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1: General Asylum, I've often wondered how much improvement can be made too. (0.00)
Posted by Ralph on 2024-03-20, 08:15:02 (75.168.114.39)
But so far since the early 1980s its continued to happen. Class D has continued to improve too, despite being an older technology, most if its improvements have occurred in the last 20 years. ::: TOP .......
2: Speaker Asylum, My guess is you want a constant current source that can make 250mA (0.00)
Posted by Ralph on 2024-03-20, 08:06:59 (75.168.114.39)
And to do that into a load like this you'll need a supply of about 80V. So I'd build a power supply that can do that, with an adjustable constant current source that is reliable with 500mA. A DC Ammet .......
3: OTL Asylum, Not exactly. (0.00)
Posted by Ralph on 2024-03-20, 08:00:13 (75.168.114.39)
Usually the output transformer is the bandwidth limit of any tube amp, save for perhaps some tuning on the bottom end to reduce the possibility of saturation. The ZEROs convert from 16 Ohms down to 4 .......
4: Speaker Asylum, RYou might ask them what current they want to see nt (0.00)
Posted by Ralph on 2024-03-19, 14:19:27 (75.168.114.39)
- .......
5: General Asylum, If you don't have to filter the class D (0.00)
Posted by Ralph on 2024-03-19, 14:17:18 (75.168.114.39)
Then it can have problems with crossover distortion. I'm sure they sorted that out. Class D amps that use an output filter are immune to this problem. That DAC chip is pretty good, so there won't be .......
6: Amp/Preamp Asylum, +1 nt (0.00)
Posted by Ralph on 2024-03-19, 14:12:00 (75.168.114.39)
- .......
7: Speaker Asylum, Field coils usually want the right current rather than a voltage. (0.00)
Posted by Ralph on 2024-03-19, 11:30:29 (75.168.114.39)
The voltage occurs when you have the right current. I'm curious- what sort of field coil speaker takes that much voltage? Is it out of an old radio? .......
8: Amp/Preamp Asylum, Not for long if you keep playing it!! Follow these instructions to prevent failure. (0.00)
Posted by Ralph on 2024-03-19, 11:28:39 (75.168.114.39)
The hum is caused by aged filter capacitors in the power supply. They load the power transformer a lot more than they should. If you persist in running the amp as it is, the power transformer will bu .......
9: Amp/Preamp Asylum, Make sure you give those Sound Labs time to break in! (0.00)
Posted by Ralph on 2024-03-19, 11:23:40 (75.168.114.39)
Everything we've heard suggests that takes a while. So don't be upset if they don't totally bring home the bacon right away. I think we've already had the discussion about how solid state amps have t .......
10: General Asylum, No. (0.00)
Posted by Ralph on 2024-03-19, 11:20:20 (75.168.114.39)
If you want the most out of your amps and speakers, place the amps close to the speakers so as to minimize the speaker cable length. This is particularly true of lower impedance speakers. You can driv .......
11: OTL Asylum, Depends on the Maggies, but regardless you'll need a set of ZEROs (0.00)
Posted by Ralph on 2024-03-19, 11:15:12 (75.168.114.39)
for best results. We have customers using M-60s on the MG-1.7s and the like with good results. .......
12: OTL Asylum, I don't think so. (0.00)
Posted by Ralph on 2024-03-19, 11:12:36 (75.168.114.39)
The layout is entirely different, using different tubes. So its a different model. For example it appears to use a triode input tube rather than a pentode. .......
13: OTL Asylum, Apparently not the same amp nt (0.00)
Posted by Ralph on 2024-03-18, 12:35:52 (75.168.114.39)
- .......
14: Amp/Preamp Asylum, 'All the time' and 'with some amps' aren't exactly the same thing. (0.00)
Posted by Ralph on 2024-03-18, 12:20:21 (75.168.114.39)
Logically this says that the amps you do this with 'all the time' are of the kind that this can be done without harm and you don't use amps of any other topology. Clearly not the amps of to the topic .......
15: Critic's Corner, Yes, sometimes the intention to get things right is also expensive nt (0.00)
Posted by Ralph on 2024-03-15, 13:00:29 (75.168.143.89)
- .......
16: Amp/Preamp Asylum, Tube amps in general can have their output sections paralleled nt (0.00)
Posted by Ralph on 2024-03-15, 09:37:25 (75.168.143.89)
- .......
17: OTL Asylum, No photo, but if they didn't use ceramic sockets it would have been unreliable nt (0.00)
Posted by Ralph on 2024-03-15, 09:35:49 (75.168.143.89)
- .......
18: OTL Asylum, I doubt 6336s (0.00)
Posted by Ralph on 2024-03-14, 10:43:25 (75.168.143.89)
You need ceramic sockets for those! Since this was built by Luxman they would have used them if intended for that tube so 6080s is far more likely. .......
19: Amp/Preamp Asylum, You can't parallel the channels of an amp if it has solid state outputs. (0.00)
Posted by Ralph on 2024-03-14, 08:30:55 (75.168.143.89)
Bad Things happen. Don't do it! The amp could be modified so the two channels were one but you'd need an expert to do it. It is possible to do a bridge circuit with solid state, by driving one channe .......
20: OTL Asylum, RE: 1st tube appears to be a 12A*7 of some kind. (0.00)
Posted by Ralph on 2024-03-14, 08:22:15 (75.168.143.89)
Given the value of the plate loads (27K), I'm inclined to say 12AU7. So try that one there. If it does not light up, try a 6CG7. If pin 9 is grounded, then its a 6DJ8. If pins 4 and 5 are wired toget .......
21: OTL Asylum, This looks like a low power stereo OTL to me. (0.00)
Posted by Ralph on 2024-03-13, 14:17:20 (75.168.143.89)
So it has two RCA inputs and two speaker terminals. Therefore it uses four (6080) output tubes. Plus another 12BH7. A photo of the input section as big as the first one would be really helpful. ::: T .......
22: OTL Asylum, If they are going to oscillate, it will be load dependent. nt (0.00)
Posted by Ralph on 2024-03-13, 14:10:53 (75.168.143.89)
- .......
23: Tube DIY Asylum, I forgot about that- it complicates things. (0.00)
Posted by Ralph on 2024-02-15, 11:09:00 (75.168.143.89)
A good CCS has a nice high impedance, so you're probably right. Did you optimize the CCS to the operating point of the tube? I've found it useful to run a sine wave thru things just to verify that th .......
24: Tube DIY Asylum, 10uf isn't enough. (0.00)
Posted by Ralph on 2024-02-15, 09:17:09 (75.168.143.89)
As far as the bypass is concerned, the tube is in parallel with the 12k resistor. The more current you run the lower the impedance of the circuit; the larger the bypass needs to be. Otherwise it will .......
25: Tube DIY Asylum, RE: cathode follower plate voltage varies with current (0.00)
Posted by Ralph on 2024-02-14, 11:31:59 (75.168.143.89)
The more current the less plate voltage you can run. If playing that with the plate resistor, the plate load will affect the sound adversely. You'll want to put a capacitance to ground to bypass it; .......
26: Tubes Asylum, The further upstream the tube is in the signal chain, the more it affects the sound. nt (0.00)
Posted by Ralph on 2024-02-14, 11:24:54 (75.168.143.89)
g .......
27: Critic's Corner, FWIW: High end audio is not driven by price, its driven by intention. (0.00)
Posted by Ralph on 2024-02-09, 09:42:36 (75.168.143.89)
That is why you can have far less expensive gear outperform the higher priced spread, sometimes in every way. Often the higher prices are due to the Veblen Effect and nothing else (the manufacturer ha .......
28: Tube DIY Asylum, This circuit does not have a 'tail'. (0.00)
Posted by Ralph on 2024-02-09, 08:33:48 (75.168.143.89)
Will you elaborate a bit more on the need for an input transformer in absence of a CCS in the tail? Of course it helps to have a balanced input. But tubes are not perfect and neither is the power su .......
29: Tube DIY Asylum, Yeah, sorry about that. (0.00)
Posted by Ralph on 2024-02-08, 12:09:04 (75.168.143.89)
Your circuit is similar to the one at the link. You might want to take a look. There is a kit for it IIRC .......
30: Tube DIY Asylum, My mistake (0.00)
Posted by Ralph on 2024-02-08, 10:18:41 (75.168.143.89)
You got it right. The transformer presents about 13K load to your DAC with the dual 4.99K resistors. I don't know what I was thinking! .......
31: Tube DIY Asylum, take a look at this application document (0.00)
Posted by Ralph on 2024-02-08, 08:23:16 (75.168.143.89)
The values in it suggest that the values you are asking about are incorrect. .......
32: Cable Asylum, That depends! (0.00)
Posted by Ralph on 2024-02-07, 09:59:22 (75.168.143.89)
If the equipment supports AES48 going balanced will be noticeable as blacker backgrounds and overall a more musical and neutral presentation. Since you are running single-ended right now, I suspect t .......
33: Tube DIY Asylum, This circuit is balanced but not differential. (0.00)
Posted by Ralph on 2024-02-07, 09:56:31 (75.168.143.89)
So it needs an input transformer, otherwise you'll have no Common Mode Rejection Ratio (CMRR). Jensen Transformers makes good transformers for this sort of thing. I'd use a 49.9K plate load at a mini .......
34: Tube DIY Asylum, No problem running class A FWIW with your B+ nt (0.00)
Posted by Ralph on 2024-02-07, 09:42:56 (75.168.143.89)
= .......
35: Tube DIY Asylum, +1 nt (0.00)
Posted by Ralph on 2024-02-05, 15:06:00 (75.168.143.89)
= .......
36: Tube DIY Asylum, That's really not a problem! (0.00)
Posted by Ralph on 2024-02-02, 09:54:48 (75.168.105.246)
To keep an amplifier to having a good zero crossing, the output tubes have to be properly biased. The problem you have in the output transformer is the center tap is never actually centered. One solu .......
37: Amp/Preamp Asylum, Another FWIW- the Avantgardes were designed with solid state in mind. (0.00)
Posted by Ralph on 2024-01-30, 13:51:06 (75.168.105.246)
A class D amp can be quite good on them if you get the right one. I run a class D at home on my Classic Audio Loudspeakers, which are not as efficient, but employ midrange horns. They are very tube fr .......
38: Amp/Preamp Asylum, That photo is a hoax just FWIW. (0.00)
Posted by Ralph on 2024-01-30, 10:36:54 (75.168.105.246)
A mineral bath would make pretty quick work of any electronics submersed in it if it were energized. But there are class D amps now that are as good or better as the best tube amps (in the area of be .......
39: Amp/Preamp Asylum, RE: Yes, as long as too much gain is not asked of them, they'll be fine. nt (0.00)
Posted by Ralph on 2024-01-26, 11:04:03 (75.168.72.225)
- .......
40: Amp/Preamp Asylum, I would agree with that. (0.00)
Posted by Ralph on 2024-01-26, 08:49:47 (75.168.72.225)
The Crown lacks the Gain Bandwidth Product to be neutral at higher frequencies since the feedback drops off so distortion rises (causing brightness and harshness). But in the bass frequencies it shoul .......
41: Amp/Preamp Asylum, RE: Crown DC300A (0.00)
Posted by Ralph on 2024-01-25, 13:58:47 (75.168.72.225)
This was not a very pleasant amp to listen to at the best of times. Be careful when sourcing semiconductors for it. There are a lot of counterfeits on ebay that won't meet spec. As to servicing it, .......
42: OTL Asylum, A minor point :) (0.00)
Posted by Ralph on 2024-01-23, 11:39:20 (75.168.72.225)
Most OTLs are Atma-Sphere, which uses a Circlotron output. The Transcendent Sound uses a totem--pole output, similar to the Futterman. As I understand it, its a modification of the Futterman circuit. .......
43: Tube DIY Asylum, A proper OTL circuit :) (0.00)
Posted by Ralph on 2024-01-17, 10:04:11 (75.168.72.225)
You might take a look at this thread on DIYaudio.com. Variations of our circuit have been built using PL509s and the like. The Circlotron is a bit more stable circuit and allows for symmetrical drive .......
44: Tube DIY Asylum, I'd stay away from 6336s (0.00)
Posted by Ralph on 2024-01-17, 09:58:24 (75.168.72.225)
When they short, they can short hard. So you need more fuse considerations and the tube is rare. In addition, it must be operated with a ceramic socket else the socket will fail due to the heat. ::: .......
45: Tube DIY Asylum, To drive speakers you need current, so yes. (0.00)
Posted by Ralph on 2024-01-17, 09:56:40 (75.168.72.225)
- .......
46: Planar Speaker Asylum, RIP Jim. (0.00)
Posted by Ralph on 2024-01-17, 09:51:07 (75.168.72.225)
Jim was always very nice to me. He always made time for me at audio shows and if I had any questions. Always a gentleman. Back in 2020 a stolen bike of mine turned on Craigslist and his son spotted i .......
47: OTL Asylum, loss of transconductance (0.00)
Posted by Ralph on 2024-01-16, 14:06:18 (75.168.72.225)
Is what causes loss of output power, higher output impedance and increased distortion. If the load is benign this usually takes a long time. We had one customer who ran his amps (MA-1s) about 50,000 .......
48: Tube DIY Asylum, Yes- it needs to stay. But there's a bug in it. (0.00)
Posted by Ralph on 2024-01-15, 08:02:17 (75.168.72.225)
There should be a cap to ground off of the + input to the servo opamp; same value as the feedback cap on the - input. .......
49: OTL Asylum, The Chinese and Russian power tubes sound similar, (0.00)
Posted by Ralph on 2024-01-15, 07:53:11 (75.168.72.225)
- the American 6AS7G is supposed to sound a bit better (probably owing to making slightly more power) but are also tricky with reliability because they are not designed for fixed bias operation. So i .......
50: High Efficiency Speaker Asylum, 30' by 40' is a large room. (0.00)
Posted by Ralph on 2024-01-15, 07:20:55 (75.168.72.225)
My old listening space was 17' by 21' and most 'full range' single-driver loudspeakers would fall flat on their face trying to fill it at a a decent level. The reason to go with a 'full range driver' .......
51: Tube DIY Asylum, Yes +1 nt (0.00)
Posted by Ralph on 2024-01-12, 14:22:10 (75.168.72.225)
+1 .......
52: Tube DIY Asylum, Sorta. (0.00)
Posted by Ralph on 2024-01-12, 13:25:12 (75.168.72.225)
The servo protection circuit is overly complex and could be avoided. This circuit was made by Counterpoint and designed by Roger Modjeski (RIP). The servo is intended to allow for no adjustments on th .......
53: High Efficiency Speaker Asylum, crossovers (0.00)
Posted by Ralph on 2024-01-12, 13:11:09 (75.168.72.225)
I find that electronic crossovers often have more coloration than passive ones, assuming both are properly designed. Passive crossovers might seem to rob the speaker of a certain immediacy at lower v .......
54: High Efficiency Speaker Asylum, We tried that tweeter (0.00)
Posted by Ralph on 2024-01-12, 08:54:31 (75.168.72.225)
You can certainly try it, but consider that the main driver isn't being rolled off so it will make energy in the same range as the tweeter. That will cause comb filtering effects, which the ear interp .......
55: High Efficiency Speaker Asylum, Good question! (0.00)
Posted by Ralph on 2024-01-11, 13:31:52 (75.168.72.225)
A driver suitable for OB will usually have a tight suspension. I like the looks of the Supravox stuff a lot; the PHY is nice though- we've had the 12", 8" and 6" units. I like the 6" because it makes .......
56: Amp/Preamp Asylum, 5 year project (0.00)
Posted by Ralph on 2024-01-11, 12:40:05 (75.168.72.225)
I heard an amp at AXPONA 7 1/2 years ago that convinced me class D was something we had to deal with one way or another. So we embarked on the class D project, which took about 5 years before we had .......
57: High Efficiency Speaker Asylum, They all look nice but (0.00)
Posted by Ralph on 2024-01-11, 10:13:31 (75.168.72.225)
no 'full range driver' is actually full range. For best results you'll want a woofer so as to minimize Doppler effect distortion on the main driver, and a tweeter to minimize beaminess and the need f .......
58: Amp/Preamp Asylum, I think your statement is false if I interpreted it correctly; (0.00)
Posted by Ralph on 2024-01-11, 09:35:48 (75.168.72.225)
but if its regarding our class D, that amp does not use a TI chip but instead is a module of our own design. The modules cost considerably more than $50.00 too! For one thing we actually use a heatsin .......
59: Tube DIY Asylum, I suspect this is inconclusive/some circuit tweaks you might consider. (0.00)
Posted by Ralph on 2024-01-10, 11:19:10 (75.168.72.225)
I've been building voltage amplifier circuits like this for nearly 40 years. This circuit is sorely in need of a CCS in the cathode circuit of the bottom tube. You can't apply feedback properly to t .......
60: Tube DIY Asylum, some nice tweaks (0.00)
Posted by Ralph on 2024-01-09, 13:16:56 (75.168.72.225)
If you are willing to do a bit more work you could get more performance out of that. The output section is differential. If the voltage amplifier were differential as well, the distortion profile wou .......
61: OTL Asylum, RE: OTL vs. Class D? (0.00)
Posted by Ralph on 2024-01-09, 11:59:08 (75.168.72.225)
The high impedance of some ESLs challenge most solid state amps to make power since their output power usually is cut in half as impedance is doubled. The class D drives some ESLs, like the Quad ESL5 .......
