected to a probe with a 1" piece of wire sticking out the end. You can see the spectrum vary wildly as you move the wire around different boxes, .......
333: Computer Audio Asylum, RE: "Low Powered Pico"......... (0.00)
Posted by John Swenson on 2010-03-08, 11:16:14 (147.145.40.44)
I like the FitPC slim. I run it without a hard drive at all, I boot puppy linux off a USB stick, its designed so the whole OS runs off a ramdisk so the USB stick is only accessed at boot time. I run w .......
334: Tweakers' Asylum, RE: Long ordeal = long post. Sorry. (0.00)
Posted by John Swenson on 2010-03-05, 14:24:58 (147.145.40.44)
That DC voltage measurement is probably a critical piece to the puzzle. I just want to nail down exactly what you measured, from what to what. You had the system running, playing music and it was soun .......
335: Tube DIY Asylum, RE: question of power supply capacitor value (0.00)
Posted by John Swenson on 2010-03-04, 17:29:34 (147.145.40.44)
Recovery from transients in the music. I looked at the waveforms of a lot of the recorded music I like to listen to the best and saw lots of short transients sticking up above the "average" level of t .......
336: Tube DIY Asylum, RE: question of power supply capacitor value (0.00)
Posted by John Swenson on 2010-03-04, 17:08:28 (147.145.40.44)
What I meant was that as the caps get larger the space of designs that meets my requirements gets smaller, so its harder to find a solution that meets all the requirements. John S. .......
337: Tube DIY Asylum, RE: question of power supply capacitor value (0.00)
Posted by John Swenson on 2010-03-03, 12:29:17 (147.145.40.44)
I think its for more complex than just a simple small is good large is bad approach. All the components in the PS form a series of interconnected resonances and the total behavior of those resonances .......
338: Computer Audio Asylum, RE: follow up -- GREAT (0.00)
Posted by John Swenson on 2010-03-01, 05:37:34 (67.169.141.86)
Great going, I didn't think you had fried anything, it just needed to be connected properly. Have fun! John S. .......
339: Computer Audio Asylum, RE: clarification and pictures (0.00)
Posted by John Swenson on 2010-02-26, 13:09:25 (147.145.40.44)
Hi Radu, now I understand what you are trying to do. You are using an HTPC case as box to hold audio stuff, not a computer. What I would do: ignore the color coding of the cable, who knows what it is .......
340: Computer Audio Asylum, RE: Squeezebox Touch current status (0.00)
Posted by John Swenson on 2010-02-25, 18:18:00 (147.145.40.44)
I'm one of the beta testers so see a little more than most as to whats happening with the Touch. There are two main classes of issues now: how to configure the builtin server and what happens when you .......
341: Tube DIY Asylum, Pulsar (0.00)
Posted by John Swenson on 2010-02-24, 17:09:10 (147.145.40.44)
These are the guys that started it. They have a whole system with their own transfer paper and laminator to make it work well. This system is far and away better than any of the other techniques I hav .......
342: Computer Audio Asylum, RE: USB wiring color coding - connecting to I2S USB receiver (0.00)
Posted by John Swenson on 2010-02-24, 15:00:04 (147.145.40.44)
Hi Radu, I think our biggest problem is understanding what you want to do, and what you have already done. My understanding is that you have the USB->I2S board sitting completely inside your case, and .......
343: Computer Audio Asylum, RE: I2S ground noise issues & possible resolutions (0.00)
Posted by John Swenson on 2010-02-24, 14:38:44 (147.145.40.44)
This is an interesting tradeoff. One of the problems with S/PDIF (either form) is that the conventional receivers still have a PLL tracking the incoming signal. That PLL still generates ground noise i .......
344: Digital Drive, Thermal aspects of digital circuits and sound quality (0.00)
Posted by John Swenson on 2010-02-23, 17:32:10 (147.145.40.44)
I have talked about this several times so it has been addressed, but probably in obscure posts over in PC audio. I have done extensive listening tests at different temperatures on different chips and .......
345: Tube DIY Asylum, RE: 1:1 Bifilar Push-Pull Interstage Transformer? (0.00)
Posted by John Swenson on 2010-02-23, 15:59:37 (147.145.40.44)
The Lundahl LL1660PP seems just about right. But I also second the recommendation to try Dave Slagle, he will design you something for exactly your requirement. I went from using a pair of LL1660 to .......
346: Tube DIY Asylum, RE: Would a choke made especially for choke input PS provide less hum than a "regular" choke used for choke i (0.00)
Posted by John Swenson on 2010-02-23, 15:20:51 (147.145.40.44)
The critical issue is core saturation of the choke. The magnetic field in the choke comes from current flowing through the coil, when it gets too large the core "saturates" and all kinds of bad things .......
347: Computer Audio Asylum, RE: I2S ground noise issues & possible resolutions (0.00)
Posted by John Swenson on 2010-02-23, 11:02:48 (147.145.40.44)
There is no official voltage spec for I2S, the spec is the data format. Older chips use 5V signals and newer ones use 3.3V. In many cases the 3.3V will work with the 5V chips, but feeding 5V into a 3. .......
348: Computer Audio Asylum, RE: I2S ground noise issues & possible resolutions (0.00)
Posted by John Swenson on 2010-02-23, 10:19:17 (147.145.40.44)
The spec sheet is very misleading on this, it says its 2.0 compliant but it only goes up to full speed mode. What this means is that it will work with a 2.0 port, but it will not work in high speed m .......
349: MagneQuest/Peerless Forum, RE: Ping mqracing and John Swenson (0.00)
Posted by John Swenson on 2010-02-22, 10:50:58 (147.145.40.44)
Wow, someones going to build one of these! The distortion canceling circuit is now obsolete. I have a much simpler circuit which works just as well (actually better) and does not need any tweaking. .......
350: MagneQuest/Peerless Forum, RE: Hank Murrow's Phono Preamp (0.00)
Posted by John Swenson on 2010-02-19, 17:38:04 (147.145.40.44)
Hi Paul, what finish did you use for the front and back panels? It looks more polished than the standard anodized aluminum finish from FPE. I'm in the middle of doing several FPE designs right now, i .......
351: Computer Audio Asylum, RE: LED is be (0.00)
Posted by John Swenson on 2010-02-19, 13:06:45 (147.145.40.44)
LED on/off times are much slower than laser diodes, but are still much faster than is needed for digital audio transmission, its the rest of the circuitry around them that determines the "speed". The .......
352: Digital Drive, RE: wow - so many choices! (0.00)
Posted by John Swenson on 2010-02-18, 12:58:02 (147.145.40.44)
I would go with the M2Tech Hiface. Its really well designed and implemented. No its not the absolute best known to mankind, but for the price its exceptionally good. John S. .......
353: Computer Audio Asylum, RE: Toslink Connection to the DAC......... (0.00)
Posted by John Swenson on 2010-02-17, 11:33:50 (147.145.40.44)
A 2.0 port can handle all of the 1.1 speeds plus the high speed mode, so they are perfectly happy running with devices using full speed mode (the max under 1.1). I guess that in the early days of 2.0 .......
