|
Search of All Forums Enter your search criteria. Click here for tips on using our search |
For Sale Ads |
1: Vintage Asylum, Audio Innovations - problem with switches (0.00)
Posted by Michael V on 2023-10-07, 18:36:40 (73.129.156.165)
I recently purchased an old Audio Innovations step up transformer unit, which seems to have an issue with the toggle switches that allow you to use different impedance settings by using the transfo .......
2: Tube DIY Asylum, "Grid leak bias is not very suitable for use with low level (preamplifier) stages owing to hum." (0.00)
Posted by Michael V on 2021-02-22, 06:26:28 (73.134.211.108)
Was surprised at this, as there are plenty of modern examples of phono stages that use grid leak bias for V2. Including Eli's post below. Any idea why grid leak bias would be associated with hum? ::: .......
3: Tube DIY Asylum, RE: Another 5842 question, grid and cathode (0.00)
Posted by Michael V on 2020-11-08, 18:50:18 (73.134.211.108)
I have used the WE 5842 to drive a JJ2A3 and other DHTs (but not a 300B), all with an HLMP LED. As I recall, I used the 1.5v red LED for 15-17ma at 145v, in a later design the green 2.0v LED for 10ma .......
4: High Efficiency Speaker Asylum, RE: WANTED: outdoor sound system (0.00)
Posted by Michael V on 2020-07-10, 17:04:01 (73.134.211.108)
Great, thanks for the suggestion. Will keep an eye out! .......
5: High Efficiency Speaker Asylum, WANTED: outdoor sound system (0.00)
Posted by Michael V on 2020-07-09, 13:14:26 (73.134.211.108)
Hello. Making the best of our lockdown-state, our neighborhood had a socially distant outdoor movie night. My neighbor "borrowed" a projector from work and I pulled together a sound system. It's a .......
6: High Efficiency Speaker Asylum, Perfect, thanks! nt (0.00)
Posted by Michael V on 2020-06-03, 10:07:28 (69.140.169.54)
.......
7: High Efficiency Speaker Asylum, Yuichi Labs website archive? (0.00)
Posted by Michael V on 2020-06-01, 06:18:04 (69.140.169.54)
It looks like the Yuichi Labs website isn't working anymore. Does anybody know how to find an archived version? About two years ago I made the initial cuts for one of his wooden horn designs, and need .......
8: Tweakers' Asylum, Recommendations for receptacles with isolated ground (0.00)
Posted by Michael V on 2019-11-17, 12:53:20 (69.140.169.54)
Here's the situation: In my new audio room, I have two dedicated circuits. All my equipment is fed by a dual duplex (yes, minimalist...) where the duplexes are on different circuits. Since I'm using a .......
9: High Efficiency Speaker Asylum, Closer look at the Emilar (0.00)
Posted by Michael V on 2018-11-11, 08:48:21 (108.18.115.205)
Your example of the Emilar EH-500 plus adaptor raises a point that has puzzled me. For context, I am somewhat familiar with this combo, as I have been experimenting with it for the past few years with .......
10: K&K Audio / Lundahl Transformers, RE: Follow up (0.00)
Posted by Michael V on 2016-04-25, 12:34:10 (108.31.197.51)
Dave/Kevin: I tried the grounding change but it had no impact. To clarify and restate the problem, the issue is static noise that only appears in silent passages like the beginning and end of songs. I .......
11: K&K Audio / Lundahl Transformers, RE: Follow up (0.00)
Posted by Michael V on 2016-04-10, 07:15:40 (108.56.201.129)
Dave, Thanks for your reply. I did not have another external DAC, so I purchased a used Audio Note Kit DAC 3.1. With the same Sonos source, the ANK has zero noise. I do not have another streaming sour .......
12: K&K Audio / Lundahl Transformers, Follow up (0.00)
Posted by Michael V on 2016-03-06, 20:25:44 (108.56.201.129)
Sonos sent out a replacement unit, and the same problem exists. Now I'm confident the issue lies with the RAKK dac after all (even though the problem doesn't exist with other digital sources into the .......