62: SET Asylum, Nice OPT (0.00)
Posted by Ralph on 2024-01-04, 12:14:56 (75.168.72.225)
I have several 300bs (graphite plate) and a matched pair of new UX250s laying around. I've been thinking I should press them into service. The problem is knowing a good OPT to get. I don't expect it .......
63: Speaker Asylum, You were asking about a tube amp, so tube power in this case :) nt (0.00)
Posted by Ralph on 2024-01-03, 10:10:50 (75.168.72.225)
- .......
64: OTL Asylum, RE: OTL vs. Class D? Not as simple as that! (0.00)
Posted by Ralph on 2024-01-03, 09:53:46 (75.168.72.225)
Let's be clear about something: there are many ways to make amps that run class A, AB or class D. As a result you can't make generalities. There are also a good number of ways to make an OTL, and OTLs .......
65: Speaker Asylum, 60 Watts should do nicely in most rooms. nt (0.00)
Posted by Ralph on 2024-01-02, 13:26:56 (75.168.72.225)
- .......
66: Tube DIY Asylum, If you change the rectifier (0.00)
Posted by Ralph on 2023-12-29, 08:26:18 (75.168.72.225)
You will have too much B+ on the output section. So you will have to compensate somehow, so the operating point of the output tubes remains the same so as to not stress the output transformers. ::: T .......
67: Tube DIY Asylum, This is a lovely amp to update (0.00)
Posted by Ralph on 2023-12-28, 10:03:37 (75.168.72.225)
but the mods you suggest would make any engineer or technician quake in their boots. The last thing you want to find out is that a rare and extremely high quality output transformer has been permanen .......
68: Amp/Preamp Asylum, Yes- but you know that already by now. (0.00)
Posted by Ralph on 2023-12-28, 09:59:37 (75.168.72.225)
The TI chips, if the supporting circuitry around this is done right, are very good. Of course they have a lot of distortion at full power, but if you treat them as a lower powered amp (50Watts or so) .......
69: OTL Asylum, The MP-1 and MP-3 servo system (0.00)
Posted by Ralph on 2023-12-22, 10:49:36 (75.168.72.225)
The LED begins to light up at about 13mV. In normal operation the DC Offset tends to be about 1mV or less. Its rare to have an IC failure to cause the servo to malfunction. If the preamp does not have .......
70: Cable Asylum, find out if your gear supports the balanced line standard (most doesn't) (0.00)
Posted by Ralph on 2023-12-21, 09:56:16 (75.168.72.225)
- in high end audio. If the standard (also known as AES48) is supported, you'll find that the cost or type of balanced cable won't make any difference to its sound, and all of them will sound better t .......
71: OTL Asylum, If you don't have a variac (0.00)
Posted by Ralph on 2023-12-21, 09:48:28 (75.168.72.225)
You can use an incandescent light bulb in series with the AC line. You remove all the tubes, put the lamp in series and turn the amp on. The lamp should light up but go out as the caps charge up. If t .......
72: Tube DIY Asylum, I'm pretty sure that's not the whole picture. (0.00)
Posted by Ralph on 2023-12-20, 09:21:04 (75.168.81.229)
Pay attention in your measurements to what has happened to the 2nd and 5th harmonics. The ear treats the 2nd and 3rd much the same way in that they are innocuous. The 5th isn't innocuous, like all th .......
73: OTL Asylum, Sockets don't cause microphonics. (0.00)
Posted by Ralph on 2023-12-18, 10:32:02 (75.168.81.229)
Microphonic tubes do. Damping rings do very little to address this issue too. So the best place for such a tube is in an amplifier where there is less gain downstream. .......
74: Speaker Asylum, There is nothing that has a chance. (0.00)
Posted by Ralph on 2023-12-14, 11:26:58 (75.168.81.229)
Your 63s will mop the floor with any single driver cone speaker although the latter are usually easier to drive. At lower volume levels this may not seem the case. But as you crank it up, Doppler Eff .......
75: OTL Asylum, RE: How to set the bias with a DMM (0.00)
Posted by Ralph on 2023-12-14, 11:15:45 (75.168.81.229)
All MK3s have automatic bias so this is an older amp. A DC Offset is generated when you depress the Bias Test switch. That switch disconnects one of the two power supplies in the Circlotron output sec .......
76: Amp/Preamp Asylum, RE: (0.00)
Posted by Ralph on 2023-12-07, 11:15:53 (75.168.81.229)
1) A lack of phase shift at 20Hz. So the amp either needs bandwidth to 2Hz so as to minimize 20Hz phase shift or employ enough feedback that its able to correct phase shift at this frequency. 2) A l .......
77: Tube DIY Asylum, correct :) nt (0.00)
Posted by Ralph on 2023-11-28, 11:11:24 (75.168.81.229)
- .......
78: Tube DIY Asylum, RE: +1 nt (0.00)
Posted by Ralph on 2023-11-28, 11:10:47 (75.168.81.229)
- .......
79: Tube DIY Asylum, RE: It won't. (0.00)
Posted by Ralph on 2023-11-27, 13:03:15 (75.168.81.229)
It will increase the differential effect of the output section, resulting in even ordered cancellation, not odd ordered. The entire circuit is thus differential, so even orders are cancelled with eac .......
80: Tube DIY Asylum, You don't need to do a circuit change to direct couple (0.00)
Posted by Ralph on 2023-11-24, 10:25:01 (75.168.81.229)
-assuming the direct coupling is between the input and output tube. In the schematic, the DC voltage on either side of the coupling cap is only 1 Volt. That won't amount to a hill of beans; the coupl .......
81: OTL Asylum, RE: feedback suggestion (0.00)
Posted by Ralph on 2023-11-22, 09:59:26 (75.168.81.229)
If you invert the phase to the output section from the driver, you could send the feedback to the grid of the input tube, mixing it with the incoming audio using a divider network. The advantage of t .......
82: OTL Asylum, RE: M-60's with DeVore Speakers (0.00)
Posted by Ralph on 2023-11-21, 12:25:41 (75.168.81.229)
Not sure if this helps but see the link. .......
83: OTL Asylum, Yes- part of the reason no speaker cable will be perfect... nt (0.00)
Posted by Ralph on 2023-11-18, 11:46:38 (75.168.81.229)
- .......
84: OTL Asylum, 'Dead' is usually easier to fix. (0.00)
Posted by Ralph on 2023-11-13, 08:50:18 (75.168.81.229)
Any competent technician should be able to sort this out. A dead amp usually has a power supply problem; the most common of course being a blown fuse. After than the second most common problem is sho .......
85: Amp/Preamp Asylum, RE: RCA console amp? (0.00)
Posted by Ralph on 2023-11-11, 14:23:21 (75.168.81.229)
I've worked on amps with that topology. But not that one in particular. The AR amp was that topology, Sunn used to make a guitar amp like that and Realistic made a number of amps like that in the late .......
86: Amp/Preamp Asylum, RE: RCA console amp? (0.00)
Posted by Ralph on 2023-11-09, 11:20:52 (75.168.81.229)
Those engineers didn't have much to work with back when this was made. This amp is typical of a lot of solid state amps made in the 1960s- I'd not be surprised if the semiconductors are germanium, but .......
87: Cable Asylum, No. The shield capacitance will influence that of the two conductors, (0.00)
Posted by Ralph on 2023-10-23, 13:28:26 (75.168.134.127)
-As I already mentioned. But you can measure it if you want :) .......
88: Cable Asylum, Mogami already did that for you (0.00)
Posted by Ralph on 2023-10-23, 13:18:51 (75.168.134.127)
But the way to do it is from one conductor to the other; that will take in the capacitance to the shield as well, and will be part of the loading on the cartridge. It is that load and the resulting e .......
89: Cable Asylum, Mogami 2944 is also a good choice. (0.00)
Posted by Ralph on 2023-10-23, 12:56:38 (75.168.134.127)
Capacitance is 22pf/foot, so 1 meter length works good. Your tonearm has the cartridge signal traveling within; the Mogami uses a twisted pair within a shield. The shield is your ground connection and .......
90: Speaker Asylum, How about a set of Fritz Carbon 7s? (0.00)
Posted by Ralph on 2023-10-23, 12:48:34 (75.168.134.127)
I run a pair of his Carbon 6s in my bedroom system and find them very satisfying. We had the Carbon 7s at the shop and liked them a lot. Also reasonably priced. .......
91: OTL Asylum, RE: No. It should be the same nt (0.00)
Posted by Ralph on 2023-10-04, 11:14:55 (75.168.134.127)
. .......
92: Amp/Preamp Asylum, RE: unless you have it refurbished (0.00)
Posted by Ralph on 2023-10-04, 09:43:51 (75.168.134.127)
I'd say 'no'. Its old enough that the power supplies will have to have all the filter caps replaced. Its a tricky preamp to work on; the regulator design is not stable and the board pads fall apart e .......
93: OTL Asylum, RE: Questions about speaker cable characteristic impedance (0.00)
Posted by Ralph on 2023-10-04, 09:40:34 (75.168.134.127)
In a calculation like this the output impedance of the source really isn't relevant- its the impedance of the load. If it does not match the the CI of the cable, energy can be reflected. At audio fre .......
94: SET Asylum, RE: these UL curves, from your link, are the same as the ones I posted. (0.00)
Posted by Ralph on 2023-09-28, 09:57:51 (75.168.134.127)
Yes (I'd have replied sooner but have had my hands full recently). Once you get the plate voltage high enough, the curves look pretty decent. It seems as if you were careful and didn't get greedy, you .......
95: SET Asylum, RE: Ultralinear patent (0.00)
Posted by Ralph on 2023-09-27, 08:23:01 (75.168.134.127)
https://www.oestex.com/tubes/ul.html I thought the link below of special interest as its a single-ended application. .......
96: SET Asylum, RE: Ultralinear patent (0.00)
Posted by Ralph on 2023-09-15, 08:00:47 (75.168.126.122)
To my understanding, yes, a number of manufacturers used slightly different taps with as little as only 2% difference in order to get around the patent. This results in a bowed curve. Of course the t .......
97: SET Asylum, Ultralinear patent (0.00)
Posted by Ralph on 2023-09-14, 14:00:22 (75.168.126.122)
The ultra linear patent, assigned to Arco, disagrees with you. Link below Other manufacturers, like Dynaco and Marantz, recognized the benefit, but not wanting to pay royalties, moved the taps slight .......
98: SET Asylum, You could run that tube in ultralinear mode (0.00)
Posted by Ralph on 2023-09-14, 09:56:29 (75.168.126.122)
If you had the right output transformer... any transformer manufacturer could make one for you. I've done this in some smaller amps and its worked quite well. If the tap is placed properly you get tr .......
99: Tube DIY Asylum, Its a pretty good bet you missed something. (0.00)
Posted by Ralph on 2023-09-13, 13:10:31 (75.168.126.122)
Likely there is a bad connection somewhere. If the amp didn't have this symptom prior to renovation (but otherwise worked the way unrestored amps might...) then its a good bet you introduced a problem .......
100: OTL Asylum, RE: Thank you so much for the clarification, Ralph. V3--)V1 (0.00)
Posted by Ralph on 2023-09-11, 13:52:51 (75.168.126.122)
The S-30 now has a solid state CCS. The middle tube in the rear of the newer M-60s is V2. .......
101: OTL Asylum, RE: What is the function of V3 (CCS tube) in Silver Edition MK3.3 (0.00)
Posted by Ralph on 2023-09-11, 08:55:48 (75.168.126.122)
The CCS is replaced by a solid state circuit in the Mk3.3. This leaves a socket available. We put in parallel with the other two input tubes in the amp, so three 6SN7s are this in parallel at the bott .......
102: General Asylum, OK, now try this on. (0.00)
Posted by Ralph on 2023-09-08, 13:57:44 (75.168.126.122)
To my understanding you don't set up the speakers as you describe. For it to work properly, the subs have to be placed asymmetrically. So its not absorbing the bass at the wall behind the listener. As .......
103: General Asylum, My advice is to read up on it. (0.00)
Posted by Ralph on 2023-09-08, 11:37:16 (75.168.126.122)
Start with Dr. Floyd Toole. .......
104: General Asylum, You can break up standing waves using a DBA (0.00)
Posted by Ralph on 2023-09-07, 15:56:02 (75.168.126.122)
You can't break up standing waves, or more accurately room nodes other than by changing the dimensions of the room. Whatever effect DBAs have they are not "breaking up" room nodes. That's a function .......
105: General Asylum, how DBAs do it (0.00)
Posted by Ralph on 2023-09-07, 12:57:03 (75.168.126.122)
My understanding is that they disperse the energy through placement, level and phase adjustments to smooth out the effects of bass reverb. Is that incorrect? Do they more effectively reduce and elimi .......
106: General Asylum, You probably need to try it (0.00)
Posted by Ralph on 2023-09-07, 12:22:48 (75.168.126.122)
DBAs are very effective. Essentially, your understanding as you stated above is backwards. .......
107: General Asylum, FWIW Dept.: If you want to fix bass in a room (0.00)
Posted by Ralph on 2023-09-07, 08:53:52 (75.168.126.122)
A DBA will do about 95% of what is needed. DSP and bass traps do the remaining 5% in most cases. So you really need a good reason to use DSP since its mostly going to fix things at higher frequencies .......
108: General Asylum, A DBA is easily compatible with the BACCH nt (0.00)
Posted by Ralph on 2023-09-06, 15:00:13 (75.168.126.122)
p .......
109: General Asylum, +1 nt (0.00)
Posted by Ralph on 2023-09-06, 11:50:54 (75.168.126.122)
- .......
110: General Asylum, You can get good bass with a single sub, but (0.00)
Posted by Ralph on 2023-09-06, 08:49:49 (75.168.126.122)
the location of that sub is critical and possibly inconvenient. It does not solve the standing wave problem, it simply makes some of the bass available at the listening position. When you run a DBA .......
111: General Asylum, If you want to fix bass problems, you'll want to start with a DBA (0.00)
Posted by Ralph on 2023-09-06, 08:19:55 (75.168.126.122)
'DBA' means 'Distributed Bass Array' and is used to fix standing waves in the room. Any kind of DSP can't do this. If there is a standing wave, additional power at that frequency is simply cancelled. .......
112: General Asylum, All distortion is more audible that most people think. (0.00)
Posted by Ralph on 2023-08-25, 13:01:41 (75.168.126.122)
The first thing to understand is the ear converts all distortions to tonality. This is the same way that harmonics of real instruments contribute to their tone colors. This should not be controversial .......
113: OTL Asylum, Other than drawing power, I don't think this would win you anything (0.00)
Posted by Ralph on 2023-08-25, 10:23:26 (75.168.126.122)
Once the power tube has had its filament lit up for a minute, there's no benefit to additional warmup insofar as the cathode is concerned. The benefit of putting the amp in Standby for longer periods .......
114: OTL Asylum, RE: The greater amount of power is consumed when the amps are full on (0.00)
Posted by Ralph on 2023-08-18, 10:04:33 (75.168.126.122)
When in Standby you'll find that they really don't run that hot either, even if in Standby all day. OTOH if you start up the amps from stone cold, wait 30 seconds and turn on the B+, you'll find that .......
115: General Asylum, Despite that they do not affect world temperature. (0.00)
Posted by Ralph on 2023-08-16, 09:27:47 (75.168.126.122)
They would if we were bathed in them but we are not. There's simply no correlation. .......
116: General Asylum, Solar flares, sun spots, etc. I should have been more specific but the same holds true nt (0.00)
Posted by Ralph on 2023-08-15, 14:33:20 (75.168.126.122)
- .......
117: General Asylum, Not proof at all- in fact a red herring- sun spots have nothing to do with heat nt (0.00)
Posted by Ralph on 2023-08-15, 11:09:36 (75.168.126.122)
- .......
118: Tubes Asylum, None of these- if you want high performance, start with a triode nt (0.00)
Posted by Ralph on 2023-08-11, 08:57:59 (75.168.94.119)
- .......
119: Tube DIY Asylum, The Ultrapath is a great setup. (0.00)
Posted by Ralph on 2023-08-08, 12:40:48 (75.168.94.119)
Jack knew what he was doing when he designed this circuit (he also holds a patent on class A3 operation for SETs). To improve on it, the way you do it is to use better quality components, do a clean .......
120: Tube DIY Asylum, If you want to regulate, you are better off (0.00)
Posted by Ralph on 2023-08-08, 08:14:29 (75.168.94.119)
regulating the filament voltage. The 6SN7 has a mu of 20 or so; its not going to be particularly sensitive to the B+ voltage and if you did your power supply homework, the B+ will be entirely free of .......
121: Speaker Asylum, If you have the 16 Ohm version (0.00)
Posted by Ralph on 2023-08-03, 08:41:20 (75.168.35.24)
Our S-30 is a great match. One of my employees had the original Rogers speakers and they were quite convincing! We've been making that amp since 1997 so you should be able to find a used one... not su .......
122: Tube DIY Asylum, You have to use a series resistance (0.00)
Posted by Ralph on 2023-08-03, 08:18:22 (75.168.35.24)
So the balance control doesn't load the source. But if you want to talk minimalist, its more so than using dual controls and has the advantage of an easy to find part and no noise whatsoever when its .......
123: Tube DIY Asylum, Why not use a shunt style balance control? (0.00)
Posted by Ralph on 2023-08-02, 11:20:04 (75.168.35.24)
You'd only need a single pot if the circuit is single-ended, and you can use a linear taper. .......
124: SET Asylum, There's one on us audiomart (link) (0.00)
Posted by Ralph on 2023-07-21, 08:19:20 (75.168.35.24)
less risk then giving your credit card to a Chinese website... .......