354: General Asylum, Surprise live music (0.00)
Posted by John Swenson on 2010-02-16, 19:48:48 (67.169.141.86)
Tonight my wife and I went to a local pizza joint and saw a bunch of music stands in the corner and were wondering what was going on. It turned out to be a Boy Scout band playing tonight. This was not .......
355: Tube DIY Asylum, RE: How to build a decent HT supply? (0.00)
Posted by John Swenson on 2010-02-16, 16:26:12 (147.145.40.44)
I've built many supplies right around what you are aiming at. It IS actually possible to achieve very good regulation and fairly low rectifier current with sub critical circuits. My current version us .......
356: Computer Audio Asylum, RE: And beware of Gamma Rays... (0.00)
Posted by John Swenson on 2010-02-16, 13:30:27 (147.145.40.44)
Its not the actual gamma rays, they get stopped by the gas molecules in the upper atmosphere. The gamma rays split apart the gas atoms which release a shower of particles, some of which go towards the .......
357: Computer Audio Asylum, RE: I'd rather ask you manufacturers to beef up the immunity of the gear so we don't have to worry about it. (0.00)
Posted by John Swenson on 2010-02-16, 12:28:56 (147.145.40.44)
It may not be as simple as you think (or hope). Adding a very high level of immunity to external influences over an extremely wide bandwidth to all inputs and from the space in general is neither easy .......
358: Computer Audio Asylum, Optical! (0.00)
Posted by John Swenson on 2010-02-16, 10:57:59 (147.145.40.44)
We just have to invent the audiophile approved optical wireless interface. Each room you want to use wireless in has in IR transponder mounted on the ceiling which are cabled to the wired LAN (we coul .......
359: Computer Audio Asylum, RE: Rice cooker (0.00)
Posted by John Swenson on 2010-02-16, 10:38:26 (147.145.40.44)
I also use a microwave rice cooker, it works great. But I did find I have to calibrate it to a particular microwave. Last year my wife bought a new microwave and the first batch of rice was terrible! .......
360: Computer Audio Asylum, RE: Well I'll Be......... (0.00)
Posted by John Swenson on 2010-02-16, 10:21:39 (147.145.40.44)
Hi Todd, these have been around for a long time, I bought one 5 or so years ago. I've posted several reviews here. They are available in long lengths as well (I have the 10 meter version) which are g .......
361: Computer Audio Asylum, RE: Toslink Connection to the DAC......... (0.00)
Posted by John Swenson on 2010-02-16, 10:16:34 (147.145.40.44)
The EMU 040USB will not work with the Optics cable, its only good for up to full speed mode and the 0404 uses high speed mode. The description is a little misleading, it says it will work with a USB .......
362: Computer Audio Asylum, RE: issues with Linux,,, (0.00)
Posted by John Swenson on 2010-02-10, 11:48:29 (147.145.40.44)
Thats great, I'll have to upgrade. I updated everything not long ago and I must have just missed the latest release. I'm using the external sync over S/PDIF feature which will be really nice to have .......
363: Computer Audio Asylum, RE: issues with Linux,,, (0.00)
Posted by John Swenson on 2010-02-09, 18:07:17 (147.145.40.44)
The problem here is that the 0404USB is not officially supported under linux. It just so happens that it sort of works sometimes maybe using the generic USB driver. The trick is that you have to use .......
364: Computer Audio Asylum, RE: Consider a Vortexbox (0.00)
Posted by John Swenson on 2010-02-09, 13:43:03 (147.145.40.44)
I heartily second the vortexbox! It has to be by far the easiest way to get a Squeezebox Server up and running, its already loaded, just copy the files over and start running. Its also a VERY capable .......
365: Computer Audio Asylum, RE: John: just noticed your name in Feb Sterophile... (0.00)
Posted by John Swenson on 2010-02-03, 10:14:20 (147.145.40.44)
Not that I know of! The name is fairly common so I'm sure its someone else. John S. .......
366: Tube DIY Asylum, RE: how did you take the measurement (0.00)
Posted by John Swenson on 2010-02-02, 14:23:25 (147.145.40.44)
I used a 10x probe and connected it between gnd and the cathode of the tube. When working with high voltage circuits I always used the clip tip of the probe, make sure its got a good connection to the .......
367: Computer Audio Asylum, RE: How do I eliminate pop and buzz in my system (0.00)
Posted by John Swenson on 2010-02-02, 12:32:04 (147.145.40.44)
Is this part of a video system? Do you have a cable TV box connected to the system in ANY way? I'm asking this because its very common to have buzz in systems connected to the cable. The cable itself .......
368: Tube DIY Asylum, RE: Grid stopper (0.00)
Posted by John Swenson on 2010-02-01, 15:38:05 (147.145.40.44)
I've had exactly the situation being discussed. I had a power amp I built that was humming fairly loudly, nothing I did would stop it. I tried all kinds ground loop schemes, shielding etc and nothing .......
369: Digital Drive, RE: any thoughts on this ebay DAC kits? (0.00)
Posted by John Swenson on 2010-01-27, 15:50:36 (147.145.40.44)
First off the disclaimers: I have not heard either of these specific boards, this is just based on having listened to many similar implementations, so there is basis for my recomendations, but it come .......
370: General Asylum, RE: Check out these amplifiers (0.00)
Posted by John Swenson on 2010-01-27, 13:05:16 (147.145.40.44)
From the description they are replacing a number of garden variety (cheap) components with much more expensive (high end) ones that supposedly make it sound much better. These modifications are almost .......
371: Computer Audio Asylum, RE: Sound Quality of External Drives (0.00)
Posted by John Swenson on 2010-01-26, 12:48:34 (147.145.40.44)
Noise on power supply lines can cause IM distortion with the audio signal producing enharmonic distortion products. The higher frequency products tend to fall in areas the ear is more sensitive to and .......
372: Computer Audio Asylum, RE: John, additional question on Touch (0.00)
Posted by John Swenson on 2010-01-21, 12:18:21 (147.145.40.44)
Yes I have used the Touch directly into an amp, actually most of my listening has been that way. The volume control works well, I have not had any sonic degradations from using the Touch's digital dom .......
373: Computer Audio Asylum, RE: Logitech Transporter Alternatives? (0.00)
Posted by John Swenson on 2010-01-20, 16:26:37 (147.145.40.44)
The Touch S/PDIF is superb. The transporter is the only SB product that out of the box can be synched to an external clock source. For use with the lessloss DAC the Duet might be the best choice. It .......
374: Computer Audio Asylum, RE: Logitech Transporter Alternatives? (0.00)
Posted by John Swenson on 2010-01-19, 08:47:38 (67.169.141.86)
I'm a beta tester for the Touch, I've been listening to it for a long time now. The sound quality from the Touch is WAY better than previous Squeezeboxen. Personally I think it even sounds better than .......
375: Digital Drive, RE: PCM1704UK vs Sabre DACs (0.00)
Posted by John Swenson on 2010-01-17, 23:28:40 (67.169.141.86)
They are somewhat apples to oranges. The Sabre comes with a built in ASRC and complex digital filter system. The 1704 has no digital filter. If you want to use it with a digital filter you have to sup .......