13: K&K Audio / Lundahl Transformers, RAKK - Sonos compatibility (0.00)
Posted by Michael V on 2016-02-18, 03:52:40 (70.192.198.191)
I've been happily running a Mk I RAKK for the past 10 years, until recently with just an Oppo player as transport. The result has been very satisfying for digital. Last summer I decided to get a Sonos .......
14: Tweakers' Asylum, Kaisei is already available! (0.00)
Posted by Michael V on 2016-01-31, 19:08:57 (108.56.201.129)
And has been for about a year, yet for whatever reason there hasn't been any discussion. I guess folks around here are more interested in coupling caps? Anyway, from their website, AN projects a relea .......
15: Tube DIY Asylum, RE: Beware the Parts Connexion discount that wasnt (0.00)
Posted by Michael V on 2015-10-16, 14:39:32 (70.192.209.85)
IMO, their promos can be a little deceptive. The banner says all items in a category are 25% off, which sounds great but for a line below that says something obscure like "no double discounting". Ins .......
16: General Asylum, Emia (0.00)
Posted by Michael V on 2015-08-30, 10:53:05 (70.192.195.99)
I heard and enjoyed each of those rooms. The Emia room stood out for me because the front-end sounded so clean and effortlessly dynamic. I was able to visit each of the three days. Kudos to Ijaz and D .......
17: SET Asylum, Yes (nt) (0.00)
Posted by Michael V on 2014-02-03, 13:31:10 (71.191.138.132)
.......
18: Tube DIY Asylum, RE: JFX Premium Capacitors: Has anyone tried these ? (0.00)
Posted by Michael V on 2014-01-11, 21:38:15 (71.191.138.132)
I've been using two pairs of these, and I'd say they are pretty good. In crossovers I slightly prefer Sonicap Gen I's for high pass series caps, but the JB JFX are very close. Very good for the $$, es .......
19: Tube DIY Asylum, Good story! nt (0.00)
Posted by Michael V on 2014-01-10, 08:08:10 (209.12.102.161)
.......
20: Tube DIY Asylum, RE: runaway el84 and grid stoppers (0.00)
Posted by Michael V on 2014-01-08, 20:27:55 (64.134.155.191)
You didn't state whether you are using negative feedback, but with cathode bias I wouldn't worry about gridstoppers. My 12V6 amp was fine without stoppers, and I slightly preferred the sound without t .......
21: Tube DIY Asylum, "Never run a tube amp without a load" (0.00)
Posted by Michael V on 2014-01-06, 18:33:56 (108.56.185.92)
Certainly true but the OP said he had a 16 ohm resistor across the secondary. I've experienced this same thing, but surely the output transformers are not "screaming in pain" under such circumstances .......
22: Tube DIY Asylum, Which BG series? (0.00)
Posted by Michael V on 2013-12-02, 19:29:45 (64.134.155.191)
IME, different series of black gates can sound quite different. I use FK as cathode bypass caps and feel they are nicely balanced. The same value cap in the STD series in the same circuit sounds dark .......
23: High Efficiency Speaker Asylum, RE: Horns for TD-4001 (0.00)
Posted by Michael V on 2013-11-25, 11:10:32 (50.58.67.3)
Bruce, Thanks for wading in. When I bought my first pair of TD-2001's from a nice guy outside Philadelphia, I had the opportunity to hear one of your (early?) systems that employed the 4001 on a big w .......
24: High Efficiency Speaker Asylum, RE: BRH 90 (0.00)
Posted by Michael V on 2013-11-24, 19:29:33 (71.178.225.194)
Thanks for the suggestion - just what I had in mind. I'll keep a look out for a used pair. .......
25: High Efficiency Speaker Asylum, Gluca post (0.00)
Posted by Michael V on 2013-11-22, 06:35:34 (50.58.67.3)
Hey Doug. Ran across this pic through earlier searches... .......