125: OTL Asylum, RE: It won't hurt to try a 12AT7 (0.00)
Posted by Ralph on 2023-07-21, 08:13:05 (75.168.35.24)
It won't damage the circuit. This amplifier is old enough that its a very good idea to replace the power supply filter capacitors and the output coupling capacitors before running the amp. Otherwise .......
126: OTL Asylum, Thanks. (0.00)
Posted by Ralph on 2023-07-20, 11:22:40 (75.168.35.24)
So it has two power tubes per channel for about 10 Watts into 16 Ohms. Doesn't it then have one 12AX7 and one 12AT7 per channel? That was not obvious in the prior photos. .......
127: OTL Asylum, Could you post a photo of the rear panel? (0.00)
Posted by Ralph on 2023-07-19, 14:33:08 (75.168.35.24)
Its not clear to me if this is a mono or stereo unit. .......
128: OTL Asylum, Based on the information you have (0.00)
Posted by Ralph on 2023-07-19, 14:26:10 (75.168.35.24)
It would appear that the driver tube is the 12AT7 (ECC81) and the input voltage amplifier tubes are the 12AX7s. This amp likely uses negative feedback. So it would need the gain of the 12AX7s to be s .......
129: OTL Asylum, The 6AS7 and 6080 are very similar nt (0.00)
Posted by Ralph on 2023-07-18, 11:23:58 (75.168.35.24)
- .......
130: Amp/Preamp Asylum, Very likely! (0.00)
Posted by Ralph on 2023-07-12, 09:27:50 (75.168.35.24)
A high input impedance at the input of the amp makes it more susceptible to noise. .......
131: Amp/Preamp Asylum, Do yourself a favor- put resistors to ground off of the outputs (0.00)
Posted by Ralph on 2023-07-11, 14:14:44 (75.168.35.24)
1M resistors would do the job. That way you won't need the series resistors which only degrade things by raising the output impedance. If you turn that preamp on and its wired as seen in the schematic .......
132: Speaker Asylum, If you are planning a sub, you might want to plan a tweeter too (0.00)
Posted by Ralph on 2023-06-30, 10:31:28 (75.168.35.24)
and use a crossover to block low frequencies from the wideband driver. Its best to look at any 'full range' driver as a wideband driver; sort of like a midrange unit that has wider range than the typ .......
133: General Asylum, Mate, that's naut a tube. This is a tube (0.00)
Posted by Ralph on 2023-06-29, 13:50:37 (75.168.35.24)
type 212E .......
134: General Asylum, I have read that the step up should be able to deliver 2X the wattage (0.00)
Posted by Ralph on 2023-06-01, 10:09:49 (75.168.128.82)
If you want to prevent the transformer from making its own distortion then this is a good general rule of thumb. .......
135: Amp/Preamp Asylum, +1 nt (0.00)
Posted by Ralph on 2023-05-17, 09:08:38 (75.168.128.82)
- .......
136: Amp/Preamp Asylum, Yes- you are correct. The outboard autoformer you mentioned is called the ZERO (0.00)
Posted by Ralph on 2023-05-16, 12:04:06 (75.168.128.82)
The outboard autoformer you mentioned is called the ZERO. .......
137: Amp/Preamp Asylum, FWIW, its not just the 2nd harmonic (0.00)
Posted by Ralph on 2023-05-15, 11:03:31 (75.168.128.82)
Its more accurate to say 'the lower ordered harmonics' in particular the 2nd and 3rd. If the tube circuit is fully balanced and differential the primary distortion component will be the 3rd rather th .......
138: Amp/Preamp Asylum, The reason is (0.00)
Posted by Ralph on 2023-05-15, 09:37:24 (75.168.128.82)
that even though a solid state amp might double its power going from 8 Ohms to 4, that's not saying the same as the amp is sounding its best. You can clearly see the 4 Ohm distortion is always higher .......
139: OTL Asylum, You'd really have to build and measure it (0.00)
Posted by Ralph on 2023-05-12, 13:56:11 (75.168.128.82)
but I suspect that the ZOBEL network won't be needed in the context of a crossover. A lot will depend on the impedance curves of the drivers in question. If the amplifier has no feedback, even with a .......
140: OTL Asylum, This really sounds like a crossover issue; here's something to consider (0.00)
Posted by Ralph on 2023-05-12, 10:47:27 (75.168.128.82)
If you don't crossover the woofer its impedance will be in parallel with that of the midrange 'full range' driver. OTLs generally don't like lower impedances. If you have 8 Ohm drivers, the speaker w .......
141: SET Asylum, You've got some good suggestions- here's another (0.00)
Posted by Ralph on 2023-05-12, 10:40:55 (75.168.128.82)
If the attenuators of the amp make no difference, the problem is downstream of them. Try removing the input tube and let the amp sit there. If its properly designed this will be no problem. Obviously .......
142: Amp/Preamp Asylum, Obviously false statement! (0.00)
Posted by Ralph on 2023-05-12, 10:34:42 (75.168.128.82)
If it were true, all anyone would need to do is put an output transformer on any solid state amplifier and presto! the classic tube sound. Obviously it doesn't work that way. I've been manufacturing o .......
143: Amp/Preamp Asylum, In the last 60 years?? (0.00)
Posted by Ralph on 2023-05-12, 10:30:41 (75.168.128.82)
I've over the last 60 years of doing this nonsense Discovered that 'competent' SS designs .. frontloaded.. with quality transformers, generate a Tube sound comparable to the best of Tube amps, withou .......
144: OTL Asylum, That's correct. (0.00)
Posted by Ralph on 2023-05-12, 09:03:52 (75.168.128.82)
We've been making them for decades now. .......
145: OTL Asylum, You may not have an output coupling cap- many OTLs don't. (0.00)
Posted by Ralph on 2023-05-11, 10:27:02 (75.168.128.82)
Which includes ours, which also do not have a ZOBEL network at their output. Usually that network is there to stabilize an amplifier at high frequencies- in particular, ultrasonic. You're more likely .......
146: General Asylum, Part of that was Panasonic pulled out of the summer show. (0.00)
Posted by Ralph on 2023-04-24, 12:54:27 (75.168.133.1)
They were a pretty big client, with multiple booths and floor space. IIRC they were spending 6 figures on their display, and decided to limit it to the winter show. .......
147: Tube DIY Asylum, Interesting! (0.00)
Posted by Ralph on 2023-04-24, 10:09:57 (75.168.133.1)
The original UL patent had the tube doing lower distortion right down to nothing at all; linearity did not take a back seat to a triode. Right away other manufacturers such as Dynaco and Marantz got a .......
148: Tube DIY Asylum, No- relevant to an entire market. (0.00)
Posted by Ralph on 2023-04-21, 08:34:46 (75.168.133.1)
I do this for a living and have for 50 years. Once you understand how the human ear's perceptual rules interact with distortion then that allows access to making better sounding amps. The better soun .......
149: Tube DIY Asylum, I've not found that to be the case (0.00)
Posted by Ralph on 2023-04-21, 08:29:53 (75.168.133.1)
when you eliminate the apples and oranges problem. There are three distinct issues: 1) When the SET is compared to a PP amp, its never a PP amp of the same power. As you probably know, the lower power .......
150: Tube DIY Asylum, 6SN7s were developed about 1939... nt (0.00)
Posted by Ralph on 2023-04-20, 14:13:03 (75.168.133.1)
- .......
151: Tube DIY Asylum, Very relevent (0.00)
Posted by Ralph on 2023-04-20, 09:06:02 (75.168.133.1)
If you cause your hand to move, that test will show you that the ear uses higher ordered harmonics to sense sound pressure. If you know that, and you also know the range of hearing, then you know how .......
152: Tube DIY Asylum, If we leave it at that (0.00)
Posted by Ralph on 2023-04-19, 09:22:17 (75.168.133.1)
then solid state amps will continue to be bright and harsh. This is all engineering. Your assumption that higher ordered harmonics can't be heard is where you're getting in trouble, and frankly, is ri .......
153: Tube DIY Asylum, Are you missing my point simply to make me wrong?? (0.00)
Posted by Ralph on 2023-04-18, 09:52:25 (75.168.133.1)
I didn't make any of this up. Its easy to demonstrate that the ear uses higher ordered harmonics to sense sound pressure with very simple test equipment. I can provide the test procedure if interested .......
154: Tube DIY Asylum, :) nt (0.00)
Posted by Ralph on 2023-04-18, 09:44:25 (75.168.133.1)
- .......
155: Tube DIY Asylum, Huh?? of course they are, unless your test equipment lacks resolution... (0.00)
Posted by Ralph on 2023-04-17, 10:53:51 (75.168.133.1)
Keep in mind the effect of rising distortion with frequency. You can have THD of 0.03%, which seems pretty good, but at a higher frequency it might be considerably higher than that (12-18dB higher...) .......
156: Tube DIY Asylum, At 1 Watt the distortion is still lower than an SET. (0.00)
Posted by Ralph on 2023-04-17, 10:17:34 (75.168.133.1)
In any SET sans feedback, the distortion falls off on a sort of linear curve as power is reduced. It behaves quite differently if feedback is involved- usually the noise floor of the amplifier is grea .......
157: Tube DIY Asylum, Yes- that's feedback. (0.00)
Posted by Ralph on 2023-04-17, 10:06:29 (75.168.133.1)
Its only being used to reduce gain, since the amp was already quite musical without it. The feedback node was fairly linear so this worked out fairly well. SETs, for example a 2A3 amp, will produce a .......
158: Tube DIY Asylum, :) +1 nt (0.00)
Posted by Ralph on 2023-04-17, 09:54:52 (75.168.133.1)
- .......
159: Tube DIY Asylum, What do you think causes musical instruments to sound different?? (0.00)
Posted by Ralph on 2023-04-17, 09:48:28 (75.168.133.1)
I would like to believe that something as simple as the harmonic signature accounts for differences we hear - which is what Crowhurst suggested - but I'm highly skeptical. I can tell you the differe .......
160: Tube DIY Asylum, RE: Apples and oranges (0.00)
Posted by Ralph on 2023-04-12, 11:01:09 (75.168.133.1)
Comparing watt-for-watt doesn't "even the playing field," any more than if one considers high(er) efficiency speakers. On a Watt by Watt basis, no. But I think we can both agree that the fist Watt is .......
161: Tube DIY Asylum, They don't. The function of the CCS (0.00)
Posted by Ralph on 2023-04-12, 10:34:50 (75.168.133.1)
is to regulate the current through a differential amplifier pair (the 12AT7 in the schematic). The better the current is regulated, the greater the differential effect, which causes increased gain, lo .......
162: Tube DIY Asylum, schematic for simple 5 Watt amplifier (0.00)
Posted by Ralph on 2023-04-11, 09:56:53 (75.168.133.1)
This uses an Edcor output transformer and JJ multisection filter cap from CE Distribution. .......
163: Tube DIY Asylum, I was speaking from the context of making OTLs the last 50 years (0.00)
Posted by Ralph on 2023-04-11, 08:46:34 (75.168.133.1)
So I'm careful to comment when talking about an amplifier that actually has an output transformer. A proper driver transformer is a fairly large device if of decent quality. This stereo amplifier can .......
164: Tube DIY Asylum, +1 nt (0.00)
Posted by Ralph on 2023-04-10, 10:39:00 (75.168.133.1)
- .......
165: Tube DIY Asylum, Apples and oranges (0.00)
Posted by Ralph on 2023-04-10, 10:33:35 (75.168.133.1)
I think the problem we have when people talk about how great their SET was over a PP amp is the dramatic differences between the two- for example, the PP amp is usually some multiple of the SET's powe .......
166: Tube DIY Asylum, Are you talking about driver transformer coupling? nt (0.00)
Posted by Ralph on 2023-04-10, 10:23:36 (75.168.133.1)
- .......
167: Tube DIY Asylum, Impossible is a stretch (0.00)
Posted by Ralph on 2023-04-07, 11:37:13 (75.168.133.1)
I was able to do it on my first try designing a transformer coupled PP amplifier. The amp is really simple. It was linear enough that I could have easily run it without any feedback. I put feedback i .......
168: Amp/Preamp Asylum, Don't wrroy about the 9V output! That is there for headroom (0.00)
Posted by Ralph on 2023-04-07, 09:25:16 (75.168.133.1)
so it will be lower distortion at the levels at which you play the amp. Our preamp can make 30V in this regard. Its a way to insure lower distortion and can sound better because there's more authorit .......
169: Tube DIY Asylum, RE: Heyboer and Edcor (0.00)
Posted by Ralph on 2023-04-07, 08:49:22 (75.168.133.1)
You'll have to contact Heyboer about your specific needs. They do a lot of custom work, but I suspect that for your application they already have a design on file. The amp I built with the Edcor part .......
170: Tube DIY Asylum, Heyboer and Edcor both make nice EL84 transformers. (0.00)
Posted by Ralph on 2023-04-06, 11:09:37 (75.168.133.1)
So you don't have to sacrifice old iron. I recently built a small integrated amplifier using a pair of Edcor transformers and pairs of EL95s, which make about 5 Watts in push-pull class A1. The bandw .......
171: SET Asylum, So far that's one of the better SETs we've had at the shop (0.00)
Posted by Ralph on 2023-04-06, 10:52:34 (75.168.133.1)
You'd never know it if might be that way from looking inside. I think neatness inside is a big deal. But its important to sound right too. .......
172: Speaker Asylum, that's a nice sounding speaker if you have the right amp (0.00)
Posted by Ralph on 2023-04-06, 10:49:31 (75.168.133.1)
And they are meant for nearfield listening. Think about a studio mixboard between you and them and you've got the ideal distance. I'm probably preaching to the choir... one of my employees had a set a .......
173: Amp/Preamp Asylum, Don't worry about it!! (0.00)
Posted by Ralph on 2023-04-06, 10:45:30 (75.168.133.1)
The input impedance of most any tube amplifier is going to be over 50KOhms. Any solid state preamp can drive that! .......
174: Tube DIY Asylum, Something to consider (0.00)
Posted by Ralph on 2023-04-04, 10:56:37 (75.168.133.1)
Tube producers like JJ rely on the guitar market for the lion's share of their sales. HiFi is a small portion; its the guitar market that allows them to do smaller runs of tubes like the KT170. This h .......
175: Tube DIY Asylum, Any amp with feedback isn't going to clip softly (0.00)
Posted by Ralph on 2023-04-04, 10:26:38 (75.168.133.1)
And this class D is no exception. The simple thing to do though is make sure either the amp has enough power or the speaker is efficient enough that the isn't clipped. If I'm running a tube amp, even .......
176: Tube DIY Asylum, I am and don't miss the tubes at all- and have really similar sound (0.00)
Posted by Ralph on 2023-04-03, 13:34:52 (75.168.133.1)
The class D amps I'm playing have a distortion signature that you'd think was a tube amp if you didn't know better. But there's a lot less of it. So it has the same 'liquidity' and smoothness in the m .......
177: General Asylum, Nah. (0.00)
Posted by Ralph on 2023-03-30, 08:45:30 (75.168.133.1)
I've been a manufacturer for nearly 50 years and our amps have gotten this sort of comment in reviews. It is misleading and needs to die, since it would be regarded as an amplifier failure if such a .......
178: General Asylum, This is a trope that needs to die! (0.00)
Posted by Ralph on 2023-03-29, 12:46:59 (75.168.133.1)
A straight wire with gain would not be able to act as a voltage source. Most loudspeakers are designed with the understanding that the amplifier will behave as a voltage source. A voltage source can d .......
179: Amp/Preamp Asylum, RE: I'll confess I have no personal interest in phono preamps (0.00)
Posted by Ralph on 2023-03-23, 11:04:20 (75.168.84.60)
But based on measurements at least, some good -- and even cheap -- S/S phono preamps apparently exist, (e.g. link). I certainly have no issue with op amps. I'm not used to seeing overload margins pub .......
180: Speaker Asylum, I do. (0.00)
Posted by Ralph on 2023-03-23, 09:58:50 (75.168.84.60)
Its a bit more sophisticated. .......
181: Amp/Preamp Asylum, Or getting rid of unpleasent distortion and a few other things (0.00)
Posted by Ralph on 2023-03-23, 08:49:54 (75.168.84.60)
The only way I've seen successful solid state preamps executed is if they are opamp based, using modern opamps. They can have enough Gain Bandwidth Product to support the feedback they use, resulting .......
182: Speaker Asylum, Really respectable if the crossover is updated (which is fairly easy) nt (0.00)
Posted by Ralph on 2023-03-22, 11:13:33 (75.168.84.60)
- .......
183: General Asylum, Back when the Apple 2 was King... nt (0.00)
Posted by Ralph on 2023-03-22, 11:10:38 (75.168.84.60)
- .......
184: OTL Asylum, My vote is in the preamp- the further upstream the better nt (0.00)
Posted by Ralph on 2023-03-22, 08:36:36 (75.168.84.60)
- .......
185: OTL Asylum, No- what is important is that the tube actually be good and tests strong nt (0.00)
Posted by Ralph on 2023-03-07, 14:55:13 (75.168.84.60)
- .......
186: OTL Asylum, MP-1 Mk3.3 most important tube positions. (0.00)
Posted by Ralph on 2023-02-22, 13:10:57 (75.168.84.60)
For the 6SN7s, the one in each channel closest to the front has the most effect. The Linlai is the best we've heard so far. No idea how long they last. The best NOS tube seems to the the KenRad. For t .......