376: Computer Audio Asylum, RE: asus (0.00)
Posted by John Swenson on 2010-01-15, 12:56:11 (147.145.40.44)
Hi Howard, can you give us a little more such as what OS, application you are using to play the music etc. What file are you playing? Are you sure the file is in stereo? When you say mono what do you .......
377: Computer Audio Asylum, RE: iTunes/Amarra/Apple remote vs. Squeezeboxserver/SBR/iPeng ? (0.00)
Posted by John Swenson on 2010-01-15, 12:24:43 (147.145.40.44)
Hi Soundchekk I don't have experience with the Mac side of things, but I am doing exactly what you are talking about with the Squeezebox except I'm using an SB3. I have a DIY DAC with local very low j .......
378: Computer Audio Asylum, Squeezebox Touch (0.00)
Posted by John Swenson on 2010-01-09, 10:47:51 (147.145.40.44)
You might want to consider the Squeezebox Touch.The squeezebox line has traditionally been designed as network streamers requiring an external server, but the Touch has its own (slimmed down) server. .......
379: Computer Audio Asylum, RE: Moving parts vs. no moving parts (0.00)
Posted by John Swenson on 2010-01-06, 13:08:43 (147.145.40.44)
I've done a 4 layer board for the iGLX before, but it did not have the PCI, which adds a lot more connections, so it would probably need to be at least a 6 layer board. Its not a very big board so per .......
380: Computer Audio Asylum, RE: Looking For Help. (0.00)
Posted by John Swenson on 2010-01-05, 20:34:55 (147.145.40.44)
Hi Brian, don't give up hope yet. In many cases the processes that are causing these glitches are started at boot time and just sit around causing problems. MANY programs today install part of themsel .......
381: Computer Audio Asylum, RE: Moving parts vs. no moving parts (0.00)
Posted by John Swenson on 2010-01-05, 19:45:59 (147.145.40.44)
Aha! Recently I built something that might work instead. It was based on an old EPIA motherboard (you can still get new ones on ebay). These have a PCI connector so you can put a FW card in them. Trad .......
382: Computer Audio Asylum, RE: Moving parts vs. no moving parts (0.00)
Posted by John Swenson on 2010-01-05, 17:23:04 (147.145.40.44)
What happened to the Fit-PC? John S. .......
383: Computer Audio Asylum, RE: Network Induced Jitter (0.00)
Posted by John Swenson on 2010-01-01, 16:25:40 (67.169.141.86)
I have to jump in here. DR what you are talking about here does of course exist. There will be differences in arrival times from packet to packet, thats the way general purpose networks work. If its b .......
384: Computer Audio Asylum, RE: The First DUMB Question Of The New Year (0.00)
Posted by John Swenson on 2010-01-01, 15:29:51 (67.169.141.86)
You sold a G-11 and ST-2000!! What are you replacing them with? I have a GM-8, 5" Mak-Newt and starlight express camera, your "old" setup is bit up from mine, I can't imagine what you are going to upg .......
385: Computer Audio Asylum, RE: Mic Preamp Devices Into Windows Laptop (0.00)
Posted by John Swenson on 2010-01-01, 07:48:10 (67.169.141.86)
The EMU 0404-USB is quite popular for recording purposes. It has two fairly good mic inputs with phantom power. Its externally powered so you need a plug to plug it into. It can record up to 24/192. T .......
386: MagneQuest/Peerless Forum, RE: DAC Output Stage - a few questions on implementation! (0.00)
Posted by John Swenson on 2009-12-31, 09:25:01 (67.169.141.86)
Hi Mike, real quick comments, the DAC is balanced out, the easiest way to deal with this is a transformer. I don't think MQ makes one thats appropriate, Lundahl does. Over in KK they have a purely pas .......
387: Tube DIY Asylum, RE: When stacking power supplies.... (0.00)
Posted by John Swenson on 2009-12-27, 17:56:18 (147.145.40.44)
Jeff, for my 813 amp I have tried both the 866 and Cree Schotky and eventually settled on the Crees. The problem with the 866 route was that I could not get enough 866 with similar parameters for the .......
388: Computer Audio Asylum, RE: Boulder Digital Mods to my Squeezebox Duet or wait for SB Touch? (0.00)
Posted by John Swenson on 2009-12-27, 02:37:32 (67.169.141.86)
I think the Touch digital out is probably going to be better than the modded SBR. I don't have the Boulder modded SBR but from what I have read about it and what I have measured/heard from the Touch I .......
389: Computer Audio Asylum, RE: You're On the Right Track........ (With a Minor Quibble) (0.00)
Posted by John Swenson on 2009-12-27, 02:31:57 (67.169.141.86)
Hi Todd, when I'm talking about higher sampling rates I'm referring to 24/192 etc not the oversampling ratio. I agree with you my favorite oversampling ratio is 4X. Yes with 24/192 you can do a good .......
390: Computer Audio Asylum, RE: How close to vinyl quality can we get with PCM digital using a computer at home? (0.00)
Posted by John Swenson on 2009-12-26, 06:32:00 (208.106.127.79)
Hi DBB, I'll share some experiences of mine along these lines. I too have some LPs tghat are just amazing (certainly not all of them) that even with the ritual and problems sounded better than anythin .......
391: Tube DIY Asylum, Merry Christmas Fellow Tube Nutz (0.00)
Posted by John Swenson on 2009-12-25, 08:03:07 (67.169.141.86)
Ahhh the glow of thoriated tungsten on a Christmas morning.... We can't have a fire here, but the glow from the 813s and the beautiful music are wonderful. Merry Christmas to all. John S. .......
392: Computer Audio Asylum, RE: Replacing an M-Audio USB Audiophile (0.00)
Posted by John Swenson on 2009-12-21, 06:09:49 (67.169.141.86)
The analog inputs on the EMU 0404USB are "combo" XLR, you can plug in either an XLR (including 48V phantom for condenser mics) or a 1/4" plug. To get line level RCA in you use a RCA to 1/4" adapter. .......
393: Computer Audio Asylum, Squeezebox tests (0.00)
Posted by John Swenson on 2009-12-20, 17:44:31 (67.169.141.86)
There are a group of people who have been doing some of these tests over in the squeezebox forums concerning claims of sonic differences between decoding PCM or flac encoded streams. Several people ha .......
394: Tube DIY Asylum, RE: Peak output voltage levels for CD players (0.00)
Posted by John Swenson on 2009-12-16, 13:45:17 (147.145.40.44)
The official CD spec is 2V RMS at 0dBFS. (5.7V p-p). DACs are another matter. They range all over the place. Maybe about half of them try and stick with the 2V RMS standard, the rest are somewhere bet .......
395: Computer Audio Asylum, RE: SB-Touch coax-to-XLR cable....Problem Solved (0.00)
Posted by John Swenson on 2009-12-13, 17:09:59 (147.145.40.44)
Yes you could have a series of adapters and go from one box to the other without any "cable" involved. On the server question, yes you can run Squeeszebox Server on a NAS processor so there is no need .......