26: High Efficiency Speaker Asylum, RE: Horns for TD-4001 (0.00)
Posted by Michael V on 2013-11-22, 06:29:48 (50.58.67.3)
Thanks for sharing your experiences. Your system is my kind of overkill! I was planning a similar 600hz crossover point for the 4001, but I definitely want to hear what it can do up to its upper limi .......
27: High Efficiency Speaker Asylum, RE: jbl 2350 or similar (0.00)
Posted by Michael V on 2013-11-21, 07:54:00 (50.58.67.3)
Thank you, I did read about those but was afraid I literally could not fit them in my room. Before the renovation is finished, I am stuck in a 10.5' wide room. I guess for 2" drivers, the only vintage .......
28: High Efficiency Speaker Asylum, Horns for TD-4001 (0.00)
Posted by Michael V on 2013-11-21, 05:42:45 (50.58.67.3)
Hello, I just acquired a pair of TAD 4001 drivers, and am looking for suggestions on horns to get these babies making music. Are there any cheap/available options out there, such as vintage JBL or oth .......
29: High Efficiency Speaker Asylum, Any reports from those who ordered some? nt (0.00)
Posted by Michael V on 2013-10-20, 21:02:36 (74.96.186.185)
Thanks .......
30: General Asylum, Thanks for all the advice (0.00)
Posted by Michael V on 2013-08-07, 09:14:17 (119.57.33.100)
I just knew someone would give me an idea that proves to be a point of contention with the wife (lose the powder room). That is where I am now leaning... .......
31: General Asylum, Help me design my music room! (with floorplan) (0.00)
Posted by Michael V on 2013-08-06, 06:10:45 (119.57.33.100)
All, We're finishing off the attic of our newly purchased house to (in part) have a dedicated music room. After working through all the other must-haves with the architect/contractor, the dimension .......
32: Tube DIY Asylum, RE: Jupiter HT capacitors. how good are they? (0.00)
Posted by Michael V on 2013-07-24, 06:10:51 (74.96.186.185)
I tried a pair of the HT 600V round case capacitors, as they seemed most similar to their original cap (without the melting!). I felt the newer caps are just OK, as they lost a bit of the natural live .......
33: Tube DIY Asylum, RE: Hammond 156c choke for cathode follower? (0.00)
Posted by Michael V on 2013-06-08, 21:42:50 (74.96.186.185)
I have used the 156C as plate load in various circuits - including a 396a driver stage. I kept the current at around 6ma, and it performed fine. Hum pickup surprisingly hasn't been an issue for me eit .......
34: Tube DIY Asylum, Excellent post, thanks Dave! nt (0.00)
Posted by Michael V on 2013-02-10, 15:08:19 (68.34.86.103)
.......
35: Tube DIY Asylum, RE: " Finally, connect a resistance (100 ohms will do fine) between the chassis and the circuit ground. " (0.00)
Posted by Michael V on 2012-12-03, 19:16:38 (68.34.86.103)
What the poster above was describing is not using a 100R resistor from the PT center tap to ground - the only purpose that would serve is wasting power and maybe destroying your resistor! The 100R re .......
36: Tube DIY Asylum, Intact Audio (0.00)
Posted by Michael V on 2012-04-09, 11:10:26 (38.127.149.123)
Just wired up their autoformer volume control (avc) last night, and definitely recommend it! It may be more expensive compared to alternative resistive potentiometers, but you can easily justify the p .......
37: General Asylum, Audio stores in Tampa/St. Pete? (0.00)
Posted by Michael V on 2012-03-02, 07:46:50 (98.98.105.198)
Visiting Tampa for the weekend, and have some time to kill... Any audio stores worth visiting? I did a quick search on the asylum and didn't find anything interesting. Thanks! .......
38: Tube DIY Asylum, Since you are building from scratch... (0.00)
Posted by Michael V on 2011-08-02, 11:55:12 (38.125.35.34)
You could also just use a gas tube that gives 100v. See the datasheet for Western Electric's equivalent for shunt regulator service. I've been using them for years and they work just as well IME. ::: .......