187: Tube DIY Asylum, That's correct. (0.00)
Posted by Ralph on 2023-02-15, 13:51:20 (75.168.84.60)
Instead what I said is that mixing via a resistive divider network is more linear than doing inside an active device. In that way I'm able to include transistors, where this problem is even worse. ::: .......
188: Tube DIY Asylum, :) I did, like several times... nt (0.00)
Posted by Ralph on 2023-02-15, 11:31:58 (75.168.84.60)
- .......
189: Tube DIY Asylum, Of course! (0.00)
Posted by Ralph on 2023-02-15, 11:04:35 (75.168.84.60)
If you think about it, the local feedback isn't linear. The feedback signal absolutely must not be distorted before it can do its job! Otherwise distortion will be generated. .......
190: Tube DIY Asylum, Here's a drawing... (0.00)
Posted by Ralph on 2023-02-15, 10:16:01 (75.168.84.60)
As you can see, the linearity of the tube distorts the feedback signal when the mixing occurs. When mixed at the grid this does not happen. Of course the signal becomes distorted in the tube, but t .......
191: Tube DIY Asylum, RE: On point (0.00)
Posted by Ralph on 2023-02-15, 09:15:30 (75.168.84.60)
Because the mixing occurs within the tube's influence, so is distorted. When you mix at the grid this does not occur. .......
192: Tube DIY Asylum, Its a good one, but does not mention (0.00)
Posted by Ralph on 2023-02-14, 13:19:36 (75.168.84.60)
the effects of non-linearity at the feedback node. .......
193: General Asylum, KT120s suck anyway don't they? (0.00)
Posted by Ralph on 2023-02-14, 09:19:21 (75.168.84.60)
As I understand it the KT88 is a better sounding tube with lower distortion. JJ makes a pretty nice one BTW. .......
194: Tube DIY Asylum, On point (0.00)
Posted by Ralph on 2023-02-14, 08:53:52 (75.168.84.60)
I've been on point, but I've noticed that we don't seem to be communicating- I'm thinking I've had pretty succinct explanations... My response had everything to do with your question! To delve deeper, .......
195: Tube DIY Asylum, Local feedback (0.00)
Posted by Ralph on 2023-02-13, 10:36:18 (75.168.84.60)
Why is that different than a feedback series resistor feeding the grid with a grid resistor to ground? Its not that different other than you'd have only one feedback loop for the entire amplifier ci .......
196: Tube DIY Asylum, Of course! (0.00)
Posted by Ralph on 2023-02-10, 14:31:49 (75.168.138.177)
But it will be more accurately modified to correct for the non-linearity. .......
197: Tube DIY Asylum, distorted signal (0.00)
Posted by Ralph on 2023-02-10, 10:32:52 (75.168.138.177)
When feedback is taken from the output, of course the assumption is that the output signal is distorted compared to the original. I think where you might misunderstand what I've been saying here is th .......
198: Tube DIY Asylum, :) +1 nt (0.00)
Posted by Ralph on 2023-02-09, 13:47:13 (75.168.138.177)
- .......
199: OTL Asylum, Dust can be a major factor when dealing with high voltages (0.00)
Posted by Ralph on 2023-02-09, 12:21:45 (75.168.138.177)
So a good cleaning is probably in order. Beyond that, change out all the electrolytic capacitors. Sitting does them no good and neither does age. Looks like quite the project- good luck!! ::: TOPIC: .......
200: OTL Asylum, 120-140Volts should get you in the ballpark. (0.00)
Posted by Ralph on 2023-02-09, 12:17:29 (75.168.138.177)
The maximum voltage allowable is (IIRC) 250V. .......
201: Tube DIY Asylum, In a conventional tradition tube amp this would be easy to do. (0.00)
Posted by Ralph on 2023-02-09, 09:46:10 (75.168.138.177)
If any of those projects involve tube amps, it would only take a few minutes to switch from one technique to the other. .......
202: Tube DIY Asylum, RE: Why would the input tube appear to be more linear (0.00)
Posted by Ralph on 2023-02-09, 09:41:51 (75.168.138.177)
I am confused by "mixed in the tube"? Of course the tube is non-linear, if it were linear then there would be no need for feedback to lower the distortion. A little of the distorted output fed back i .......
203: Tube DIY Asylum, dynamics and aliveness (0.00)
Posted by Ralph on 2023-02-08, 10:56:19 (75.168.138.177)
Over time I've become convinced that when audiophiles use the term 'dynamics' they really mean 'distortion' (and in particular, higher ordered harmonic distortion). Effectively in 95% of audiophile co .......
204: Tube DIY Asylum, You should try it (0.00)
Posted by Ralph on 2023-02-08, 10:11:58 (75.168.138.177)
I don't disagree with that, but it's not clear to me that this statement is sufficient to validate a claim to a significant benefit. We've always done it that way since there is no means of feeding .......
205: Tube DIY Asylum, Norman Crowhurst (0.00)
Posted by Ralph on 2023-02-07, 12:31:41 (75.168.138.177)
wrote about this 60 years ago. You might want to read his comments on this, buried somewhere I can't recall, but probably the tome is on Pete Millet's website, link below. Now Crowhurst did not say th .......
206: Tube DIY Asylum, common misconception (0.00)
Posted by Ralph on 2023-02-07, 12:20:27 (75.168.138.177)
Plate to grid feedback has time delay causing the same negative effect of loop NFB. This statement is incorrect. What there is, is phase shift, which if looked at a particular frequency will look li .......
207: Tube DIY Asylum, Why would the input tube appear to be more linear (0.00)
Posted by Ralph on 2023-02-06, 09:15:51 (75.168.138.177)
Why would the input tube appear to be more linear when the feedback is applied to its grid than when it's applied to the cathode? It won't. But the feedback signal won't be mixed in the tube as per .......
208: Tube DIY Asylum, Feedback is usually misapplied. You might want to try this (0.00)
Posted by Ralph on 2023-02-03, 09:38:07 (75.168.138.177)
Usually feedback in a tube amp is connected to the cathode of the input tube. The tube isn't linear although it might be 'fairly linear'. As a result the feedback signal gets distorted before it can d .......
209: Amp/Preamp Asylum, "ignorance is curable, stupid is forever" -Robert Heinlein nt (0.00)
Posted by Ralph on 2023-02-03, 09:27:26 (75.168.138.177)
- .......
210: OTL Asylum, I think this is a power supply problem. (0.00)
Posted by Ralph on 2023-02-01, 09:00:38 (75.168.138.177)
Specifically, a failing filter capacitor. If you cycle the amp off after the warble starts and turn it back on 30 seconds later is the problem still there? It might come back after only a minute, but .......
211: Amp/Preamp Asylum, RE: Thanks, everyone... (0.00)
Posted by Ralph on 2023-01-31, 10:37:16 (75.168.138.177)
I doubt this will be a problem for any speaker since it apparently isn't a high power event. .......
212: Amp/Preamp Asylum, I would think that the gain of the amplifier is more important here (0.00)
Posted by Ralph on 2023-01-31, 10:12:00 (75.168.138.177)
since the noise of what's upstream stands a good chance of being your noise floor. The less gain the amp has, the more you benefit from 'gain riding'. .......
213: Amp/Preamp Asylum, how do you deal with the noise floor of the crossover? nt (0.00)
Posted by Ralph on 2023-01-31, 09:36:34 (75.168.138.177)
- .......
214: OTL Asylum, A possible update (0.00)
Posted by Ralph on 2023-01-27, 14:24:46 (75.168.138.177)
Replace the current limiting resistors in the output section with 5 Ohm devices. You may find that the output power goes up slightly, before saturation, as the current between the power tubes is more .......
215: Amp/Preamp Asylum, Not if its made in the US and built properly. (0.00)
Posted by Ralph on 2023-01-26, 13:04:50 (75.168.138.177)
The chassis is built strong enough to support the power transformer without deformation in shipping. Its all hand-built including the circuit boards using good quality parts instead of the bargain bas .......
216: Amp/Preamp Asylum, This can happen if the B+ of the preamp isn't regulated. (0.00)
Posted by Ralph on 2023-01-26, 09:47:32 (75.168.138.177)
When you power up the amp, the line voltage drops a bit and then recovers. This causes the B+ of the preamp to drop a bit and then recover too. Its a pretty long time constant, so you just see the woo .......
217: Amp/Preamp Asylum, +1 nt (0.00)
Posted by Ralph on 2023-01-26, 09:44:16 (75.168.138.177)
- .......
218: Amp/Preamp Asylum, Proper procedure for powering up any stereo with seperate components (0.00)
Posted by Ralph on 2023-01-26, 08:45:44 (75.168.138.177)
This is normal for most preamps ever made. To prevent it: 1) power up preamp and wait until it settles. 2) insure the volume is down. 3) power up whatever sources you're using 4) power up the power am .......
219: Amp/Preamp Asylum, RE: Bought a pair of Atma-Sphere Class D poweramps (0.00)
Posted by Ralph on 2023-01-26, 08:23:39 (75.168.138.177)
Those amps were four grand!!!!!!!!!!!! Unless I'm mistaking the meaning of this sentence, this statement is false. .......
220: Tweakers' Asylum, You're right; my apologies nt (0.00)
Posted by Ralph on 2023-01-23, 10:22:08 (75.168.138.177)
- .......
221: Tweakers' Asylum, RE: +1 If a fuse was really 'directional' it would heat up and fail in an AC circuit :) nt (0.00)
Posted by Ralph on 2023-01-20, 13:20:17 (75.168.138.177)
- .......
222: Tweakers' Asylum, RE: Voltage drop, but there's something you're not getting (0.00)
Posted by Ralph on 2023-01-20, 11:42:55 (75.168.138.177)
Is that a lot also depends on in what the fuse is being used. In the case I measured, the amp was a zero feedback tube amp with a rather large filament circuit (about 19 Amps). Because there's no cor .......
223: Amp/Preamp Asylum, Not to my knowledge, but that would not be the first time I've been wrong nt (0.00)
Posted by Ralph on 2023-01-05, 10:15:50 (75.168.138.177)
- .......
224: Amp/Preamp Asylum, RE: After all this bul...er...dialogue, does anyone here have a pair? (0.00)
Posted by Ralph on 2022-12-29, 13:48:52 (75.168.151.243)
Here's the interior: The 1/4" side panels are removed in this shot. Toroid on the left. DC blocker to prevent transformer noise/saturation at top. Power supply board with 105 degree caps and over- .......
225: Amp/Preamp Asylum, Please reread what I said. (0.00)
Posted by Ralph on 2022-12-29, 13:31:15 (75.168.151.243)
Do you have a reading comprehension issue? Or is this a way of trying to save face for trying to argue a logical fallacy? .......
226: Amp/Preamp Asylum, Use of logical fallacies results in an inherently false statement. The above is an example (0.00)
Posted by Ralph on 2022-12-29, 12:00:17 (75.168.151.243)
In this case you are knocking down an argument that you made. I never said I didn't have the equipment. I said I have an hp analyzer, which is very different. Its designed really well and built real .......
227: Amp/Preamp Asylum, That's nice (0.00)
Posted by Ralph on 2022-12-29, 11:16:45 (75.168.151.243)
And apparently you believe it. I think you have good reason- Hypex has demonstrated they can be trusted. This is a trust issue after all. Its the internet. You can put up anything you want. I find it .......
228: Amp/Preamp Asylum, here ya go (0.00)
Posted by Ralph on 2022-12-29, 11:00:38 (75.168.151.243)
- .......
229: Amp/Preamp Asylum, What you call 'specs' are what we measured. (0.00)
Posted by Ralph on 2022-12-29, 09:58:44 (75.168.151.243)
They seem common to all the amps. Measurements would be on a specific amp. Since all of them so far have measured the same, that's what's on the website. Perhaps I should change the word 'specs' to m .......
230: Amp/Preamp Asylum, I do. Its what you've been doing. (0.00)
Posted by Ralph on 2022-12-28, 13:02:36 (75.168.151.243)
We've published measurements- they are on our site. You don't like them and are unable to understand what the text (and what I've been telling you) actually means. Read up on it and it will be really .......
231: Amp/Preamp Asylum, elitist snobs come in all kinds of flavors and money has nothing to do with it nt (0.00)
Posted by Ralph on 2022-12-28, 12:26:12 (75.168.151.243)
- .......
232: Amp/Preamp Asylum, These days most guitarist rely on their effects pedals for their 'sound' (0.00)
Posted by Ralph on 2022-12-28, 10:56:35 (75.168.151.243)
And that is a big reason why class D is able to move into the guitar market. As long as you are not relying on how the amp sounds when overdriven into distortion, then a class D is practical. The gui .......
233: Amp/Preamp Asylum, Sheesh (0.00)
Posted by Ralph on 2022-12-28, 10:38:53 (75.168.151.243)
You say you have already said the amp has load invariant frequency response and I should know that from the feedback spec. Yes, I know post filter feedback is a cure but there are several class d amp .......
234: Amp/Preamp Asylum, +1 (0.00)
Posted by Ralph on 2022-12-28, 10:19:07 (75.168.151.243)
Or trolling friend has demonstrated he does not see the difference between taste and perception. Put another way, we all agree that a red light is red and we should stop. He seems to not understand th .......
235: Amp/Preamp Asylum, RE: More trolling or: (0.00)
Posted by Ralph on 2022-12-28, 10:17:03 (75.168.151.243)
I've told you everything you want to know. Now there might be a third explanation, which is that you are not able to interpret the information in a meaningful way. For example you asked about FR with .......
236: Amp/Preamp Asylum, Because I have, and repeated myself several times in doing so yet you persist: (0.00)
Posted by Ralph on 2022-12-28, 09:54:20 (75.168.151.243)
which is a sign I'm being trolled. .......
237: Amp/Preamp Asylum, Or you could read what I already have written, which is the same thing nt (0.00)
Posted by Ralph on 2022-12-28, 09:53:10 (75.168.151.243)
- .......
238: Tube DIY Asylum, FWIW, if the UL is set up right, it looks a lot like that (0.00)
Posted by Ralph on 2022-12-28, 09:31:10 (75.168.151.243)
-that is why I suspect the curves in the OP are of an OPT that has its screen taps misplaced. .......
239: Tube DIY Asylum, +1 nt (0.00)
Posted by Ralph on 2022-12-28, 09:28:30 (75.168.151.243)
- .......
240: Amp/Preamp Asylum, You do and are being willfully ignorant or trolling; which is it? nt (0.00)
Posted by Ralph on 2022-12-28, 09:04:54 (75.168.151.243)
- .......
241: Amp/Preamp Asylum, Sheesh (0.00)
Posted by Ralph on 2022-12-28, 09:04:09 (75.168.151.243)
FR is load invariant. Distortion as with all amplifiers, rises as load impedance is decreased. So if you want the best out of any amplifier the investment dollar is best served by a higher impedance, .......
242: Amp/Preamp Asylum, And one you should be able to draw by now. (0.00)
Posted by Ralph on 2022-12-27, 14:19:07 (75.168.151.243)
What I don't get is if I put up a picture, its still me telling you the same thing. For some reason you seem to not believe me one way but will the other?? That is why I asked if you thought the Hypex .......
243: Amp/Preamp Asylum, RE: I can try... (0.00)
Posted by Ralph on 2022-12-27, 14:14:51 (75.168.151.243)
Finally, when you start asking qualitative/subjective questions of perception, for example: Was the sound scary? Was the sound annoying? Was the sound musical? Was the sound comforting? Which sound s .......
244: Amp/Preamp Asylum, I've certainly talked about it enough! (0.00)
Posted by Ralph on 2022-12-27, 13:00:39 (75.168.151.243)
So you already know that the lower orders are dominant. And you know the amp sounds smooth without harshness so any higher orders are masked. That's a lot of information, given that we already know th .......
245: Amp/Preamp Asylum, Can you clarify? (0.00)
Posted by Ralph on 2022-12-27, 12:56:26 (75.168.151.243)
"Using high harmonics to sense pressure difference"- that's how it works, not well it works for each individual. Surely there is variance from one individual to another in both the qualitative and qu .......
246: Amp/Preamp Asylum, That literally is the only way to do it (0.00)
Posted by Ralph on 2022-12-27, 11:59:40 (75.168.151.243)
They are using a switching power supply; what we found is that if a SMPS is used it must be specifically designed for the class D amplifier application. Otherwise the product will be shot down. ::: TO .......
247: Amp/Preamp Asylum, what is meant by 'inaudible'? (0.00)
Posted by Ralph on 2022-12-27, 11:57:56 (75.168.151.243)
If you mean 'you can't hear it' then yes we can. Again as I've stated previously, the non-linearities in the circuit tend to make lower ordered harmonics, not higher orders. So we're not covering anyt .......
248: Amp/Preamp Asylum, I think the measurements matter a lot (0.00)
Posted by Ralph on 2022-12-27, 11:53:24 (75.168.151.243)
The problem is what measurements. IME if you can't get the distortion below audibility then you have to make sure its inaudible. I know that sounds weird but its true. IME to make the distortion so lo .......
249: Amp/Preamp Asylum, Do you realize you contradicted yourself in this post? (0.00)
Posted by Ralph on 2022-12-27, 11:39:53 (75.168.151.243)
You can't have it both ways. People either have hearing rules or they don't. In the case of higher ordered harmonics the thing you are up against is that the ear uses them to sense sound pressure. Yo .......
250: Amp/Preamp Asylum, Make sure they have a good power supply! (0.00)
Posted by Ralph on 2022-12-27, 11:32:16 (75.168.151.243)
If a class D does not have a robust power supply it will fall flat on its face. I think that is why you read such variable comments on the Purifi and Hypex modules on the web. FWIW good power supply .......