396: Tweakers' Asylum, RE: Is there any trick to solder wires on the legs of very small surface mount IC... (0.00)
Posted by John Swenson on 2009-12-12, 14:00:34 (147.145.40.44)
I always use 30 ga wire wrap wire for this sort of thing. As fmak mentioned the best way is to try and find an via or other part on the trace. On many boards the wire wrap wire will go through the hol .......
397: Computer Audio Asylum, RE: SB-Touch coax-to-XLR cable....Problem Solved (0.00)
Posted by John Swenson on 2009-12-12, 12:43:09 (147.145.40.44)
These actually do work. My recommendation is to get one with a plug end that will fit directly into the DAC, do not use a XLR - XLR cable between the transformer and the jack. The XLR connectors are h .......
398: Computer Audio Asylum, RE: Replacing laptop 12VDC power supply with something better? (0.00)
Posted by John Swenson on 2009-12-11, 16:24:01 (147.145.40.44)
I posted a design here back in January (09) for a nice 12V supply which should work well for your laptop. It uses a choke in the design but no tube rectifiers. Getting tube rectifiers with enough curr .......
399: Tube DIY Asylum, RE: Why EL34? (0.00)
Posted by John Swenson on 2009-12-06, 16:26:39 (147.145.40.44)
I haven't used a D3a, but I have used an EL84 very successfully. I tend to like to keep my D3as for critical signal circuits since I don't have very many so something like a CCS gets an EL84. If you h .......
400: Tube DIY Asylum, RE: Pentode CCS help.... (0.00)
Posted by John Swenson on 2009-12-06, 16:18:48 (147.145.40.44)
You can always use a resistor and VR tube(s). I've done this before and it works very well. And you now have TWO more tubes on top! You can always use the Gary Pimm CCS with pentode if you want to dis .......
401: Computer Audio Asylum, RE: I've lost gapless play on my Fit-PC2 with linux Mint (0.00)
Posted by John Swenson on 2009-12-05, 12:00:33 (147.145.40.44)
My first guess is that you might have something like pulseaudio running which is intercepting the stream and might be causing the issues.In your setup I don't think you need anything like pulseaudio s .......
402: Tweakers' Asylum, RE: No, you are just experiencing the effects of electrical resonance. (0.00)
Posted by John Swenson on 2009-12-04, 12:32:36 (147.145.40.44)
Hmmm, vibration on cables.... makes me wonder if the effect of cable risers is really vibration control rather than having to do with electric fields as is commonly stated. By providing a few specific .......
403: Computer Audio Asylum, RE: Cable effects same regardless of USB mode (0.00)
Posted by John Swenson on 2009-12-02, 14:53:01 (147.145.40.44)
Yes, the best async implementation will be better than the best adaptive. The adaptive doesn't have to be as bad as you mention, the local clock does not have to be slaved directly to the frame. It c .......
404: Computer Audio Asylum, RE: Cable effects same regardless of USB mode (0.00)
Posted by John Swenson on 2009-12-02, 12:11:57 (147.145.40.44)
Essentially yes. Both cases have two clocks in the DAC, the "USB clock" which runs at the USB bus frequency and gets data off the bus, and the "audio clock" which pulls audio data out of the buffer. I .......
405: Computer Audio Asylum, RE: What length usb sounds best, in your experience?nt (0.00)
Posted by John Swenson on 2009-12-02, 12:01:00 (147.145.40.44)
In general short cables sound better than long cables. Thats not an absolute, its possible to have a 4ft very good cable sound better than a cheap 3ft cable, but that cheap 3ft cable is probably going .......
406: Isolation Ward, RE: Foodstuffs - To use or not to use (0.00)
Posted by John Swenson on 2009-12-02, 00:42:33 (67.169.141.86)
I have a record clamp which has a flat surface (well tempered record player upgrade platter and clamp) and tried putting many things on top of it, they all changed the sound. Most made it worse but a .......
407: Computer Audio Asylum, RE: Cable effects same regardless of USB mode (0.00)
Posted by John Swenson on 2009-11-30, 15:47:48 (147.145.40.44)
The problem is ground noise coupling between boards (or "independant" sections on the same board). It is possible to setup the grounding schemes to minimize this, albeit not very easy. The easiest way .......
408: Computer Audio Asylum, RE: Cable effects same regardless of USB mode (0.00)
Posted by John Swenson on 2009-11-30, 13:18:47 (147.145.40.44)
I'd like to amplify some of these points and give some examples. Then I'll cover some of the differences between how these work with adaptive and asynchronous modes. The assumption I see that many pe .......
409: Computer Audio Asylum, RE: A challenge to all the hardware "experts" (0.00)
Posted by John Swenson on 2009-11-23, 14:48:27 (147.145.40.44)
I know I've been trying for a long time to do this. There is one place where some form of isolation seems to happen: data sent over ethernet. Two different scenarios that I have experimented with exte .......
410: Computer Audio Asylum, USB DACs (inexpensive) (0.00)
Posted by John Swenson on 2009-11-20, 14:17:40 (147.145.40.44)
A USB DAC would work, there are several well regarded ones in your price range. The USB spec says the wire can be up to 15 feet so you should be able to use it. The ultimate sound quality of many USB .......
411: Computer Audio Asylum, RE: Robert I knew what you are using! I was curious to know (0.00)
Posted by John Swenson on 2009-11-19, 14:32:29 (147.145.40.44)
The one I most recently put in my big computer was an ASUS, I don't remember the model number off the top of my head. I was very impressed by this board, the power regulators were quite clean with a l .......
412: Computer Audio Asylum, RE: Thank you John! (0.00)
Posted by John Swenson on 2009-11-17, 23:39:29 (67.169.141.86)
I don't recommend this approach, many of the regulators, especially the high current ones are not self contained devices but are a combination of a high power pass transistor, controler chip and caps, .......
413: Computer Audio Asylum, RE: PCI sound card digital versus analog output (0.00)
Posted by John Swenson on 2009-11-17, 12:28:13 (147.145.40.44)
I actually liked the MontegoII much better than the Santa Cruz. The Santa Cruz hard more channels and more fancy features but I thought the MontegoII sounded much better. I think I have 5 montegoIIs. .......
414: Computer Audio Asylum, RE: "Undervolting" MoBo power rails? (0.00)
Posted by John Swenson on 2009-11-17, 12:04:05 (147.145.40.44)
How the current responds with voltage change depends on what its driving. IF its driving CMOS chips directly (no regulator in between) then the current will go down with decreasing voltage. If it driv .......
415: Computer Audio Asylum, RE: Sound Cards w/RCA connections......... (0.00)
Posted by John Swenson on 2009-11-14, 12:15:50 (147.145.40.44)
The M-audio audiophile 2496 card has RCAs on the card for in and out. John S. .......
416: Computer Audio Asylum, RE: Toslink, mini connectors and the sad state of Mac audio... (0.00)
Posted by John Swenson on 2009-11-14, 01:18:20 (67.169.141.86)
Fry's is nerd heaven, they are HUGE stores, they sell computers and computer parts to build your own, but they also sell a large range of electronics parts. Typically about a third of the store is co .......