39: SET Asylum, RE: Visit rooms 302 and 308! (0.00)
Posted by Michael V on 2011-06-27, 07:17:02 (38.125.35.34)
The Deja Vu sound is not for everyone, on that I totally agree. Vu would probably be the first to tell you he values musicality over frequency extension - his sound is definitely not for Wilson fans. .......
40: Tube DIY Asylum, RE: 2C22-5687- IT-807 SE amp w/ series battery on input (0.00)
Posted by Michael V on 2011-03-20, 21:10:38 (72.164.177.214)
Are you really running the 5687 at 5 watt dissipation per side? That's above the maximum rating according to my datasheet. I've found that 8-10ma and 150-190v sounds best to my ears. Congrats on getti .......
41: Tube DIY Asylum, Second Hammond (0.00)
Posted by Michael V on 2010-12-10, 13:29:19 (38.125.35.34)
I've used quite a few open frame Hammonds for choke input duty with no problem. I always make sure the unit is rated for 150% of the current draw, and that you have more than enough inductance for sai .......
42: Tube DIY Asylum, RE: Wire 12V6 tube in triode mode (0.00)
Posted by Michael V on 2010-07-30, 08:31:22 (75.103.235.130)
Screen is Pin #4, and the plate is Pin #3. .......
43: High Efficiency Speaker Asylum, RE: May I ask (0.00)
Posted by Michael V on 2010-07-07, 19:05:47 (96.231.89.240)
"You seem to be wanting to place the blame with GPA here, they brought your drivers back to original specs which is what you asked them and paid them to do, and they likely did a good job of it. That .......
44: High Efficiency Speaker Asylum, RE: Yes (0.00)
Posted by Michael V on 2010-07-07, 06:27:46 (75.103.235.130)
Bob, thanks for your reply. Reading that, I am surprised nobody has explained before that GPA's reconing results in (somewhat) different spec'd drivers. That aside, I already parted with the 416's as .......
45: High Efficiency Speaker Asylum, RE: Anybody other than Great Plains Audio for reconing Altecs? (0.00)
Posted by Michael V on 2010-07-06, 06:30:31 (75.103.235.130)
Yes. Somewhere between 100-150 hours, mostly with loud music but also with heavy LF tones to try to loosen things up. It really sounded like a different driver when it came back. .......
46: High Efficiency Speaker Asylum, Yes (0.00)
Posted by Michael V on 2010-07-06, 06:26:21 (75.103.235.130)
As per doodlebug's comment, that's standard procedure. .......
47: High Efficiency Speaker Asylum, Anybody other than Great Plains Audio for reconing Altecs? (0.00)
Posted by Michael V on 2010-07-05, 14:04:35 (96.231.89.240)
Hello, For reconing Altec 416's or 515s, is there anybody other than GPA that you'd recommend? I have used GPA recently to recone a pair of 416a woofers, and although they looked great I wasn't that i .......
48: MagneQuest/Peerless Forum, Ping: mqracing (0.00)
Posted by Michael V on 2010-06-18, 06:22:13 (75.103.235.130)
Mike - sent you an email last week about the nickel trannies. Could you please respond? Thanks .......
49: Tube DIY Asylum, RE: Emotive Prima Schematic (0.00)
Posted by Michael V on 2010-06-14, 14:04:43 (71.178.139.14)
Wasn't the fixed output just taking the signal off the volume control? That would make sense for use with a subwoofer or bi-amping. I've never seen a Prima, but there ought to be Emotive users out the .......
50: General Asylum, Seconded!!!! (0.00)
Posted by Michael V on 2010-06-01, 09:44:56 (75.103.235.130)
What a waste. .......
51: Tube DIY Asylum, RE: Chassis size (0.00)
Posted by Michael V on 2010-05-11, 06:18:23 (75.103.235.130)
For amplifiers, something like 17"L x 10"W x 3"H is typical. I work hard to avoid oversizing, which can lead to long wire runs (noise pickup) and superfluous solder joints (sonic degradation). That's .......