251: Amp/Preamp Asylum, aural camoflage isn't accurate (0.00)
Posted by Ralph on 2022-12-27, 11:24:54 (75.168.151.243)
The assumption being that its there for that purpose. Any designer that ignores how the ear perceives sound and doesn't get distortion below -120dB is going to have variable results if their distortio .......
252: Amp/Preamp Asylum, :) Sinclair's second class d model X-20 was much better. nt (0.00)
Posted by Ralph on 2022-12-27, 11:22:24 (75.168.151.243)
- .......
253: Amp/Preamp Asylum, Thanks (0.00)
Posted by Ralph on 2022-12-27, 10:40:46 (75.168.151.243)
You would not believe the things Bruno had to do to achieve that. You bought one didn't you? .......
254: Amp/Preamp Asylum, I don't discount ASR (0.00)
Posted by Ralph on 2022-12-27, 10:39:19 (75.168.151.243)
entirely. Amirm does very good work; the only issue I see over there is while they are good at the measurements, they seem to know very little about how the ear/brain system perceives sound. So they f .......
255: Amp/Preamp Asylum, RE: Sounding "bright" is a subjective opinion... to an extent. (0.00)
Posted by Ralph on 2022-12-27, 10:21:05 (75.168.151.243)
What you don't seem to get is this: The ear converts all forms of distortion (HD, IMD, aliasing) to a tonality. The ear uses higher ordered harmonics to sense sound pressure so is keenly sensitive to .......
256: Amp/Preamp Asylum, They did! (0.00)
Posted by Ralph on 2022-12-27, 10:12:54 (75.168.151.243)
That is how it was advertised way back then. Apparently the author of that article you linked was misinformed a bit. .......
257: Amp/Preamp Asylum, On that we disagree (0.00)
Posted by Ralph on 2022-12-27, 10:06:26 (75.168.151.243)
claiming "measurements" and "sounds good/bad" are absolutely correlated is a non sequitur. False. Humans may share the same physiology (hardware) but they don't share the same interpretive mechanism .......
258: Amp/Preamp Asylum, :) (0.00)
Posted by Ralph on 2022-12-27, 09:50:55 (75.168.151.243)
I can't speak for the other amps in that list although we've heard good things about them. In our case, the non-linearities in the amp (which are the encoding scheme but mostly the deadtime used in th .......
259: Tube DIY Asylum, Right. As I mentioned previously (0.00)
Posted by Ralph on 2022-12-27, 09:25:39 (75.168.151.243)
Its become commonplace to misplace the taps. The reason for that is the company that got the patent was pretty small and so their version of UL really didn't get out there. I'm sure that had a means o .......
260: Amp/Preamp Asylum, There is a difference between taste and perceptual rules. (0.00)
Posted by Ralph on 2022-12-26, 10:55:44 (75.168.151.243)
Taste is what you like. You might like things really sounding bright. But all who have heard this amp do not say its bright. Whether you like that or not is up to you- that's taste. Do you see the di .......
261: Amp/Preamp Asylum, Just a FWIW: (0.00)
Posted by Ralph on 2022-12-26, 10:51:54 (75.168.151.243)
If we used a Hypex, Purifi or the like, in fact anyone's modules, the price of our amp would be even higher. Like about $1000.00. That is because our chassis is made right here in St. Paul. Its finis .......
262: Amp/Preamp Asylum, It also didn't meet the advertised power of 10 Watts... nt (0.00)
Posted by Ralph on 2022-12-26, 10:38:42 (75.168.151.243)
- .......
263: Amp/Preamp Asylum, That one doesn't seem to be on their website nt (0.00)
Posted by Ralph on 2022-12-26, 10:30:29 (75.168.151.243)
- .......
264: Amp/Preamp Asylum, +1 nt (0.00)
Posted by Ralph on 2022-12-26, 10:23:58 (75.168.151.243)
- .......
265: Amp/Preamp Asylum, There is a correlation if you measure the right things. (0.00)
Posted by Ralph on 2022-12-26, 10:23:10 (75.168.151.243)
There is no functional relationship between opinion and measurements on an individual level which is valid for all individuals. This statement is false. There are human hearing perceptual rules that .......
266: Amp/Preamp Asylum, Good. (0.00)
Posted by Ralph on 2022-12-26, 10:07:19 (75.168.151.243)
If I understand correctly, doesn't Hypex sell their modules without an input buffer? .......
267: Amp/Preamp Asylum, You lost me. (0.00)
Posted by Ralph on 2022-12-26, 09:49:59 (75.168.151.243)
What is meant by your prior post? Are you disputing Mr. Recklinghausen? .......
268: Amp/Preamp Asylum, Do you think its accurate? nt (0.00)
Posted by Ralph on 2022-12-26, 09:48:41 (75.168.151.243)
- .......
269: Tube DIY Asylum, a patentable concept is (0.00)
Posted by Ralph on 2022-12-26, 09:47:27 (75.168.151.243)
anything that you can show has not been done before and isn't considered 'obvious'. This is a very good example and setting the tap to maximized linearity will likely vary from transformer to transfor .......
270: Amp/Preamp Asylum, Of course! (0.00)
Posted by Ralph on 2022-12-26, 09:32:08 (75.168.151.243)
Merrill AGD Atma-Sphere Orchard .......
271: Amp/Preamp Asylum, I think you took something out of context (0.00)
Posted by Ralph on 2022-12-24, 10:57:07 (75.168.151.243)
The old "measures good, sounds bad", "measures bad sounds good" trope is a red herring. This comes from Daniel Recklinghausen, who stated it properly: "If it measures good and sounds bad, it is bad. .......
272: Amp/Preamp Asylum, We're on the same page with a lot of this (0.00)
Posted by Ralph on 2022-12-24, 10:53:30 (75.168.151.243)
If you allow that distortion really does have to be -110 to -120dB then you also realize that none of the amps made today achieve that. So then the distortion spectra of the amplifier becomes importa .......
273: Tube DIY Asylum, Right. (0.00)
Posted by Ralph on 2022-12-24, 10:46:18 (75.168.151.243)
But if you read the patent you will see that the tap is placed to maximize linearity. .......
274: Tube DIY Asylum, ^^ +1 nt (0.00)
Posted by Ralph on 2022-12-23, 13:48:37 (75.168.151.243)
- .......
275: Amp/Preamp Asylum, Now that we got that cleared up (0.00)
Posted by Ralph on 2022-12-23, 13:32:55 (75.168.151.243)
Personally, I prefer amp makes like Hypex, Purifi, Orchard and the like who produce amps with distortion at the threshold or below that of human hearing. I love the idea that distortion can be 'belo .......
276: Tube DIY Asylum, No. UL was patented. So (0.00)
Posted by Ralph on 2022-12-23, 13:05:01 (75.168.151.243)
-to get around the patent, other manufacturers moved the taps around a bit. The curves you're looking at are using one of those 'other' transformers. This is why some people think its great and other .......
277: Amp/Preamp Asylum, Yes, a bit updated though. (0.00)
Posted by Ralph on 2022-12-23, 12:53:35 (75.168.151.243)
Much better opamps, that sort of thing. .......
278: Amp/Preamp Asylum, RE: Perhaps you're not aware- 1960s (0.00)
Posted by Ralph on 2022-12-23, 12:47:03 (75.168.151.243)
Although they were first proposed in the 1960s. The first home use amp was likely the X-10 released by Sinclair Radionics in 1964. .......
279: Amp/Preamp Asylum, Made in USA. Measurements have been published. (0.00)
Posted by Ralph on 2022-12-23, 12:01:29 (75.168.151.243)
Just not as many as you want. There is a difference between that and 'refuses to publish measurements' as you suggest :) The reason this amp is more expensive than most you see is its built to last an .......
280: Amp/Preamp Asylum, we didn't (0.00)
Posted by Ralph on 2022-12-23, 11:42:52 (75.168.151.243)
Hopefully, he will not take the LKV approach of sticking a buffer with a lot of character in front of a transparent Class-D power amp or the AGD approach of implementing a semiconductor manufacturer .......
281: Amp/Preamp Asylum, RE: There are classD amps now that can rival tube amps (0.00)
Posted by Ralph on 2022-12-23, 11:28:36 (75.168.151.243)
-for smoothness and detail- in fact might be just as smooth in the mids and highs. I'm not saying all class D amps do that but some do. At any rate Martin Logans typically need power so I would not p .......
282: OTL Asylum, RE: Variables (0.00)
Posted by Ralph on 2022-12-20, 11:26:45 (75.168.151.243)
Read it somewhere that one could increase phono stage impedance from 47K to 100K or higher to give higher primary load that cartridge sees and increase efficiency (gain). Do I understand correctly? .......
283: OTL Asylum, RE: Variables (0.00)
Posted by Ralph on 2022-12-20, 10:19:08 (75.168.151.243)
That sounds to me that the SUT is designed for your cartridge. Is that correct? If not, then it will take some testing on the bench with your cartridge to sort out what the correct loading should be. .......
284: OTL Asylum, Variables (0.00)
Posted by Ralph on 2022-12-20, 09:38:34 (75.168.151.243)
The phono gain without the cascode is about 45 dB. Works nice with 5mV. Pay attention to loading of the output of the SUT. If its designed for your cartridge the stock load of the preamp (47K) is prob .......
285: General Asylum, There are plenty of recordings that don't employ EQ. (0.00)
Posted by Ralph on 2022-12-19, 14:04:52 (75.168.151.243)
Digital purists that make the best digital recordings will do so using a single pair of microphones or perhaps 3 so as to present a proper stereo sound stage. LPs of course employ pre-emphasis in reco .......
286: OTL Asylum, Does factory have jumper/adapter for purchase? Yes. nt (0.00)
Posted by Ralph on 2022-12-16, 12:43:45 (75.168.151.243)
- .......
287: OTL Asylum, omni directional speakers always measure less than their real efficiency. (0.00)
Posted by Ralph on 2022-12-01, 14:17:32 (75.168.151.243)
This is because the microphone, place at one meter, simply does not pick up all the information leaving the speaker diaphragm. It bounces around in the room though. Speakers like this need to have ro .......
288: General Asylum, RE: She was very nice (0.00)
Posted by Ralph on 2022-11-10, 13:33:49 (75.168.36.171)
My bandmates were eulogizing her last night at rehearsal. The guitar player in my band went to all their 90s shows here in the Twin Cities. We share our space with one of the former bass players in th .......
289: General Asylum, You can make it too simple you know... (0.00)
Posted by Ralph on 2022-11-02, 11:54:30 (75.168.36.171)
For example 'full range' drivers aren't full range. And they don't like it when you play anything complex on them although they might sound amazing on simple material. This is because one driver play .......
290: Tube DIY Asylum, 6SN7s can drive 6AS7s quite well IME. (0.00)
Posted by Ralph on 2022-11-01, 13:01:09 (75.168.36.171)
We've been doing it for decades. In fact one 6SN7 section can drive as many as seven 6AS7s in parallel- with plenty of bandwidth, if as a CF. So used as a CF it could drive both sections of the 6080 i .......
291: Speaker Asylum, Classic Audio Loudspeakers model T3 (0.00)
Posted by Ralph on 2022-10-27, 12:55:38 (75.168.36.171)
It might be T3.3 or T3.4, not sure about that. Made in Brighton, MI. .......
292: Tube DIY Asylum, Regarding 6080s driving headphones (0.00)
Posted by Ralph on 2022-10-27, 12:41:41 (75.168.36.171)
One issue you might run into is the failure of the 6080. One way that can happen is by arcing; if this happens some headphone drivers could be wiped out; at the very least it could be really painful. .......
293: Speaker Asylum, RE: Classic Audio Loudspeakers makes some nice stuff (0.00)
Posted by Ralph on 2022-10-27, 12:38:42 (75.168.36.171)
98dB, 20-25KHz response. No breakups in the midrange field-coil-powered driver so its very smooth. I've had a set of T3s for the last 25 years- updated the crossovers added the second 15" woofer and b .......
294: Vinyl Asylum, RE: Now playing: More from the ECM catalog...Steve Tibbetts? nt (0.00)
Posted by Ralph on 2022-10-19, 10:30:27 (75.168.36.171)
- .......
295: General Asylum, The last time I heard Yes live (0.00)
Posted by Ralph on 2022-10-06, 13:22:49 (75.168.36.171)
was at the State Theater in Minneapolis back the 1990s. It was pretty obvious that Long Distance Runaround was one of their favorites to play at the time. I saw the show with Earl Root (RIP) who was .......
296: General Asylum, You might ask him if it was normalized... nt (0.00)
Posted by Ralph on 2022-09-29, 09:12:23 (75.168.89.49)
- .......
297: Vinyl Asylum, Steve Tibbetts, Safe Journey nt (0.00)
Posted by Ralph on 2022-09-28, 11:05:27 (75.168.89.49)
- .......
298: General Asylum, The clue is in the OP (0.00)
Posted by Ralph on 2022-09-28, 11:03:11 (75.168.89.49)
John mentions the original CD was from 40 years ago. I think normalization was quite rare back then! But today its par for the course. So no weird voltages, just more bits available for resolution. An .......
299: General Asylum, RE: He'll probably appreciate the normalization. That was much harder to do 40 years ago nt (0.00)
Posted by Ralph on 2022-09-28, 09:34:41 (75.168.89.49)
- .......
300: General Asylum, It probably didn't. (0.00)
Posted by Ralph on 2022-09-28, 09:29:03 (75.168.89.49)
I suspect the remastered CD was normalized. .......
301: General Asylum, Sounds like it got normalized based on the description. Apply Occam's Razor (0.00)
Posted by Ralph on 2022-09-28, 09:27:39 (75.168.89.49)
Authorized or no. When your DAC is making 0VU if Redbook the output is 2 Volts. There's not a way to get the DAC to make more than that. But if you normalize the tracks you can take advantage of all t .......
302: Tubes Asylum, Yes. (0.00)
Posted by Ralph on 2022-09-27, 09:35:22 (75.168.89.49)
Thanks again- Very nice tubes. I appreciate the greater longevity of NOS tubes. But audiophiles have been scouring the countryside for decades looking for old shops and the like where they might be s .......
303: Tube DIY Asylum, Yes is the short answer. (0.00)
Posted by Ralph on 2022-09-27, 09:31:27 (75.168.89.49)
If this if for audio its highly recommended! .......
304: Amp/Preamp Asylum, Look up 'Circlotron' and you will see how that works. (0.00)
Posted by Ralph on 2022-09-27, 09:05:03 (75.168.89.49)
There are two floating power supplies opposed by two tube or transistor banks. Current flows in opposite directions through a common load (the loudspeaker). When the circuit is at idle, the currents c .......
305: Tubes Asylum, RE: Again, a good price if they deliver! (0.00)
Posted by Ralph on 2022-09-27, 08:58:45 (75.168.89.49)
You have to have more than just a name. Even Telefunkens go bad; we had a reviewer place used Telefunkens in one of our preamps which was being reviewed. He returned the preamp for repair since one ch .......
306: Amp/Preamp Asylum, Output filter caps (0.00)
Posted by Ralph on 2022-09-26, 13:15:43 (75.168.89.49)
The thing about the output filtering capacitors in both linear and switching supplies is that it's part of the current path for the audio. I've seen that statement before; its not entirely true. The .......
307: Tube DIY Asylum, The wire usually connects to a ribbon of copper (0.00)
Posted by Ralph on 2022-09-23, 10:05:10 (75.168.89.49)
That sits between the input and output windings. It is called an 'electrostatic shield' (ESS) and is used to prevent capacitive coupling between the windings of the transformer. When the shield is tie .......
308: Amp/Preamp Asylum, RE: Every single crappy wall wart -no longer nt (0.00)
Posted by Ralph on 2022-09-22, 13:55:52 (75.168.89.49)
This is how I put it in case you didn't read my post above. if you really want them to work right in an audio application, they work best if custom built for the job. This pretty well rules out junk .......
309: Amp/Preamp Asylum, IME, especially with amplifiers, the SMPS needs to be custom built. (0.00)
Posted by Ralph on 2022-09-22, 13:52:59 (75.168.89.49)
With preamps and the like, probably not, but that isn't a reason to use a cheap SMPS. Like everything else you get what you pay for. If the SMPS generates RFI noise I would avoid it. Stuff like that h .......
310: Vinyl Asylum, That might be if there is a custom phono preamp of some sort. (0.00)
Posted by Ralph on 2022-09-20, 14:43:03 (75.168.89.49)
But if its any sort of normal preamp then the explanation I gave previously applies. If the latter applies then I've no explanation for 1000pf! That makes no sense to me. If you want, take a look at .......
311: Vinyl Asylum, You want to keep the capacitance as low as possible on any low output cartridge. (0.00)
Posted by Ralph on 2022-09-20, 11:21:05 (75.168.89.49)
The capacitance is in parallel with the inductance of the cartridge and so sets up an electrical resonance. You want to keep that resonant frequency as high as possible. LOMC cartridges have a coil th .......
312: Amp/Preamp Asylum, SMPSs aren't inherently bad. (0.00)
Posted by Ralph on 2022-09-20, 11:04:18 (75.168.89.49)
But if you really want them to work right in an audio application, they work best if custom built for the job. Off-the-shelf stuff is likely to current limit or other such nonsense unless its really a .......
313: Tubes Asylum, A good price if it delivers! nt (0.00)
Posted by Ralph on 2022-09-16, 12:27:08 (75.168.138.226)
- .......