417: Digital Drive, pseudo balanced (0.00)
Posted by John Swenson on 2009-11-13, 16:58:10 (147.145.40.44)
There actually is a pseudo balanced connection, it uses a balanced connector with signal on one pin and the other pin has a connection to ground with the same impedance as the driven pin. This means t .......
418: Computer Audio Asylum, RE: Best way to get SPDIF to a 16/44.1 DAC - Squeezebox Touch or Fit-Pc NetJacked sending USB to Spdif convert (0.00)
Posted by John Swenson on 2009-11-13, 14:33:56 (147.145.40.44)
This is a very interesting question, the offramp driven from a fitpc 1 running netjack is very good, but so is the S/PDIF from the Touch. I haven't actually done a direct comparison of the S/PDIF, I h .......
419: Computer Audio Asylum, RE: Toslink, mini connectors and the sad state of Mac audio... (0.00)
Posted by John Swenson on 2009-11-12, 17:20:54 (147.145.40.44)
I can attest to the decline of toslink. I'm using toslink in my latest DAC (two of them, one in one out, soundcard syncs to one) and needed to get some toslink cables. I went over to Fry's and couldn' .......
420: Tweakers' Asylum, RE: Question about AC inputs / AC outputs of bridge rectifier (0.00)
Posted by John Swenson on 2009-11-12, 16:22:20 (147.145.40.44)
I think we are all trying to figure out exactly what you mean. Lets start with a transformer, say 12V AC on the secondary. You have two wires coming out. Those two wires get connected to the AC termi .......
421: Tweakers' Asylum, RE: Advice re IKEA Lack rack (0.00)
Posted by John Swenson on 2009-11-12, 13:37:50 (147.145.40.44)
The whole purpose of the lack rack is to have a low mass but stiff system, filling it with sand negates all that. The expanding foam is a much better approach, it increases rigidity without adding muc .......
422: Tweakers' Asylum, RE: REVIEW: Vanguard 24.576MHz TCXO Passive Components (0.00)
Posted by John Swenson on 2009-11-12, 13:16:49 (147.145.40.44)
I'm having trouble understanding this. Is the circuit designed for a fixed frequency or a variable frequency oscillator? If its designed for a VCXO (variable frequency) then its implementing a narrow .......
423: Computer Audio Asylum, RE: Yes, quite frustrating....INDEED! (0.00)
Posted by John Swenson on 2009-11-11, 12:44:44 (147.145.40.44)
The analog is via standard electrical contacts that touch the outside diameter of the standard 3.5mm plug. The digital is via optical that in the jack sits right at the very tip of the plug. When yo .......
424: Computer Audio Asylum, RE: Sheeva Plug as music server (0.00)
Posted by John Swenson on 2009-11-10, 14:50:02 (147.145.40.44)
A number of people over on the squeezebox furums have posted instructions on how to do this. John S. .......
425: Computer Audio Asylum, RE: Test of Server vs. USB drive vs. Laptop hard drive (0.00)
Posted by John Swenson on 2009-11-10, 11:17:11 (147.145.40.44)
As carcas posted there are technical reasons for this. The offramp is an adaptive USB interface which is still affected by timing issues on the USB bus. Its a very well implemented adaptive interface, .......
426: Computer Audio Asylum, RE: Test of Server vs. USB drive vs. Laptop hard drive (0.00)
Posted by John Swenson on 2009-11-09, 18:42:29 (147.145.40.44)
I'm not quite sure of your setup. It sounds like you have a laptop with a USB to S/PDIF interface going to some form of DAC (I don't think you specified it). It sounds like the laptop was running JRi .......
427: Computer Audio Asylum, RE: What kind of recording?.... (0.00)
Posted by John Swenson on 2009-11-06, 14:10:50 (147.145.40.44)
Hi David, I sing in several choirs and have been recording our concerts for 30 years now, I know exactly what you are talking about! One thing to add to your list is to make sure you turn off all scr .......
428: Computer Audio Asylum, RE: Shielding in DIY htpc case (0.00)
Posted by John Swenson on 2009-11-06, 11:00:20 (147.145.40.44)
I would say yes, go for the shielding if you can. As Fred says at least provide room for it if you don't want to implement it up front. Another advantage of the system is by using a PCI riser card it .......
429: Computer Audio Asylum, RE: Is this the right forum for asking questions about music servers? (0.00)
Posted by John Swenson on 2009-11-03, 23:43:37 (67.169.141.86)
Hi Bryan, for a multi-room system I really like the squeezebox system. There are many different hardware players that can be controlled with many different methods. You can use the Mac-Mini, the sque .......
430: Computer Audio Asylum, RE: Is this the right forum for asking questions about music servers? (0.00)
Posted by John Swenson on 2009-11-02, 18:54:28 (147.145.40.44)
Lets see if I can shed some light here. There are several parts to a computer music system: The music files have to be stored on a disk somewhere. This can be a disk in a computer, or it can be a disk .......
431: Digital Drive, RE: Why No World Clock Function For So Many DAC's??? (0.00)
Posted by John Swenson on 2009-10-31, 13:16:04 (67.169.141.86)
I don't doubt it. As I said the jitter of the local clock in a fair amount of pro gear is not very good. So using an external clock even with all its problems could still wind up sounding better. Fro .......
432: Digital Drive, RE: Why No World Clock Function For So Many DAC's??? (0.00)
Posted by John Swenson on 2009-10-30, 16:14:54 (147.145.40.44)
Are you talking about word clock in or work clock out? Word clock out can get complicated. Sending the clock out is easy. You also need a way to switch over to the internal clock from the receiver gen .......
433: Computer Audio Asylum, RE: It doesn't work-please help (0.00)
Posted by John Swenson on 2009-10-30, 15:28:24 (147.145.40.44)
You are on the right track with the audio device in the control panel. The one you want is High Definition Audio (HDA) this is the onboard audio chip that drives the jacks you are plugging into. Alte .......
434: Computer Audio Asylum, RE: Squeezebox 2 analog out verses digital out (0.00)
Posted by John Swenson on 2009-10-29, 14:52:38 (147.145.40.44)
I don't have an SB2 but I do have several SB3s. For me the analog outs are not that great, not BAD but not great either. With a really good external DAC the digital out can sound much better than the .......
435: Computer Audio Asylum, RE: SqueezeBox system (0.00)
Posted by John Swenson on 2009-10-28, 23:51:20 (67.169.141.86)
Probably the best NAS box to use with Squeezebox stuff is the VortexBox. Its $359 (on Amazon) for a 1TB box and comes with SqueezeBox Server preloaded. It DOES have a DVD drive for ripping CDs (with g .......
436: Computer Audio Asylum, RE: SqueezeBox system (0.00)
Posted by John Swenson on 2009-10-28, 15:27:49 (147.145.40.44)
I recommend the squeezebox line for you. The server software can run on many NAS boxes. The transporter that was mentioned in another response is the "High End" squeezebox designed specifically for au .......