52: SET Asylum, RE: Power valves, the effect on the sound (if any) (0.00)
Posted by Michael V on 2010-04-28, 16:00:05 (71.178.120.235)
You can expect, in my experience, similar sonic changes as you hear swapping signal tubes. At the same magnitude, if not greater. I have no idea how to explain this, and I wish someone would come up w .......
53: High Efficiency Speaker Asylum, RE: bolero 890c tweeters (0.00)
Posted by Michael V on 2010-04-05, 11:28:48 (209.183.200.178)
I have a pair of the originals, please contact me privately. .......
54: General Asylum, D (0.00)
Posted by Michael V on 2010-03-30, 13:45:14 (209.183.200.178)
Because the difference between Moderate and Exceptional speakers is relatively minor, while the price difference is major. There are many moderately priced speakers that are extremely satisfying. ::: .......
55: Tube DIY Asylum, RE: AVC newby considering trying it...suggestions welcome (0.00)
Posted by Michael V on 2010-02-04, 06:53:18 (209.183.200.178)
Steve Eddy, You seem to want to criticize some common misconception here that hasn't been elicited. What exactly is the misconception? thanks .......
56: K&K Audio / Lundahl Transformers, RE: Dimensions (0.00)
Posted by Michael V on 2010-01-08, 06:58:37 (209.183.200.178)
My picture isn't clear, but the board is exactly the height of my chassis - so I would need a taller wood base and find a way to mount the board at least 1/2" off the back metal panel. None of that is .......
57: K&K Audio / Lundahl Transformers, Dimensions (0.00)
Posted by Michael V on 2010-01-07, 18:43:44 (71.191.102.216)
Kevin, the Mk III board looks a bit wider than the original - is that correct? I'm interested in upgrading but any extra width just won't fit in my chassis. In fact I don't think there's room for anyt .......
58: K&K Audio / Lundahl Transformers, To clarify.. (0.00)
Posted by Michael V on 2010-01-07, 18:13:43 (71.191.102.216)
"OK, I thought I read somewhere to adjust the plate voltage. But then my memory isn't what it used to be :)) So, adjust for current between the cathode and the CCS?" What you read was probably for add .......
59: Tube DIY Asylum, RE: Cap voltage rating (0.00)
Posted by Michael V on 2010-01-03, 07:52:41 (71.191.102.216)
200v may not be enough - it depends on your power supply and how quickly the B+ rises. If you use a DH rectifier like a 5R4, which heats up much faster than the 12b4, then your 200v caps will see the .......
60: Tube DIY Asylum, RE: Best grid stopper types? (0.00)
Posted by Michael V on 2009-09-26, 10:27:33 (71.178.137.188)
While carbon comp resistors may theoretically be the best at avoiding oscillations, IMO they all sound quite poor. I've had better success with Kiwame, Riken, Caddock, and even Mills WW resistors in t .......
61: Tube DIY Asylum, RE: Try AC (0.00)
Posted by Michael V on 2009-09-01, 17:32:52 (96.231.88.12)
I had a 20vac transformer but I think I ended up using a 47R dropping resistor. The 407a only draws something like 100ma. .......
62: Tube DIY Asylum, Try AC (0.00)
Posted by Michael V on 2009-09-01, 12:35:17 (96.231.229.101)
I would suggest trying AC. I don't have direct experience with the C3m, but I had the same decision to make with a 407a (20v heater version of the WE 396a) as the gain/output stage in my DAC. With AC .......
63: Tube DIY Asylum, RE: missunderstanding? (0.00)
Posted by Michael V on 2009-08-19, 13:17:53 (173.73.133.60)
This what I understood, as well. I just wondered if the other poster had some other basis for his comments. At 1kv, there are other issues including the wiring and tube sockets, but I still don't see .......
64: Tube DIY Asylum, Why? (0.00)
Posted by Michael V on 2009-08-18, 18:02:08 (71.178.143.96)
I've never seen any VR tube datasheet list a MAX voltage rating, only a minimum (as mentioned, for the purpose of igniting). What are they rated for, if less than 1000v? .......