314: Tube DIY Asylum, RE: Have you played with the distortion product? (0.00)
Posted by Ralph on 2022-09-07, 10:52:02 (75.168.138.226)
Its possible to tune the circuit to produce either a dominant 2nd or 3rd by adjusting the cathode resistor value. A dominant third is a cubic non-linearity instead of quadratic (the latter as you poi .......
315: Tube DIY Asylum, So how do you know what the distoriton of the voltage amplifier and driver actually is? nt (0.00)
Posted by Ralph on 2022-09-06, 13:35:15 (75.168.138.226)
- .......
316: Tube DIY Asylum, But the distortion of the voltage amp and driver gets amplified, right? nt (0.00)
Posted by Ralph on 2022-09-01, 11:29:07 (75.168.138.226)
- .......
317: Tube DIY Asylum, Output stage distortion always overrides driver characteristics. (0.00)
Posted by Ralph on 2022-08-31, 09:49:29 (75.168.138.226)
How is that possible?? .......
318: Tube DIY Asylum, 2nd harmonic (0.00)
Posted by Ralph on 2022-08-29, 12:00:10 (75.168.138.226)
The 2nd harmonic is dominant, although just barely larger than the 3rd. That's unusual for a push-pull amp in my experience, especially when it has AC balance controls like this one. I would have exp .......
319: Amp/Preamp Asylum, Now we are getting somewhere- you made my point. (0.00)
Posted by Ralph on 2022-08-24, 09:08:52 (75.168.150.10)
But I'm not conflating anything. The rules of human hearing are independent of what people do with what they hear. They develop preferences. Of course not everyone hears the same- some people have deg .......
320: Amp/Preamp Asylum, you are conflating the rules of human hearing with individual perception. (0.00)
Posted by Ralph on 2022-08-23, 13:54:38 (75.168.150.10)
They aren't the same. Otherwise audio as an industry would be impossible! Where you are getting into trouble was the use of the word 'perception' on its own. Another way to put this is the 'rules of h .......
321: Amp/Preamp Asylum, No worries! (0.00)
Posted by Ralph on 2022-08-23, 13:40:52 (75.168.150.10)
Bruno has done impressive work. .......
322: Amp/Preamp Asylum, OK :) nt (0.00)
Posted by Ralph on 2022-08-23, 09:09:29 (75.168.150.10)
- .......
323: Amp/Preamp Asylum, You are confusing 'perception' as a conscious thing (0.00)
Posted by Ralph on 2022-08-23, 08:48:48 (75.168.150.10)
I have been talking about perceptual rules that are shared by all humans. If this were not so, it would be impossible to design audio equipment. Where you are getting into trouble was the use of the .......
324: Amp/Preamp Asylum, RE: I have had 5 class D amps going back twenty years (0.00)
Posted by Ralph on 2022-08-23, 08:42:00 (75.168.150.10)
That is Atma-Sphere, a long-time, high-end tube amp maker, whose recent class D, GaNFET amp was design with euphonic presentation in mind; see the the link below. To be clear, this statement is fals .......
325: Amp/Preamp Asylum, :) pretty funny! It really doesn't work that way (0.00)
Posted by Ralph on 2022-08-19, 13:26:46 (75.168.150.10)
If it did, the audio industry would not be possible. .......
326: Amp/Preamp Asylum, :) pretty funny! It really doesn't work that way (0.00)
Posted by Ralph on 2022-08-19, 13:09:01 (75.168.150.10)
They way you put it, audio as an industry would not be possible. .......
327: Amp/Preamp Asylum, Easy: no-one would be able to agree on how loud instruments could be (0.00)
Posted by Ralph on 2022-08-19, 11:32:51 (75.168.150.10)
Violins play a certain way, basses play in another way. You see this on a VU meter when recording. If people didn't all hear the same way, some would want the violins a lot lot louder. Or a lot quiete .......
328: Amp/Preamp Asylum, It this were really true musical instruments couldn't be made nt (0.00)
Posted by Ralph on 2022-08-19, 10:44:59 (75.168.150.10)
= .......
329: Amp/Preamp Asylum, exactly nt (0.00)
Posted by Ralph on 2022-08-19, 10:24:40 (75.168.150.10)
- .......
330: Amp/Preamp Asylum, RE: Huh? (0.00)
Posted by Ralph on 2022-08-19, 09:39:53 (75.168.150.10)
There is no way to know how someone else perceives sensory stimulus, short a Vulcan mind probe, due to the subjectivity of perception and descriptive language. But you are welcome to support your cla .......
331: Amp/Preamp Asylum, Your point was (0.00)
Posted by Ralph on 2022-08-19, 08:48:35 (75.168.150.10)
and I quote again: I have seen way too many reviews, read too many anecdotal comments on audio forums, have participated in too many joint listening sessions, wherein different people describe the sam .......
332: Amp/Preamp Asylum, Again, a failure to make your point nt (0.00)
Posted by Ralph on 2022-08-18, 11:21:20 (75.168.150.10)
- .......
333: Amp/Preamp Asylum, You're not making your point nt (0.00)
Posted by Ralph on 2022-08-18, 11:20:37 (75.168.150.10)
- .......
334: Amp/Preamp Asylum, RE: Convenient explanation (0.00)
Posted by Ralph on 2022-08-18, 08:48:48 (75.168.150.10)
Sorry, but there were plenty of people who thought its performance was first rate and others who claimed otherwise. You're not proving your point yet. To refute mine, this amp would have to be descr .......
335: Amp/Preamp Asylum, Again, not meeting the criteria you set out previously. (0.00)
Posted by Ralph on 2022-08-18, 08:44:00 (75.168.150.10)
I get that you don't like class D (without having heard all of them). We've (Atma-Sphere) been making triode tube amps for 49 years. We think our class D amp sounds better, but as far as you know tha .......
336: Amp/Preamp Asylum, Again, not meeting the criteria you set out previously. (0.00)
Posted by Ralph on 2022-08-18, 08:40:25 (75.168.150.10)
Everyone on that thread is talking about different amps, not the same amp. .......
337: Amp/Preamp Asylum, The failure in your logic (0.00)
Posted by Ralph on 2022-08-12, 13:46:36 (75.168.150.10)
Is that no-one has heard all class D amps. 'Some people have heard some' is as accurate as you can get on that. Again, you have to winnow it down to a specific amplifier rather than a class of amp in .......
338: Amp/Preamp Asylum, Right- so really not proving your point (0.00)
Posted by Ralph on 2022-08-12, 12:00:56 (75.168.150.10)
Your point was that an amp in particular might sound warm to some while harsh and bright to others. That thread comments about how some class D amps sound different from other class D amps. Not the s .......
339: Amp/Preamp Asylum, I didn't miss that. (0.00)
Posted by Ralph on 2022-08-12, 09:16:38 (75.168.150.10)
Maybe you missed the comments denigrating the upper frequencies of class d amps in general in that thread. Surely you have heard others without such reservations about certain class d amps. Of cours .......
340: Amp/Preamp Asylum, See post at the link (0.00)
Posted by Ralph on 2022-08-11, 10:22:18 (75.168.150.10)
- .......
341: Amp/Preamp Asylum, Read it but it does not seem to be an example. (0.00)
Posted by Ralph on 2022-08-11, 10:21:16 (75.168.150.10)
One thing that's been really common with class D in particular is the really variable results people get even when the amp is using the same module- but different input buffers. My take on that is how .......
342: Amp/Preamp Asylum, RE: the distinction (0.00)
Posted by Ralph on 2022-08-10, 11:31:21 (75.168.150.10)
I have seen way too many reviews, read too many anecdotal comments on audio forums, have participated in too many joint listening sessions, wherein different people describe the same amp in different .......
343: Amp/Preamp Asylum, RE: the distinction (0.00)
Posted by Ralph on 2022-08-10, 09:09:48 (75.168.150.10)
Again, 100 people hear an amp, many say it sounds clinical (perception), many say it sounds warm (perception). How do we measure "warm"? "sterile"? Its highly unlikely that the first statement abov .......
344: Amp/Preamp Asylum, RE: the distinction (0.00)
Posted by Ralph on 2022-08-09, 11:22:28 (75.168.150.10)
Human perception "rules"? There are no rules that apply to everyone when it comes to agreeing on subjective perceptions. The first part of this simply asks about rules and the answer is 'yes'. What .......
345: Amp/Preamp Asylum, RE: Those are the same people who like some distortion (0.00)
Posted by Ralph on 2022-08-09, 11:14:44 (75.168.150.10)
loads of feedback and many fault his amps because they claim to "not like the feedback sound". And its pretty safe to say that those people also don't really know what they are talking about. Admitte .......
346: Amp/Preamp Asylum, RE: "more musical" (0.00)
Posted by Ralph on 2022-08-09, 09:52:35 (75.168.150.10)
I fail to see how you can correlate subjective descriptions (colored, airy, clinical, etc.) with objective performance, given the variance in human perception. That is simply because you are not dist .......
347: Amp/Preamp Asylum, RE: "more musical" (0.00)
Posted by Ralph on 2022-08-08, 09:05:49 (75.168.150.10)
I understand your desire to correlate objective performance with subjective assessments but given the tremendous range of opinions as to what people find "musical", the old adage, "there is no accoun .......
348: Amp/Preamp Asylum, "more musical" (0.00)
Posted by Ralph on 2022-08-03, 08:43:59 (75.168.150.10)
What does "more musical" mean"? How much is "more"? This is a subjective assessment- opinion not fact. There is a direct line between what is possible to measure nowadays and what we hear; what is 'm .......
349: Amp/Preamp Asylum, patents (0.00)
Posted by Ralph on 2022-08-02, 12:45:20 (75.168.150.10)
and don't perform any where near where hypex and purifi operate. -depending on what is meant by 'performance'. At any rate, GaNFET or no, Bruno's patents must be skirted somehow if one is to design .......
350: General Asylum, Actually the lessor (0.00)
Posted by Ralph on 2022-08-01, 09:49:53 (75.168.150.10)
To some extent, yes. But maybe it's our listening priorities that are the bigger difference. Not to 'some extent' but to all. Imagine some parts of the population whose ears used different perceptua .......
351: Amp/Preamp Asylum, performance (0.00)
Posted by Ralph on 2022-08-01, 08:42:19 (75.168.150.10)
The marketing pitch is attractive but the performance isn't any improvement on what Hypex and Purifi offer with standard devices. The performance issue isn't because of anything about GaNFETs and ev .......
352: Amp/Preamp Asylum, RE: You misread. (0.00)
Posted by Ralph on 2022-07-29, 12:43:41 (75.168.150.10)
GaNFETs have been around at least 10 years. I don't know how long GaNFET based amps have been around, but I have to assume not as long :) There are advantages and disadvantages. The advantage is that .......
353: Amp/Preamp Asylum, RE: huh? (0.00)
Posted by Ralph on 2022-07-29, 12:37:15 (75.168.150.10)
The major issue with the class d audio GaN amps is that they have load dependent frequency response This statement is false. Some do, some don't, depending entirely on topology and not the kind of o .......
354: Amp/Preamp Asylum, Ha! the first commercial class D amps were made in the 1960s (0.00)
Posted by Ralph on 2022-07-29, 10:07:10 (75.168.150.10)
-Shortly after they were proposed in the 1950s... .......
355: Amp/Preamp Asylum, Wait - are GaNFETs new? They've been around for well over a decade nt (0.00)
Posted by Ralph on 2022-07-29, 10:02:52 (75.168.150.10)
- .......
356: OTL Asylum, I was curious about that too but apparently it works alright according to Jeffery nt (0.00)
Posted by Ralph on 2022-07-29, 10:01:34 (75.168.150.10)
- .......
357: Vinyl Asylum, Do I misunderstand your post? (0.00)
Posted by Ralph on 2022-07-21, 12:45:31 (75.168.150.10)
My point is that unless that ask for it, its likely the digital master they get will have DSP. The label really won't care one way or the other so you have to ask to get a non-DSP version if you care .......
358: Vinyl Asylum, I run an LP mastering operation for some years. Something to think about (0.00)
Posted by Ralph on 2022-07-21, 11:12:01 (75.168.150.10)
If the mastering engineer has any sense, when mastering from a digital file he'll get the one that has little or no DSP, since most digital masters have compression built in. This is because there is .......
359: General Asylum, Obviously that isn't the last word. (0.00)
Posted by Ralph on 2022-07-20, 10:46:03 (75.168.150.10)
If you want to correlate what you hear vs what is measured, look at distortion vs frequency (if rising with frequency that shows a lack of gain bandwidth product so will likely be bright and possibly .......
360: General Asylum, RE: A Senior Pontificates - What I've Learned in 7 decades of Audio Madness (0.00)
Posted by Ralph on 2022-07-20, 09:03:56 (75.168.150.10)
The result, surprise, surprise, we hear things differently! Listening to music is so subjective anyway, there is no real right or wrong, good or bad, merely personal likes and dislikes. The rules of .......
361: General Asylum, +1 nt (0.00)
Posted by Ralph on 2022-07-11, 12:22:37 (75.168.137.7)
- .......
362: General Asylum, Stability in amplifiers (0.00)
Posted by Ralph on 2022-06-29, 11:09:35 (75.168.137.7)
The issue here is something called phase margin. Its a measure of how much feedback you can apply before the amp is pushed into oscillation. The oscillation is caused because as frequency is increased .......
363: General Asylum, intersting! You are correct (0.00)
Posted by Ralph on 2022-06-28, 11:57:47 (75.168.137.7)
in amps that have feedback, the damping factor vs frequency mimicks the distortion vs frequency. If the distortion rises with frequency its often because the feedback is falling off so you would expec .......
364: Speaker Asylum, RE: Speakers are voltage-driven devices except those that are not (0.00)
Posted by Ralph on 2022-06-28, 11:46:08 (75.168.137.7)
An example is an ESL whose impedance curve is not based on the resonance of a driver in a box. They tend to want constant power more than constant voltage. Other examples include open baffle designs, .......
365: General Asylum, You'd think that somebody somewhere would have studied this academically. (0.00)
Posted by Ralph on 2022-06-27, 13:06:32 (75.168.137.7)
And you are correct. I think the first thing to understand is the significance of harmonics musically. This one threw me for a long time because I was thinking of things in terms of octaves since I've .......
366: General Asylum, RE: 50Hz to me is a red flag (0.00)
Posted by Ralph on 2022-06-27, 10:29:28 (75.168.137.7)
At 50Hz most any amplifier can do well distortion-wise since no amp has troubles with Gain Bandwidth Product at that frequency. That's part of why solid state amps in general have a good reputation fo .......
367: General Asylum, :) nt (0.00)
Posted by Ralph on 2022-06-27, 10:26:12 (75.168.137.7)
- .......
368: Speaker Asylum, RE: my expectation as well (0.00)
Posted by Ralph on 2022-06-27, 09:53:06 (75.168.137.7)
of the two loudspeakers (2 vs. 4 ohms) are identical. All else being equal, there should be a 3 dB difference (shouldn't there)? I would expect the efficiency to be the same, while the sensitivity v .......
369: General Asylum, We have some work from Harman on loudspeaker frequency response.. (0.00)
Posted by Ralph on 2022-06-27, 09:50:22 (75.168.137.7)
but that's about it. This statement is false. We have quite a lot of data going back 80 years on the audibility of distortion. .......
370: General Asylum, Me too- I can't follow you around with microphones :) nt (0.00)
Posted by Ralph on 2022-06-27, 09:48:53 (75.168.137.7)
- .......
371: General Asylum, RE: Volume level low = good. (0.00)
Posted by Ralph on 2022-06-27, 09:48:04 (75.168.137.7)
Radio Shack made a series of amps in the early 1970s that had a pronounced 2nd harmonic at lower power levels. If properly rebuilt and running at a low volume they sound very tube-like. You don't want .......
372: General Asylum, RE: 2nd and 3rd harmonics (0.00)
Posted by Ralph on 2022-06-27, 09:45:08 (75.168.137.7)
I've understood for quite some time that 2nd/3rd harmonics mask harsh higher order harmonics. What is still unclear to me is the extent that, or at what level, 2nd/3rd in themselves affect the tonali .......
373: General Asylum, RE: Yes. (0.00)
Posted by Ralph on 2022-06-27, 09:16:58 (75.168.137.7)
I would start by looking at the distortion spectra of some popular SETs Or perhaps read some of Lynn Olsen's articles on distortion, like this one: http://www.nutshellhifi.com/library/FindingCG.html C .......
374: General Asylum, RE: Look at distortion vs frequency (0.00)
Posted by Ralph on 2022-06-27, 08:46:53 (75.168.137.7)
In the case of the NAD it appears to lack the Gain Bandwidth Product to support its feedback at higher frequencies- and so you see distortion rise as frequency is increased. This is a bit surprising g .......
375: Speaker Asylum, RE: 2 Ohms is next door to criminal. All power amps will make more distortion (0.00)
Posted by Ralph on 2022-06-24, 11:08:58 (75.168.137.7)
driving that load. So you'll not be able to show off what your amp does. Solid state amps in particular will be brighter, harsher and less detailed all on account of the distortion increase. One solu .......
376: Speaker Asylum, sensitivity isn't the same as efficiency (0.00)
Posted by Ralph on 2022-06-24, 11:05:18 (75.168.137.7)
98 dB @2.83 Volts is 4 Watts. Efficiency is 1 Watt one meter. So if you subtract 6dB you have a better picture of the sort of power needed to drive this speaker. .......
377: General Asylum, RE: Actually, it is! (0.00)
Posted by Ralph on 2022-06-24, 09:32:50 (75.168.137.7)
Ask anyone in '76 and they would have said absolutely it would be resolved by 2020... In 1976 this was a real thing because no amp had the Gain Bandwidth Product to really use feedback properly and .......