437: Computer Audio Asylum, RE: System on USB flash drive... Any meaningful comparisons, sound quality-wise? (0.00)
Posted by John Swenson on 2009-10-28, 15:05:58 (147.145.40.44)
No its not ready yet. Puppy has gone through several itterations and netjack is being redone right now. Its hard to keep up! I did put together a version with a RT kernel and netjack and tried to get .......
438: Computer Audio Asylum, RE: System on USB flash drive... Any meaningful comparisons, sound quality-wise? (0.00)
Posted by John Swenson on 2009-10-27, 15:49:32 (147.145.40.44)
The way I run my low power linux systems is with either a USB flash stick or IDE flash module to boot linux, but its building a ramdisk and putting everything in the ramdisk. So once its booted the fl .......
439: Computer Audio Asylum, RE: It would still be async, it just would require a driver. (0.00)
Posted by John Swenson on 2009-10-27, 11:24:31 (147.145.40.44)
Its still true. Its just that the Musiland is running in high speed mode which has enough bandwidth so even a lower priority device gets plenty of bandwidth even for high res audio. The priority issu .......
440: Computer Audio Asylum, RE: Big advantage? (0.00)
Posted by John Swenson on 2009-10-27, 10:53:18 (147.145.40.44)
To me at least what is weird is there are a number of boxes that DO implement async mode but use a PLL based frequency synthesizer for the local clock which has far worse jitter than if they had just .......
441: Digital Drive, RE: thanks for the excellent posts. (0.00)
Posted by John Swenson on 2009-10-26, 13:56:54 (147.145.40.44)
Hi Bill, my problem with the way say MPD does things is that you are doing file IO at the DAC end. This is much more complex than decoding the netjack stream requiring a processor and maybe an OS. Onc .......
442: Digital Drive, RE: Excellent post! Thank you and one quibble. (0.00)
Posted by John Swenson on 2009-10-26, 00:33:23 (67.169.141.86)
Here's my whole line of reasoning on this: I don't like having a computer in or anywhere near my audio rack. They generate EMI, vibrations, noise etc. Of course you can build fanless no moving part co .......
443: Digital Drive, RE: Just strip the clock and regenerate (0.00)
Posted by John Swenson on 2009-10-25, 15:57:19 (67.169.141.86)
But how do you regenerate a clock and achieve jitter as low as a good low jitter fixed frequency oscillator? John S. .......
444: Digital Drive, RE: You don't hear much here about Firewire having async and adaptive flavors (0.00)
Posted by John Swenson on 2009-10-24, 23:05:14 (67.169.141.86)
I've had three firewire devices over the years (I'm not listing them here) and every one of them has had abysmal jitter, the cheap little 2706 USB DACs I made had much lower jitter! So firewire is not .......
445: Digital Drive, RE: Excellent post! Thank you and one quibble. (0.00)
Posted by John Swenson on 2009-10-24, 22:57:35 (67.169.141.86)
Hi Charles, unfortunately nothing I have designed has actually made it to production yet. Hopefully the Bottlehead DAC will be the first. On the ethernet front the system I am envisioning uses the ne .......
446: Digital Drive, Some thoughts on async etc. (0.00)
Posted by John Swenson on 2009-10-24, 15:23:20 (67.169.141.86)
I'm going to take a stab at this and hopefully do it in a nice even handed way. Lets tackle the USB/I2S point first. There is a conceptual difference here, USB is a computer bus, it is a way to get da .......
447: Computer Audio Asylum, RE: new queezebox touch as quaility computer to spdif only (0.00)
Posted by John Swenson on 2009-10-24, 03:45:22 (67.169.141.86)
The touch is not shipping yet so nobody is modding them yet. It will be a while after people have them before the modders start working with them. John S. .......
448: Computer Audio Asylum, RE: new queezebox touch as quaility computer to spdif only (0.00)
Posted by John Swenson on 2009-10-23, 12:30:32 (147.145.40.44)
The Touch definitely uses an asynchronous protocol to the server. It has its own local crystal oscillators (one for 44.1 and 88.2 and the other for 48 and 96). I'm not sure what you mean by "reclocke .......
449: Tube DIY Asylum, RE: Ping DanL (0.00)
Posted by John Swenson on 2009-10-22, 17:43:49 (147.145.40.44)
I did a lot of testing on this a year or so ago with a scope and spectrum analyzer, I DID find a measurable correlation with power cords. It has to do with transformer resonances in the range of 100KH .......
450: MagneQuest/Peerless Forum, RE: Diff CCS schematic (0.00)
Posted by John Swenson on 2009-10-22, 16:32:02 (147.145.40.44)
Hi John, the idea here is to use the tradition differential topology which has a single CCS connected to both cathodes. The circuit I came up with gives you that but lets you adjust the voltage offset .......
451: Tube DIY Asylum, RE: Like it or not: (0.00)
Posted by John Swenson on 2009-10-20, 18:22:21 (147.145.40.44)
Well I'm using a 813 pentode, single ended with zero feedback and getting 0.1% THD at 18 watts. So it is possible to get somewhat low distortion even with pentodes without feedback. Then again its a v .......
452: MagneQuest/Peerless Forum, Diff CCS schematic (0.00)
Posted by John Swenson on 2009-10-18, 23:42:43 (67.169.141.86)
OK, I finally drew it up. Here is the schematic for the adjustable differential CCS. Its essentially a standard Gary Pimm SBCCS with an extra differential cascode. The voltage offset for each cathode .......
453: Computer Audio Asylum, RE: Just Pre-Ordered the Squeezebox touch, and a thought about their USB port (0.00)
Posted by John Swenson on 2009-10-18, 23:27:49 (67.169.141.86)
I'm not completely sure. The radio, touch and controler all run essentially the same application package (with of course tweaks for the individual device) The Touch runs that on top of a real linux ke .......
454: Computer Audio Asylum, RE: Just Pre-Ordered the Squeezebox touch, and a thought about their USB port (0.00)
Posted by John Swenson on 2009-10-18, 06:53:33 (67.169.141.86)
I'm the person who has done the touch USB audio work. My experience is that Touch USB audio is very good but not quite up there with the best. For example its not quite as good as a FitPC slim with st .......
455: Tube DIY Asylum, RE: What about Caddock's Micronox film? (nt) (0.00)
Posted by John Swenson on 2009-10-15, 17:10:35 (147.145.40.44)
I've found Caddocks to be very good sounding particularly in situations where they have a DC bias current such as a plate or cathode resistor. John S. .......
456: Computer Audio Asylum, RE: Never say Never (0.00)
Posted by John Swenson on 2009-10-15, 16:52:04 (147.145.40.44)
You probably have to be root to do this. If you want to see what the switches are just do: iecset -c 1 it will list all the iec settings. Do the usual aplay -l to find out which card is the one you w .......
457: Computer Audio Asylum, RE: Never say Never (0.00)
Posted by John Swenson on 2009-10-15, 16:07:42 (147.145.40.44)
Hi DR, its great you got that working. The problem is there are iec958 "switches" in the drivers that are usually off by default. Unfortunately the alsamixer approach to setting these is extremely un .......