65: Tube DIY Asylum, RE: Have you tried the silver? nt (0.00)
Posted by Michael V on 2009-08-07, 07:54:27 (96.231.216.162)
Understood. From my perspective, I've tried ONLY the silver RCA connectors and like them very much. Just wanted to clarify we're talking about different products. .......
66: Tube DIY Asylum, Have you tried the silver? nt (0.00)
Posted by Michael V on 2009-08-06, 05:15:09 (71.178.141.29)
.......
67: Tube DIY Asylum, Parts Connexion will start carrying them soon (0.00)
Posted by Michael V on 2009-08-05, 09:06:10 (71.178.141.29)
Or so they've been saying in their mass of emails this summer. I've only used the silver ones. Another thing I like about the CMC's...their design is very easy to solder with standard irons. ::: TOPIC .......
68: Tube DIY Asylum, RE: Fixed Resistor or Adjustment Pot on CCS (0.00)
Posted by Michael V on 2009-07-13, 15:59:55 (96.231.87.183)
"Is the difference in required resistance all due to the variability of the IXYS chips or to the differences between the tubes as well? I would think the chips should compensate for tube differences i .......
69: Tube DIY Asylum, RE: Fixed Resistor or Adjustment Pot on CCS (0.00)
Posted by Michael V on 2009-07-13, 14:17:32 (96.231.87.183)
"With the single chip, I've found I need about 272ohms on the left side and 300ohms on the right side to get 11mA, so if I use two of the same value resistors the currents will not be as closely match .......
70: High Efficiency Speaker Asylum, RE: altec 414z (0.00)
Posted by Michael V on 2009-07-11, 10:35:58 (96.231.87.183)
I did, thanks. Sounds like a neat project. .......
71: High Efficiency Speaker Asylum, RE: altec 414z (0.00)
Posted by Michael V on 2009-07-10, 21:53:03 (96.231.87.183)
How are you repairing the tweeters? 414Zs in a BR cab will reach 55-60 hz. I'd stick with something like the 614. .......
72: High Efficiency Speaker Asylum, RE: Gold plated tellurium copper for a lot less (0.00)
Posted by Michael V on 2009-07-07, 13:00:22 (96.231.87.183)
Thanks for the suggestion! .......
73: High Efficiency Speaker Asylum, RE: binding post (0.00)
Posted by Michael V on 2009-07-06, 22:00:49 (96.231.87.183)
Yes, those are fairly easy to solder. Unfortunately, they are the worst-sounding binding post I've ever used. I know thats not as helpful now... The cardas CCGR is very good, for just a little more $. .......
74: Tube DIY Asylum, RE: The Miracle of 2009 (0.00)
Posted by Michael V on 2009-06-18, 09:19:48 (96.231.172.194)
Agreed! The new site could use some refinement, but not having to write down all those parts numbers is a welcome development. .......
75: Tube DIY Asylum, RE: Trouble choke loading tube in regulated supply (0.00)
Posted by Michael V on 2009-06-09, 20:59:10 (96.231.174.98)
The poster above is spot-on, IMO. What is the voltage at C1 following the rectifier, with and without the input choke? Changing to choke-input will give you approx. 65% of the voltage you had with cap .......
76: Tube DIY Asylum, "...Altec (weak bass)," -- ?? (0.00)
Posted by Michael V on 2009-06-05, 18:43:40 (96.231.87.184)
What Altecs did you hear? They're great for low powered tube amps, though "honest" may not be the best way to describe them. Most would say they err on the side of warm and musical. .......
77: Tube DIY Asylum, RE: Schematic ? (0.00)
Posted by Michael V on 2009-06-05, 16:39:40 (96.231.87.184)
I wasn't planning to draw one out, but happy to provide details. It's a breadboard and the circuit is a work in progress... Right now it's a 2-stage with 403B driver, wired as triode and choke loaded. .......
78: Tube DIY Asylum, RE: Need help: Filament for 6B4G SE Parallel Amp (0.00)
Posted by Michael V on 2009-06-04, 21:34:05 (96.231.87.184)
"High Fidelity is more than a slogan. It means to be faithful to the source." Thanks, I always wondered about that. .......