378: General Asylum, Sorry to hear this. RIP Peter. nt (0.00)
Posted by Ralph on 2022-06-20, 12:50:07 (75.168.137.7)
- .......
379: High Efficiency Speaker Asylum, RE: Its not the driver so much as the suspension, which is the case with any driver. (0.00)
Posted by Ralph on 2022-05-26, 12:57:17 (75.168.112.222)
Its both audible and measurable. Science. .......
380: Tubes Asylum, Yes (0.00)
Posted by Ralph on 2022-05-24, 10:33:40 (75.168.112.222)
Here ya go: .......
381: OTL Asylum, RE: The cartridge isn't going to care about the load. (0.00)
Posted by Ralph on 2022-05-24, 09:03:40 (75.168.112.222)
LOMC cartridge coils are unaffected by loading at audio frequencies. The reason loading is important for so many LOMC phono sections is that they don't handle the RFI generated by the cartridge and to .......
382: Tubes Asylum, DigiKey nt (0.00)
Posted by Ralph on 2022-05-23, 14:10:33 (75.168.112.222)
- .......
383: Tubes Asylum, You can get 2-way LEDs these days that light in both directions. (0.00)
Posted by Ralph on 2022-05-23, 13:48:16 (75.168.112.222)
This helps get rid of high speed flicker caused by 60Hz switching, if that matters... .......
384: OTL Asylum, You can use the JT-347 with the Ruby no worries. (0.00)
Posted by Ralph on 2022-05-23, 13:22:56 (75.168.112.222)
The step-up is 1:8, which would work fine with the MP-3 phono section. .......
385: General Asylum, RIP Vangelis (0.00)
Posted by Ralph on 2022-05-19, 13:48:41 (75.168.112.222)
Sheesh. One of my early loves of electronia. .......
386: Tube DIY Asylum, A farmer brought in an old Realistic STA-220 (0.00)
Posted by Ralph on 2022-05-12, 13:01:15 (75.168.82.143)
Which he used to play music in the barn for his cows. It had a lot of flies in it :) and a dirty tape monitor switch. When he picked it up, he asked the front counter guy 'hey- what's this onoff switc .......
387: Tubes Asylum, Test it as one of those other tubes and see? nt (0.00)
Posted by Ralph on 2022-05-12, 12:57:55 (75.168.82.143)
- .......
388: General Asylum, Kevin Gray is spot on- he has encountered the same thing I did (0.00)
Posted by Ralph on 2022-05-12, 12:55:39 (75.168.82.143)
When we were mastering LPs, we found we had to ask for a master file that lacked all the DSP used for the digital release, with perhaps the sole issue of normalization (which causes all the tracks to .......
389: High Efficiency Speaker Asylum, +1 bad websites are an epidemic all their own these days nt (0.00)
Posted by Ralph on 2022-05-10, 08:48:31 (75.168.82.143)
- .......
390: Speaker Asylum, Being that this is a planar speaker, you'll want to add up to 6dB to that measurement. (0.00)
Posted by Ralph on 2022-05-10, 08:47:03 (75.168.82.143)
That's because at 1 meter, most of the sound leaving the speaker is not picked up by the microphone because its too close. .......
391: General Asylum, Just FWIW this board does have italics :) (0.00)
Posted by Ralph on 2022-04-29, 13:29:32 (75.168.82.143)
Italics Bold Regular .......
392: Planar Speaker Asylum, It must be a browser issue- I tried that almost right away. (0.00)
Posted by Ralph on 2022-04-29, 12:00:49 (75.168.82.143)
I'm using Firefox. .......
393: Planar Speaker Asylum, Weird- I can see your screenshot easily enough but the photo from the prior post won't load. nt (0.00)
Posted by Ralph on 2022-04-29, 09:27:41 (75.168.82.143)
- .......
394: Planar Speaker Asylum, Photo missing nt (0.00)
Posted by Ralph on 2022-04-29, 08:34:34 (75.168.82.143)
- .......
395: Planar Speaker Asylum, RE: The panel is sectioned differently sort of like a mechanical crossover, (0.00)
Posted by Ralph on 2022-04-28, 15:38:00 (75.168.82.143)
but the driver is all just one big full range unit. I don't think Dr. West would have misled me in this regard :) .......
396: Planar Speaker Asylum, Again: the panel itself is a full range driver. And 12KV sounds about right. (0.00)
Posted by Ralph on 2022-04-28, 13:40:14 (75.168.82.143)
Someone offered that 12KV might be required volts to panels but is that for the big bass panel or little treble ones or is that not relevant question? You'll need a high voltage probe to avoid damag .......
397: Planar Speaker Asylum, RE: If you have the original EI core transformer backplate don't mess with it! (0.00)
Posted by Ralph on 2022-04-28, 09:08:10 (75.168.82.143)
That one is done correctly and that speaker is easy to drive. But it can still suffer the Bias control failure; given the age of the speaker its a good bet they are damaged. They are across the AC lin .......
398: Planar Speaker Asylum, RE: soundlab tips (0.00)
Posted by Ralph on 2022-04-27, 11:16:15 (75.168.82.143)
If these are older speakers the bias controls may well be damaged. If they are they will imitate the proper setting fairly well, except that when you turn them down from crackling, they will be on the .......
399: Tube DIY Asylum, Not a fan of cyro personally (0.00)
Posted by Ralph on 2022-04-19, 09:22:40 (75.168.82.143)
IME tubes don't last as long after cyro. .......
400: Tube DIY Asylum, What? No you don't! (0.00)
Posted by Ralph on 2022-04-18, 10:20:27 (75.168.158.142)
If a tube has a problem it won't matter SE or differential, you have a bad tube. Fortunately they are mounted in sockets for easy replacement :) .......
401: Amp/Preamp Asylum, That tuner has a pretty high output impedance (0.00)
Posted by Ralph on 2022-04-15, 13:16:15 (75.168.158.142)
What is the input impedance of the Citation 11? .......
402: Tube DIY Asylum, The trick is (0.00)
Posted by Ralph on 2022-04-15, 13:02:23 (75.168.158.142)
The problem with using balanced with tubes is no two tubes have ever been built that are even remotely alike. That statement is much more true today, where we find that mechanical tube variations are .......
403: Tube DIY Asylum, I did. (0.00)
Posted by Ralph on 2022-04-15, 10:53:25 (75.168.158.142)
Regarding the 'actual' part I refer you to Norman Crowhurst. He wrote about this some 60 years ago. .......
404: Tube DIY Asylum, Sounding real (0.00)
Posted by Ralph on 2022-04-15, 10:37:37 (75.168.158.142)
I've had customers contact me a number of times over the years; something along this line: 'I was playing my stereo the other day when I realized someone was singing along with the music in my room! H .......
405: Vinyl Asylum, Only in the studio (0.00)
Posted by Ralph on 2022-04-15, 10:27:39 (75.168.158.142)
they are handy there as the LP mastering system is a bit noisy. They are also handy because you can hear things you don't always hear the same way with loudspeakers. The only way you can get that sort .......
406: Tube DIY Asylum, Taste vs hearing perceptual rules (0.00)
Posted by Ralph on 2022-04-15, 10:23:58 (75.168.158.142)
If it had been all-balanced, all the way, it would have sounded very much just as good, but would show a different set of sound signatures, which---- would be a matter of listening preferences-- whic .......
407: Vinyl Asylum, OK- that makes good sense. (0.00)
Posted by Ralph on 2022-04-14, 11:47:39 (75.168.158.142)
Never seen it though. I have to assume that the grooves where this happens are really cut too close- no land at all! .......
408: Tube DIY Asylum, Yes. Thanks! (0.00)
Posted by Ralph on 2022-04-14, 11:46:03 (75.168.158.142)
I wanted the amp to be as linear as possible because I didn't expect to use feedback. But the EL95 was so easy to drive I simply had too much gain! Since one grid of the 12AT7 was simply grounded I u .......
409: Tube DIY Asylum, I've been doing that for decades. (0.00)
Posted by Ralph on 2022-04-14, 11:30:07 (75.168.158.142)
So yes, balanced from cartridge to loudspeaker. If an interstage transformer is involved, it can do the conversion from balanced to single-ended and back without concern, except of course it will add .......
410: Tube DIY Asylum, :) (0.00)
Posted by Ralph on 2022-04-14, 10:19:45 (75.168.158.142)
By the way, most "balanced" studio gear only have balanced inputs and outputs. The circuits in between are single ended. So the barn door has already been left open and all the horses are long gone. .......
411: Tube DIY Asylum, ?huh? how is SE not also a processor?? nt (0.00)
Posted by Ralph on 2022-04-13, 14:11:20 (75.168.158.142)
- .......
412: Tube DIY Asylum, I'm not talking about feedback (0.00)
Posted by Ralph on 2022-04-13, 14:09:10 (75.168.158.142)
But since you brought it up, the issue is masking. When feedback is used in insufficient amounts (IOW, when used in any tube amp) it introduces higher ordered harmonics of its own while suppressing th .......
413: Tube DIY Asylum, RE: You might be taking the wrong approach to PP; many do! (0.00)
Posted by Ralph on 2022-04-13, 14:04:51 (75.168.158.142)
But doesn't the single ended amplifier have a single ended input and why wouldn't that cause the same problem? If all single-ended, the primary non-linearity is quadratic, resulting in the 2nd harmo .......
414: Amp/Preamp Asylum, The problem is many manufacturers advertised outrageous 'current' (0.00)
Posted by Ralph on 2022-04-13, 13:22:16 (75.168.158.142)
which had nothing to do with the actual power the amp made. I gave an example earlier. .......
415: Amp/Preamp Asylum, High end audio isn't driven by price, its driven by intention. (0.00)
Posted by Ralph on 2022-04-13, 12:16:06 (75.168.158.142)
Sometimes that's cheap (Radio Shack made some products that were definitely high end) and sometimes its not. Its also important to keep in mind that economy of scale plays an enormous role. ::: TOPIC .......
416: Vinyl Asylum, an alternative possibility (0.00)
Posted by Ralph on 2022-04-13, 12:13:28 (75.168.158.142)
-you don't want to think about, which is that tape was actually used on those direct to disk LPs. That is, FWIW, a simple explanation... We did a direct to disk project but had an overcut making the d .......
417: Tube DIY Asylum, Actually microphones are all balanced sources (0.00)
Posted by Ralph on 2022-04-13, 12:09:22 (75.168.158.142)
unless they are really cheap mics! Almost any decent mixer will have a balanced input, even if internally single-ended. That does not result in the enhanced 5th harmonic FWIW. Phono cartridges are ba .......
418: Vinyl Asylum, That suggests a mastering problem? (0.00)
Posted by Ralph on 2022-04-13, 11:23:29 (75.168.158.142)
Its not caused by a 'deformation' in the lacquer. The only way that could go on would be a groove with almost no land between the next groove, which is a mastering problem. Direct to Disk is always tr .......
419: Amp/Preamp Asylum, No, not all can. (0.00)
Posted by Ralph on 2022-04-13, 11:16:28 (75.168.158.142)
400 Watts into 2 Ohms is about 14 Amps. The output section has to be safe with that, the heatsinks have to be adequate for that, and finally the power supply has to be able to provide the current with .......
420: Tube DIY Asylum, Check with Norman Crowhurst (0.00)
Posted by Ralph on 2022-04-13, 11:12:34 (75.168.158.142)
He pointed out that in a PP amp with a single-ended voltage amplifier, you'll get a bit of extra 5th harmonic. The ear converts all forms of distortion to tonality and the 5th adds a hardness to the s .......
421: Tube DIY Asylum, You might be taking the wrong approach to PP; many do! (0.00)
Posted by Ralph on 2022-04-13, 11:08:52 (75.168.158.142)
If you combine single-ended and PP (differential) circuits in the same amp you'll get a bit of 5th harmonic due to the summing effect of both quadratic and cubic non-linearities in the amp at the same .......
422: Tube DIY Asylum, I do. (0.00)
Posted by Ralph on 2022-04-13, 10:59:52 (75.168.158.142)
I'll have to open up the amp to verify some values. In the meantime, here's a photo. The output transformers are Edcor CXPP10-10K, which are 10 Watt with UL taps and a 10K plate to plate impedance .......
423: Vinyl Asylum, Which recording is that? None of the DD LPs I have do that. (0.00)
Posted by Ralph on 2022-04-13, 10:25:32 (75.168.158.142)
Even when we did direct to disk cuts we never had problems with that. .......
424: Vinyl Asylum, Print through (0.00)
Posted by Ralph on 2022-04-12, 13:35:37 (75.168.158.142)
2. However, closer grooves are more susceptible to print-through where adjacent revolutions can be faintly heard due to deformation of the master lacquer. This statement is incorrect. Print-through .......
425: Vinyl Asylum, Out of phase bass (0.00)
Posted by Ralph on 2022-04-12, 13:23:37 (75.168.158.142)
- Is the reason for issues with bass in the LP. Hill and dale was more for mono. Passive processors can be used to make the bass by mono for a short period (perhaps a few milliseconds) when out of ph .......
426: Tube DIY Asylum, RE: positive feedback nested in negative feedback (0.00)
Posted by Ralph on 2022-04-12, 11:57:52 (75.168.158.142)
I read an article by John Miller Jr. (of Bendix Radio Division) from the March 1950 episode of Electronics magazine, regarding using both types of feedback in an PP design. Essentially the positive fe .......
427: Tube DIY Asylum, RE: PP vs SE - usually comparing apples and oranges. (0.00)
Posted by Ralph on 2022-04-11, 12:52:34 (75.168.158.142)
If you want to compare an SET against a PP amp, shouldn't the PP amp also use the same power triodes and parts quality? Alternatively, should it not be exactly the amp power output? I wanted to get a .......
428: High Efficiency Speaker Asylum, PHY has a 6" driver (0.00)
Posted by Ralph on 2022-04-11, 12:21:23 (75.168.158.142)
that is quite smooth and does high frequencies about as well as most larger drivers with whizzer cones. If installed in a quarter wave rear loaded horn cabinet its a reasonable size. You don't need mu .......
429: Speaker Asylum, Try some Fritz Speakers (0.00)
Posted by Ralph on 2022-04-11, 12:18:38 (75.168.158.142)
His website looks a bit like it was written in Crayolawrite 1.0, but his speakers are quite good and quite affordable. Easier to drive than Totems too, and that means the amp will run with lower disto .......
430: Amp/Preamp Asylum, RE: High Current Amps? (0.00)
Posted by Ralph on 2022-04-11, 12:13:17 (75.168.158.142)
I love how 'high current' means something other than the only thing it can mean, which in this case is an amp can make a certain power into a certain impedance. Current cannot exist without voltage an .......
431: Amp/Preamp Asylum, RE: Power for Pennies.... except when its not (0.00)
Posted by Ralph on 2022-04-11, 12:03:43 (75.168.158.142)
You make a valid point about Class D "power for pennies". While that is generally true along with fantastic bang for the buck and excellent sound, it doesn't explain the mega-buck audiophile Class D .......
432: Tubes Asylum, Impedance peaks shouldn't be a problem. (0.00)
Posted by Ralph on 2022-04-07, 13:25:02 (75.168.142.52)
Your Mac should act like a voltage source driving those peaks, which means it will throttle back its power on the peaks, which often represent resonance. Solid state amps do that too. The real issue .......
433: Amp/Preamp Asylum, I think so (0.00)
Posted by Ralph on 2022-04-07, 11:23:04 (75.168.142.52)
Roger left his company to several people that I know. I sent one of them an email about your amp. .......
434: Amp/Preamp Asylum, Not contesting that the amp works, but go look at their website; you'll see it is indeed a trademark (0.00)
Posted by Ralph on 2022-03-31, 10:02:48 (75.168.142.52)
and not an actual class of operation. Here is the power formula (which is an extraction of Ohm's Law): 1 Watt= 1 Volt times 1 Amp From this you can see that if you have a voltage, you also have an am .......
435: Amp/Preamp Asylum, Back in the old days (0.00)
Posted by Ralph on 2022-03-31, 09:14:08 (75.168.142.52)
opamps didn't have all that much GBP, and so they had a 'sound' if you asked too much gain of them. So certain guitar effect pedals have these earlier opamps, and if you want them to sound right, you .......
436: Amp/Preamp Asylum, ADH isn't a class, like class A or D, its a marketing thing with a trademark (0.00)
Posted by Ralph on 2022-03-31, 09:11:51 (75.168.142.52)
I took a look at the website where they push this idea. There's a lot of misinformation. I'm guessing its written by the marketing department, by someone not having a grasp of the actual engineering. .......
437: Amp/Preamp Asylum, Its not important! (0.00)
Posted by Ralph on 2022-03-30, 10:52:13 (75.168.142.52)
The reason to run class A is to place the output devices in their most linear region, thus reducing distortion. Its not really to eliminate crossover distortion, should the design be Push-pull. The r .......
438: High Efficiency Speaker Asylum, As long as you have a distributed bass array installed first! (0.00)
Posted by Ralph on 2022-03-16, 11:56:02 (75.168.142.52)
No amount of room correction can fix a standing wave cancelling bass at the listening chair. Its a common and frustrating problem. Room correction won't sort it out due to the cancellation. You could .......
439: General Asylum, Try ebay- I got a Tivoli there for $75.00 nt (0.00)
Posted by Ralph on 2022-03-16, 11:51:25 (75.168.142.52)
- .......