458: Computer Audio Asylum, RE: apples and oranges (0.00)
Posted by John Swenson on 2009-10-15, 13:52:34 (147.145.40.44)
If you have one of Gordon's or the Ayre DAC this is a way to use it with the squeeze system. It increases your options in setting up a system. John S. .......
459: Computer Audio Asylum, RE: USB port would not support Audio on the Touch (0.00)
Posted by John Swenson on 2009-10-15, 13:44:03 (147.145.40.44)
Hi Gordon, I've plugged USB DACs into the port and played music over them so I can guarantee that at least for the one that I have it does in fact play music to a USB DAC plugged into the USB port. Lo .......
460: Computer Audio Asylum, RE: apples and oranges (0.00)
Posted by John Swenson on 2009-10-14, 17:43:18 (147.145.40.44)
Yes, right now exactly the same thing goes to all connected outputs (DAC, S/PDIF, USB). Currently the way its setup is there is no way to have volume on DAC and max on S/PDIF as you can on the SB3, it .......
461: Computer Audio Asylum, RE: apples and oranges (0.00)
Posted by John Swenson on 2009-10-14, 14:10:26 (147.145.40.44)
It DOES work very well driving a USB DAC, its just not automatic right now. See my reply to Steve for details. A couple weeks ago I posted a detailed report on my experience with the Touch including u .......
462: Computer Audio Asylum, RE: apples and oranges (0.00)
Posted by John Swenson on 2009-10-14, 14:06:38 (147.145.40.44)
The USB port on the Touch works very well feeding a USB DAC. I've done it myself with several dacs including your interface. It sounds very good with all the DACs I've used, close to the best host I'v .......
463: Computer Audio Asylum, RE: Squeezebox Touch vs. Off-Ramp 3 (0.00)
Posted by John Swenson on 2009-10-14, 00:10:57 (67.169.141.86)
I don't think anybody on the planet actually has both of those to make a direct comparison. I have a touch and an earlier version of the Off Ramp circuit. There is a bit of a problem with the compari .......
464: Computer Audio Asylum, RE: apples and oranges (0.00)
Posted by John Swenson on 2009-10-13, 23:54:19 (67.169.141.86)
I think its a perfectly valid question, what is the sound quality of a DAC connected to the S/PDIF out of an Off Ramp and what is the sound quality of the same DAC connected to the S/PDIF out of the T .......
465: Computer Audio Asylum, RE: The sample rate issue... (0.00)
Posted by John Swenson on 2009-10-13, 23:45:24 (67.169.141.86)
netjack handles the clock in DAC very well as long as the interface to the computer can handle it. The rate at which the "soundcard" pulls the data out of the buffer determines the rate at which the m .......
466: Computer Audio Asylum, RE: Playing with MPD over netjack (long) (0.00)
Posted by John Swenson on 2009-10-13, 23:30:30 (67.169.141.86)
Here is the option for specifying auto connect: jack_load netmanager -i "-c" This works very nicely as long as the server just has one set of physical ports. (the machine can have multiple soundcards, .......
467: Computer Audio Asylum, RE: Playing with MPD over netjack (long) (0.00)
Posted by John Swenson on 2009-10-13, 17:34:53 (147.145.40.44)
If I'm remote connecting its usually just ssh, I hardly ever use vnc. If I want the Full Graphical Experience I just connect screen and keyboard. John S. .......
468: Computer Audio Asylum, RE: Playing with MPD over netjack (long) (0.00)
Posted by John Swenson on 2009-10-13, 13:43:21 (147.145.40.44)
I do a lot of headless linux systems. I deal with this by having a small LCD display and keyboard with a builtin trackball that can plugin when needed. I have grub setup to boot by default in console .......
469: Computer Audio Asylum, RE: Playing with MPD over netjack (long) (0.00)
Posted by John Swenson on 2009-10-13, 13:33:27 (147.145.40.44)
Hi Alan, if you are using 1.9.2 or 1.9.3 there is an auto connect option for netjack that will automatically connect the netjack ports to the physical ports on the master jack server. I don't think it .......
470: Bottlehead Forum, RE: Some general questions about setting it up (0.00)
Posted by John Swenson on 2009-10-13, 12:15:27 (147.145.40.44)
If you want up to 24/192 cards such as the Juli@ and the EMU 1212M will work well. If you only want to go to 24/96 the EMU 0404-USB can be used as well. There is also a new tiny little USB Edirol UA- .......
471: Bottlehead Forum, RE: Thoughts on upcoming DAC (0.00)
Posted by John Swenson on 2009-10-13, 08:10:07 (67.169.141.86)
1. The DAC is NOS (No oversampling, no digital filter) 2. There will be some analog filtering, carefully worked out gentle filtering after the DAC chip can radically improve the sound of a NOS DAC. Th .......
472: Computer Audio Asylum, RE: Correction: Wav versus Flac (0.00)
Posted by John Swenson on 2009-10-09, 15:01:30 (147.145.40.44)
Its the same thing. Wav is PCM data in a file with a simple header. So when it says its sending PCM its sending exactly the same data as is in the wav file, its just stripping off the wav header, whic .......
473: MagneQuest/Peerless Forum, RE: Adjustable balance differential CCS (0.00)
Posted by John Swenson on 2009-10-09, 10:56:22 (147.145.40.44)
I have yet another variant of this, last night I worked out a CCS design based on Gary Pimm's CCS that can be used for a differential amp but still allows for adjusting the current between tubes. With .......
474: Computer Audio Asylum, RE: not Streaming (0.00)
Posted by John Swenson on 2009-10-07, 13:42:50 (147.145.40.44)
Thats not true, async USB sends the data in exactly the same way as other USB audio modes. The difference is an extra connection going between DAC and the computer that tells the computer to speed up .......
475: Computer Audio Asylum, RE: Looks like you've rattled the lemming cage (0.00)
Posted by John Swenson on 2009-10-07, 12:06:15 (147.145.40.44)
Hi Dave, thats a very good overview of the subject. One interesting result is that as you get to a very low overhead system small changes in the system can make what appear to be large changes in soun .......
476: Computer Audio Asylum, RE: HD vibrations- how to decouple ? (0.00)
Posted by John Swenson on 2009-10-06, 17:45:15 (147.145.40.44)
How much tension do you put on the bungee cords? I can envision fairly significant differences depending on the tension. I can just see it now, audiophile bungee cords! John S. .......
477: Computer Audio Asylum, Low power linux boxes (0.00)
Posted by John Swenson on 2009-10-05, 13:12:13 (147.145.40.44)
This week I just built a low power fanless system based on a EPIA motherboard (the ME6000G to be exact). Even though its a very old design they still make them, I got mine on ebay for $39 (brand new, .......
478: Computer Audio Asylum, RE: Same issue with other RAID arrays... (0.00)
Posted by John Swenson on 2009-10-05, 12:26:22 (147.145.40.44)
This was a major concern of mine when I setup my RAID array. I decided to go with a linux server using standard linux software RAID. The fact that it had been around for awhile and most likely will be .......