79: Tube DIY Asylum, RE: Need help: Filament for 6B4G SE Parallel Amp (0.00)
Posted by Michael V on 2009-06-04, 20:07:32 (96.231.87.184)
I'm using fixed bias with a string of LEDs. .......
80: Tube DIY Asylum, RE: Need help: Filament for 6B4G SE Parallel Amp (0.00)
Posted by Michael V on 2009-06-04, 13:56:30 (96.231.87.184)
Separate filament transformers per channel aren't necessary - I'm heating stereo single-ended 46's with one 6A transformer. .......
81: High Efficiency Speaker Asylum, RE: Jensen PM woofer (0.00)
Posted by Michael V on 2009-06-02, 11:35:51 (96.231.84.95)
Nice find! That certainly validates your price estimate. I think you're right about the P15LL being a descendant of the A15. The frame seems to be identical to the P15 and typical of all other Jensen .......
82: High Efficiency Speaker Asylum, Jensen PM woofer (0.00)
Posted by Michael V on 2009-06-01, 21:49:34 (96.231.84.95)
Not arguing with your main point, but where do you come up with the valuation for the Jensen woofer? As far as I know, it's the model A15PM. I've never seen the A15 listed for sale. .......
83: K&K Audio / Lundahl Transformers, RE: New Cascode Surrent Source format now available (0.00)
Posted by Michael V on 2009-05-30, 09:57:45 (96.231.84.95)
Kevin, Thanks for the new CCS offering, I'll definitely be ordering some to try. Subjectively, how are the IXYS MOSFETs superior to the DN2540? The higher voltage rating is a big plus for use in shun .......
84: Tube DIY Asylum, RE: Alan Kimmel's FET load mu-stage vs. choke loaded mu-stage? Which? (0.00)
Posted by Michael V on 2009-05-26, 13:35:28 (96.231.84.95)
Mike C - was there a schematic posted here? It's not showing up for me. Thanks .......
85: Tube DIY Asylum, RE: What are YOU working on? (0.00)
Posted by Michael V on 2009-05-18, 14:40:34 (96.231.84.95)
Neat, what load and operating points did you choose for the 46's? I'm working on a 46 SET, and really like the tube so far. .......
86: Tube DIY Asylum, Nice audio dog (0.00)
Posted by Michael V on 2009-05-17, 21:09:17 (96.231.84.95)
Is that a dachshund??? .......
87: Tube DIY Asylum, RE: just a 5vac followup (0.00)
Posted by Michael V on 2009-05-09, 21:10:06 (71.191.98.136)
No, why not keep it simple? Use the 6.3vac to heat the EZ81. Then use the 5vac winding to get 6.3vdc for the ecc88s. With a cap input filter, you'll get around 7.0vdc at the output of the rectifer. It .......
88: Tube DIY Asylum, RE: just a 5vac followup (0.00)
Posted by Michael V on 2009-05-09, 16:31:49 (71.191.98.136)
see my response below... Yes, use a CRC with a 1 ohm resistor. .......
89: Tube DIY Asylum, RE: 6.3vdc from 6.3vac (0.00)
Posted by Michael V on 2009-05-09, 16:29:36 (71.191.98.136)
Is this a Hammond transformer? If so, just use the 6.3vac for the rectifier and the 5V supply for the ECC88's. After the rectifier, a simple CRC will be OK. Make the resistor 1 or 1.5R and your output .......
90: Tube DIY Asylum, RE: # 9 Pin ECC88/6DJ8 (0.00)
Posted by Michael V on 2009-05-08, 08:19:26 (71.191.98.136)
Surely you mean pin #9... .......
91: Tube DIY Asylum, Many Altec woofers were rated 99db+ NT (0.00)
Posted by Michael V on 2009-05-05, 12:48:56 (96.231.82.31)
.......
92: Tube DIY Asylum, RE: JEL phono problem.. (0.00)
Posted by Michael V on 2009-05-05, 09:39:02 (96.231.82.31)
You dont' need them across all the caps, I'd just advise using one on the biggest cap for safety. Drawing a few milliamps would be fine, so 100K. .......