440: Amp/Preamp Asylum, RE: Analog meters are slow. (0.00)
Posted by Ralph on 2022-03-10, 09:56:36 (75.168.142.52)
The Mac works fine, it's just those damn clipping lights! They start coming on around 1/2 volume, way too early, and at 3/4 the lights are solid red. Because the meters are slow, Mac added the clipp .......
441: General Asylum, OK. (0.00)
Posted by Ralph on 2022-02-17, 14:18:12 (75.168.94.240)
http://10audio.com/as_mp3/ This was originally a good review. It was changed when we called Jerry on his BS that a kit-built amp that he had reviewed as factory built didn't fare so well; the interior .......
442: General Asylum, I am serious. (0.00)
Posted by Ralph on 2022-02-17, 14:01:38 (75.168.94.240)
I've seen this guy do stuff like this before, and when its happened there's been an agenda. So like I said earlier, if a thing really doesn't measure up, the ethical thing to do is to send it back ou .......
443: General Asylum, RE: An interesting review (... I guess) (0.00)
Posted by Ralph on 2022-02-17, 11:18:09 (75.168.94.240)
10 Audio leads with the usual audiophile meme that measurements aren't everything. Fine but they provide no links to actual measurements, neither for the NAD C298 nor any other Purifi implementation. .......
444: Speaker Asylum, Could be. (0.00)
Posted by Ralph on 2022-02-09, 14:36:16 (75.168.94.240)
I've seen film caps go bad all on their own. Some from the 80s are less likely to go, but if they are film, they are older film caps prior to the industry really sorting that sort of thing out. If the .......
445: Amp/Preamp Asylum, +1 nt (0.00)
Posted by Ralph on 2022-02-09, 14:34:02 (75.168.94.240)
- .......
446: Amp/Preamp Asylum, We're working on it (0.00)
Posted by Ralph on 2022-02-07, 10:26:37 (75.168.94.240)
One of the issues you have with measuring distortion in a class D amp is the residual; what's left over of the switching frequency after the filter. If all goes well, its a small sine wave at the swit .......
447: Amp/Preamp Asylum, This cannot be overstated. (0.00)
Posted by Ralph on 2022-02-04, 12:40:47 (75.168.94.240)
Some of the more important measurements that could identify sonic shortfalls simply are not provided. It is this simple fact that has caused audiophiles to think that we can hear things we can't mea .......
448: Amp/Preamp Asylum, We'll just have to agree that we don't agree (0.00)
Posted by Ralph on 2022-02-03, 09:43:17 (75.168.94.240)
Uncontrolled vibrations cause audible distortions (that are NOT measureable). I hope you appreciate the obvious contradiction here- how can you know that its distortion if its not measurable?? At be .......
449: Amp/Preamp Asylum, To really know what a resistor does (0.00)
Posted by Ralph on 2022-02-02, 14:48:03 (75.168.94.240)
You have to treat the portions of the circuit where such things matter. That is when you have enough variance that you can pick it up in the instruments. For example, changing out the resistors in the .......
450: Amp/Preamp Asylum, Right now- in limited quantities nt (0.00)
Posted by Ralph on 2022-02-02, 13:40:54 (75.168.94.240)
- .......
451: Tube DIY Asylum, Yikes! (0.00)
Posted by Ralph on 2022-02-02, 13:30:47 (75.168.94.240)
Your chassis isn't grounded right then. Here's what to do: 1) insure that the ground connection of the power cord (green or center pin of the IEC connector) is grounded to the chassis. 2) make sure no .......
452: Tubes Asylum, RE: here's a few (0.00)
Posted by Ralph on 2022-02-02, 13:22:34 (75.168.94.240)
Audio Cyclopedia published by Howard Sams the RCA receiving tube manual any 1960s Radio Amateur Handbook Radiotron Designer's Handbook .......
453: Amp/Preamp Asylum, We've not put up a page yet (0.00)
Posted by Ralph on 2022-02-02, 13:19:12 (75.168.94.240)
Its pretty new. It uses GaNFETs and makes 100 Watts into 8 Ohms and 200 into 4. It has balanced and single-ended inputs. The amps are monoblocks 11" by 13" deep and about 3" high. .......
454: Amp/Preamp Asylum, Yes (0.00)
Posted by Ralph on 2022-02-02, 09:14:27 (75.168.94.240)
Distortion is the key. You're looking for three things: 1) when distortion is graphed vs frequency, there will be no rise in distortion at higher frequencies. You rarely see distortion shown this way .......
455: Amp/Preamp Asylum, Sorry... (0.00)
Posted by Ralph on 2022-02-02, 08:50:07 (75.168.94.240)
You cannot measure any difference between brands of resistors, brands of jacks, brands of caps (except dialectic factor and ESR), all wires, footers, damping, brands of solder, shielding for the most .......
456: Tube DIY Asylum, I suspect a bad connection in the amp. (0.00)
Posted by Ralph on 2022-02-01, 14:02:56 (75.168.94.240)
Since its only in one amp we can eliminate the design as an issue, assuming the bad one is built the same as the good one. I would be looking for broken solder joints (your idea of reflowing them is a .......
457: Amp/Preamp Asylum, RE: What's the key to the Gan sound? (0.00)
Posted by Ralph on 2022-02-01, 13:50:32 (75.168.94.240)
I realize it's subjective, but clearly, something very good is going on here. Thoughts? Its the distortion signature. Our class D amp has a distortion signature that is very much like a good tube a .......
458: Tube DIY Asylum, If its in the input circuit (0.00)
Posted by Ralph on 2022-02-01, 13:19:26 (75.168.94.240)
I would look at a couple of issues. Are you running AC filaments? If yes you may not be able to achieve complete silence. But if you are running AC filaments one thing to look at is how the grounding .......
459: Amp/Preamp Asylum, in the period of time that paper was written (0.00)
Posted by Ralph on 2022-02-01, 13:12:37 (75.168.94.240)
MOSFETs have improved their switching time. As far as that goes its 6 of one and half-dozen of the other. The big difference is GaNFETs have lower gate capacitance and so are easier to drive. They als .......
460: Tube DIY Asylum, the 12AT7 will be lower distortion if you put some resistance in series with each cathode. (0.00)
Posted by Ralph on 2022-01-31, 12:36:30 (75.168.94.240)
50 Ohms ought to do nicely. How much power is it making? .......
461: Amp/Preamp Asylum, Usually you can measure it if you think about it (0.00)
Posted by Ralph on 2022-01-31, 12:23:15 (75.168.94.240)
thing you do to an amp (or whatever) changes the sound....and most of these things CANNOT be measured. Most of the time distortion is the issue with various parts. But you have to look at the harmon .......
462: Amp/Preamp Asylum, Also read Norman Crowhurst- he says the same thing (0.00)
Posted by Ralph on 2022-01-31, 09:47:29 (75.168.94.240)
The trick if you want to use feedback is to have enough that you eliminate the higher ordered harmonics that feedback otherwise creates. Possibly the one exception might be if the amp is very linear .......
463: Tube DIY Asylum, +1 (0.00)
Posted by Ralph on 2022-01-28, 09:52:30 (75.168.94.240)
- .......
464: Amp/Preamp Asylum, RE: Please do...Always up for learning. (0.00)
Posted by Ralph on 2022-01-28, 08:29:16 (75.168.94.240)
link below: .......
465: Amp/Preamp Asylum, There are engineers who agree with me too (0.00)
Posted by Ralph on 2022-01-27, 13:24:36 (75.168.94.240)
Regarding the link from EEWeb, a lot has happened in the MOSFET world in the last 8 years- they have improved a lot. Our class D amp is GaNFET, but in the time it took to do the design work, we saw th .......
466: Amp/Preamp Asylum, feedback (0.00)
Posted by Ralph on 2022-01-27, 10:54:28 (75.168.94.240)
Although the distortion figures may be a bit more than amps with high negative feedback, the low feedback design will sound better, especially with GanFETs. A blanket statement like this has little .......
467: Amp/Preamp Asylum, two differences GaNFETs vs MOSFETs (0.00)
Posted by Ralph on 2022-01-27, 10:47:18 (75.168.94.240)
1) the gate capacitance seems to be on average an order of magnitude lower, which is handy for gate drivers. 2) MOSFETs have a body diode effect which the GanFETs don't. This has a lot to do with how .......
468: Tube DIY Asylum, RE: clairty on a couple of issues (0.00)
Posted by Ralph on 2022-01-24, 15:06:30 (75.168.145.67)
So, I agree with you. But we don't need any of that today. Just run a tube where it operates at the right temperature, uses no feedback, and just listen to it. If the power supply, the build and the .......
469: Tube DIY Asylum, clairty on a couple of issues (0.00)
Posted by Ralph on 2022-01-24, 12:31:42 (75.168.145.67)
Most Negative FBK schemes impose a time-delayed signal onto and mixed-in with the input signal that is going thru the amplifier. This statement is false and I know it well since I used to think the s .......
470: OTL Asylum, How readable is your schematic? (0.00)
Posted by Ralph on 2022-01-21, 14:39:26 (75.168.145.67)
If you've got all the voltages its easy enough to calculate the currents. For example, the current of the filament winding can be sorted by looking up the tube types and seeing what they are rated for .......
471: Tube DIY Asylum, RE: The best way to use feedback (0.00)
Posted by Ralph on 2022-01-20, 11:45:27 (75.168.145.67)
Ralph, I have to ask, why use NFB to reduce gain? WHy not just build in less? Sometimes you can't. For example, in the case of the amplifier of this thread, to get the best performance out of a diffe .......
472: Tube DIY Asylum, The best way to use feedback (0.00)
Posted by Ralph on 2022-01-19, 12:50:03 (75.168.145.67)
is to start with an amp that is fairly linear to begin with. What this means in a nutshell is that amp should be good enough that the only reason to use feedback is to reduce gain. Otherwise you'll ge .......
473: OTL Asylum, Its not balanced; you should be OK. nt (0.00)
Posted by Ralph on 2022-01-18, 10:18:58 (75.168.145.67)
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474: Tube DIY Asylum, RE: Looking for simple fully balanced 6BQ5 schematic (0.00)
Posted by Ralph on 2022-01-18, 10:17:55 (75.168.145.67)
I recently built a fully differential amplifier based on the EL95. Both tubes are designed to be easy to drive so a 12AT7 wired as a differential amplifier should drive it nicely. I recommend an OPT w .......
475: OTL Asylum, It should be safe with almost any OTL (0.00)
Posted by Ralph on 2022-01-18, 08:41:37 (75.168.145.67)
With our stuff you likely will run into a buzz problem since the output of our amps is balanced (neither side is at ground). But you won't hurt the amp. I prefer to run a second output from the preamp .......
476: Tube DIY Asylum, RE: To ge the magic from PP (0.00)
Posted by Ralph on 2022-01-14, 14:17:51 (75.168.145.67)
You can find many of his works on Pete Millet's website, linked below. .......
477: Tube DIY Asylum, Uh, Yikes?? (0.00)
Posted by Ralph on 2022-01-11, 13:38:01 (75.168.29.155)
If I got this right, the switch is on the neutral side of the AC power coming in? If the switch were damaged and shorted to chassis, Bad Things could happen and the fuse not blowing might be part of i .......
478: SET Asylum, It won't damage the OPTs, but (0.00)
Posted by Ralph on 2022-01-11, 13:35:18 (75.168.29.155)
you can expect slightly shorter tube life since a greater amount of the power generated by the output section will be dissipated in the output section. This will cause the output tubes to run warmer. .......
479: Tubes Asylum, not only different power output (0.00)
Posted by Ralph on 2022-01-11, 13:32:57 (75.168.29.155)
but a different plate load is required. IIRC a 6V6 likes to see about 9KOhms plate to plate. The EL34 likes to see something lower, more like 4,000 to 5,000 Ohms. .......
480: Amp/Preamp Asylum, I've heard some class D amps (0.00)
Posted by Ralph on 2022-01-11, 13:27:35 (75.168.29.155)
That have a distortion signature that is like that of a tube amp. But perhaps 2 orders of magnitude lower. The distortion signature, as Feanor mentioned on this thread, is the 'sonic signature' of al .......
481: Tube DIY Asylum, Sorry- 'magic'... nt (0.00)
Posted by Ralph on 2022-01-11, 11:27:35 (75.168.29.155)
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482: Tube DIY Asylum, The problem you get with getting the bass right (0.00)
Posted by Ralph on 2022-01-10, 12:03:54 (75.168.29.155)
Is you need bandwidth well below the lowest frequency to be reproduced. If there is no feedback in the amp this will have to be 10th the lowest frequency in order to prevent phase shift, which otherwi .......
483: Tube DIY Asylum, To ge the majic from PP you need to (0.00)
Posted by Ralph on 2022-01-10, 11:57:01 (75.168.29.155)
run it fully differential with no single-ended circuitry in the amp. The problem is that usually PP amps have single-ended input circuits. This causes the amp to emphasize the 5th harmonic (see Norman .......
484: Tube DIY Asylum, IMO 100uf is overkill. (0.00)
Posted by Ralph on 2022-01-10, 11:04:10 (75.168.29.155)
One thing to consider is how low the output transformer can go. With a 2A3 you can go pretty low; a 10Hz cutoff isn't unreasonable. So I would consider cutting off your coupling caps an octave lower, .......
485: Tube DIY Asylum, RE: You'll want to measure the output impedance of the power supply (0.00)
Posted by Ralph on 2022-01-10, 08:44:03 (75.168.29.155)
Ralph, your amps are pretty much class A push pull, and do have a nearly constant load on the power supply. SETs are variable resistors (the triode) across the power supply, and are a constantly va .......
486: Tube DIY Asylum, OK. What plate voltage? nt (0.00)
Posted by Ralph on 2022-01-07, 15:04:36 (75.168.29.155)
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487: Tube DIY Asylum, How much power will this amp make? nt (0.00)
Posted by Ralph on 2022-01-07, 13:57:56 (75.168.29.155)
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488: Tube DIY Asylum, You'll want to measure the output impedance of the power supply (0.00)
Posted by Ralph on 2022-01-07, 12:39:19 (75.168.29.155)
Look for the output impedance to rise at some frequency. The correct film cap will be of such a value that it 'rolls in' at that frequency, thus keeping the output impedance vs frequency of the supply .......
489: Tubes Asylum, ^^This +1! (0.00)
Posted by Ralph on 2022-01-07, 12:12:30 (75.168.29.155)
The tubes themselves work fine. What you hear as 'differences' are due to other things, in particular the output transformers! Its common knowledge (or should be) that the larger you make an output tr .......
490: Speaker Asylum, Based on your description (0.00)
Posted by Ralph on 2022-01-07, 12:01:51 (75.168.29.155)
I suspect there is a short of some kind at the input of the subwoofer that didn't play. When connected to the output of the preamp, this also killed the output on that channel to the main speaker. Th .......
491: Tube DIY Asylum, IHF vs FTC/RMS power vs Peak power (0.00)
Posted by Ralph on 2022-01-06, 11:58:38 (75.168.97.248)
Back in the old days the specs on output power were a bit of the Wild West. I have a little 5 watt/channel amp made by Radio Shack. They sold it as much greater power (Institute of High Fidelity; IHF) .......
492: Tube DIY Asylum, The part about 'only one section being lit' is the bit that threw me :) nt (0.00)
Posted by Ralph on 2022-01-06, 09:04:40 (75.168.97.248)
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493: Tube DIY Asylum, By having all the elements tied together (0.00)
Posted by Ralph on 2022-01-05, 13:50:16 (75.168.97.248)
the tube will make less noise and the section will be nicely preconditioned. But if it were me I wouldn't have done that- by paralleling sections in a tube you have better control of stray capacitance .......
494: Tube DIY Asylum, Both sections would be lit all the time unless they have a 6SN7 of which no-one was previously aware... nt (0.00)
Posted by Ralph on 2022-01-05, 10:21:46 (75.168.97.248)
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495: Tube DIY Asylum, This makes no sense. (0.00)
Posted by Ralph on 2022-01-05, 10:18:37 (75.168.97.248)
Why have the elements tied together to prevent noise when simply using them would have been more effective (less stray capacitance)?? This simply means more tubes are used; I would not be surprised at .......
496: OTL Asylum, RE: Why aren't OTL tube amps more popular? (0.00)
Posted by Ralph on 2022-01-04, 14:36:10 (75.168.97.248)
Didn't the SA4 use a servo mechanism to cancel DC at the output, in lieu of coupling capacitors? And wasn't that the Achilles heel of that design? I heard about that a lot from Albert Porter back in .......
497: General Asylum, Ha! cassettes have been made continuously in the US by ATR Magnetics (0.00)
Posted by Ralph on 2022-01-03, 11:46:26 (75.168.97.248)
-who is the last audio tape manufacturer in the US left standing. .......
498: OTL Asylum, several reasons (0.00)
Posted by Ralph on 2022-01-03, 11:42:23 (75.168.97.248)
The biggest complaint we run into is 'all the tubes'. The second is that a lot of speakers really don't work that well with OTLs. That's true but from a purely subjective point of view my experience w .......
499: Critic's Corner, next. (0.00)
Posted by Ralph on 2021-12-23, 12:40:20 (75.168.97.248)
Most of the big name turntable/analog reviewers/experts are climbing up the age ladder. Well, most of us are. But apparently you know one that isn't? Dead people don't count :) Have a nice holiday!! .......
500: Tubes Asylum, Yikes! nt (0.00)
Posted by Ralph on 2021-12-23, 12:36:53 (75.168.97.248)
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Found total of 500 records, Query: , Author: Ralph in All Forums, Time: 2 sec.