479: Bottlehead Forum, RE: Quickie as DAC I/V output stage? (0.00)
Posted by John Swenson on 2009-10-02, 18:00:45 (147.145.40.44)
Not directly. The DSD1796 has a balanced output of 4mA PP to make full use of that you need some form of differential input which the quickie does not have. You COULD use just one side, but that only .......
480: Computer Audio Asylum, RE: Inguz plugin (0.00)
Posted by John Swenson on 2009-10-01, 18:02:05 (147.145.40.44)
Most of the plugin writers have created repositories that contain their latest creations. The squeezebox website has an extensive list of these somewhere in the wiki. I'm pretty sure I remember Inguz .......
481: Digital Drive, RE: High end DAC w/ Squeezebox (0.00)
Posted by John Swenson on 2009-10-01, 13:31:26 (147.145.40.44)
24/96 works for the internal DAC, S/PDIF both coax and TOSLINK, and for a USB DAC connected to the USB port (if the DAC supports 24/96!). The only thing that doesn't do 24/96 is the little tiny speak .......
482: Computer Audio Asylum, RE: I've been running it for months (0.00)
Posted by John Swenson on 2009-10-01, 13:19:08 (147.145.40.44)
Me too. I've been running various versions of 7.4 with the touch and my regular SBs. Besides the look of the controller (BIG changes there), the one thing that caught me by surprise was how plugins an .......
483: Tube DIY Asylum, RE: ))I'd LOVE to hear an SET amp that doesn't ... (0.00)
Posted by John Swenson on 2009-09-28, 15:51:44 (147.145.40.44)
Well my 813 amp is SE (SEP not SET) with the 813 as a cascode element (grounded grid mode). Its designed for 30 watts, but I've only measured it up to 18 watts (its not very sensitive and the source i .......
484: Digital Drive, More info on DAC needed (0.00)
Posted by John Swenson on 2009-09-28, 13:32:53 (147.145.40.44)
First before looking for clocks we need to know what you are clocking! Is this a box that takes an external clock? If so is it a word clock or "super clock"? What type of connector? What Impedance? H .......
485: Digital Drive, RE: High end DAC w/ Squeezebox (0.00)
Posted by John Swenson on 2009-09-28, 12:48:11 (147.145.40.44)
Both the SB3 and touch have separate crystals for 44.1 and 48 families. The ones in the Touch are little lower in jitter but not by a very large amount. Both the SB3 and Touch have a "clock mux", this .......
486: Digital Drive, RE: High end DAC w/ Squeezebox (0.00)
Posted by John Swenson on 2009-09-25, 13:08:35 (147.145.40.44)
The new SqueezeBox Touch has a much better S/PDIF out than the SB3 and it supports up to 24/96. Its been announced but not available yet (sometime in December). I'm a beta tester of the touch and ha .......
487: Tube DIY Asylum, RE: Power Supply testing in the Real World? Suggestions needed (0.00)
Posted by John Swenson on 2009-09-25, 10:49:39 (147.145.40.44)
I do something very similar, I built an "amp simulator" which is a high voltage high current N channel MOSFET attached to a big heatsink. I feed the drain of the MOSFET from a power resistor fed from .......
488: Digital Drive, RE: An amazingly lucid description for laymen! (0.00)
Posted by John Swenson on 2009-09-17, 13:14:12 (147.145.40.44)
Hi Charles, you must be using Digital Filter Design software. That list is straight out of the marketing slide. Did you try implementing the same (well at least similar) function with different numbe .......
489: Computer Audio Asylum, RE: Linux Digital Out Issue (0.00)
Posted by John Swenson on 2009-09-16, 23:44:06 (67.169.141.86)
What "soundcard" is it? Many of them use subdevice 1 as the S/PDIF out so if your soundcard is card 1 connecting to the S/PDIF would be: plughw:1,1 Always try plug first, it might only accept 24 bit s .......
490: Tube DIY Asylum, ParaUltrafeed (0.00)
Posted by John Swenson on 2009-09-15, 00:07:28 (67.169.141.86)
How about ParaUltraFeed? Given the CCS on the plate I don't think its even going to be ultrapath. My understanding is that Ultrapath bypasses the cathode resistor to B+. The CCS is going to force the .......
491: Tube DIY Asylum, RE: Pentode Pimm CCS or not? (0.00)
Posted by John Swenson on 2009-09-14, 13:45:31 (147.145.40.44)
Thats a long answer! The advantage of the pentode version is that tubes are designed to get hot and handle high voltages, if you have a lot of power to dissipater and or high voltage range to deal wit .......
492: Tube DIY Asylum, RE: CCS comparisons? (0.00)
Posted by John Swenson on 2009-09-13, 23:59:04 (67.169.141.86)
I've tried all but the IXYS. First off, the commonly referred to Gary Pimm CCSs don't use the IXYS, where did you find a design of his that uses this? All the ones I know of use enhancement mode Nchan .......
493: General Asylum, RE: Desperate for advice please! (0.00)
Posted by John Swenson on 2009-09-12, 06:20:44 (67.169.141.86)
Hi Maggie, the A'Divas are what are called "satellite" speakers, you use them in a system with a subwoofer and two satellites (they "orbit" around the sub). This concept has been around for a long tim .......
494: Tube DIY Asylum, Cathode cap (0.00)
Posted by John Swenson on 2009-09-11, 16:19:06 (147.145.40.44)
A cathode resistor bypass cap in this circuit actually does nothing. Because there is a constant current going into the plate there will be a constant current coming out of the cathode. With a constan .......
495: General Asylum, A bit unusual recommendation (0.00)
Posted by John Swenson on 2009-09-11, 13:39:53 (147.145.40.44)
Hi Maggie, I'm going to recommend something a bit out of the ordinary but I think they will work amazingly well for you, and both the companies have dealers in Dubai. For the speakers I would go with .......
496: Computer Audio Asylum, RE: I found the perfect speaker wires for your system! (0.00)
Posted by John Swenson on 2009-09-10, 16:49:43 (147.145.40.44)
Well of course it will sound good, it has a Delta impedance matching circuit! John S. .......
497: Tweakers' Asylum, RE: Heat sink pads? (0.00)
Posted by John Swenson on 2009-09-09, 15:57:44 (147.145.40.44)
If they are soft and flexible you don't need grease. It makes things much easier to assemble! John S. .......
498: Computer Audio Asylum, RE: Computer recommendations: Buy or build (0.00)
Posted by John Swenson on 2009-09-09, 13:01:52 (147.145.40.44)
I love Hauptwerk! Fantastic software, I only wish it worked on linux. What you need depends on how you are going to use it. Lots of memory is always a good thing, get as much as you possibly can. (of .......
499: Tube DIY Asylum, RE: 6.0 ohm? (0.00)
Posted by John Swenson on 2009-09-08, 16:42:22 (147.145.40.44)
Ooops, you are right, I slipped a decimal point there. John S. .......
500: Computer Audio Asylum, RE: Sounds like a great low cost solution for Windows (0.00)
Posted by John Swenson on 2009-09-08, 12:05:07 (147.145.40.44)
My guess is they are not using any of the standard audio protocols but using one of the builtin ezusb modes. IF this is correct then you probably won't find anything already existing that would work f .......
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