93: Tube DIY Asylum, RE: JE Labs phono I plan on building (0.00)
Posted by Michael V on 2009-05-05, 09:36:09 (96.231.82.31)
I used one tube per audio stage, i.e. both channels in each tube. I can't say whether that's theoretically better or not, but as a result I don't have to find matched pairs, and can roll different 12S .......
94: Tube DIY Asylum, RE: JEL phono problem.. (0.00)
Posted by Michael V on 2009-05-04, 10:32:26 (96.231.82.31)
I'm not sure if you have any bleeder resistors in your PS, but the audio stages won't be drawing more than 6-8ma total. A 40ma power transformer should be loafing along there. You should measure the t .......
95: Tube DIY Asylum, RE: JEL phono problem.. (0.00)
Posted by Michael V on 2009-05-03, 19:00:43 (96.231.82.31)
What is the problem - not enough gain? What cartridge are you using? I built this design, except with a CCS on the second 6SL7 stage. It increases the gain, and at that current its mosfet has an outpu .......
96: High Efficiency Speaker Asylum, Have you listened to it?? (0.00)
Posted by Michael V on 2009-05-01, 23:27:05 (96.231.82.31)
You might think twice about selling... .......
97: K&K Audio / Lundahl Transformers, RE: Cascode DN2540 Problem (0.00)
Posted by Michael V on 2009-04-29, 11:37:58 (96.231.82.31)
Danl, What is the value of your bias resistors? There was a miswiring on an early version of the cascode boards, so double check the traces to make sure. If you do have the faulty vesions, it's real e .......
98: Tube DIY Asylum, RE: 12B4A LTP linestage (0.00)
Posted by Michael V on 2009-04-29, 10:36:43 (96.231.82.31)
Interesting - you never know til you try it. .......
99: Tube DIY Asylum, RE: While I'm asking all these questions???????? (0.00)
Posted by Michael V on 2009-04-27, 18:32:54 (96.231.82.31)
It does make sense to avoid using series resistors, but IME parallel resistors are OK. There's a neat program to help you find the right values, below. Looks like 18K and 27K in parallel gets you ther .......
100: Tube DIY Asylum, RE: 12B4A LTP linestage (0.00)
Posted by Michael V on 2009-04-27, 10:38:42 (96.231.82.31)
I overlooked the LTP reference in your description. It's not directly comparable to the Guinnevere, but I thought I remembered you use LTP drivers in most of your amps? It just doesn't make sense that .......
101: Tube DIY Asylum, RE: 12B4A LTP linestage (0.00)
Posted by Michael V on 2009-04-25, 21:52:35 (96.231.82.31)
Douglas, How would you compare this to the 12b4 Guinnevere? i.e. what is gained by moving the CCS to the cathode? Also, aside from simplicity what's the point of using the heater supply for the cathod .......
102: Tube DIY Asylum, Cinch (0.00)
Posted by Michael V on 2009-04-25, 21:45:47 (96.231.82.31)
The teflons are good, but I don't think they're any better than NOS Cinch sockets. Check out vacuumtubesinc.com for standard sockets at great prices. .......
103: Tube DIY Asylum, RE: Pre amp switching pop and dc offset (0.00)
Posted by Michael V on 2009-04-22, 20:44:00 (96.231.82.31)
Your post is confusing. First, explain what "mods" you have done and if you have a schematic, posting that would be helpful. Second, have you tried swapping tubes and measuring each stage to see if th .......
104: High Efficiency Speaker Asylum, AH-550 Azurahorns with small-format Altecs (0.00)
Posted by Michael V on 2009-04-20, 22:01:26 (71.178.134.202)
Interested in trying 802's on something other than Altec horns... I'm a horn novice but the Le Cleac'h expansion seems to be getting a lot of attention. Does anyone have experience or opinions on sma .......
105: Tube DIY Asylum, Same here! nt (0.00)
Posted by Michael V on 2009-04-18, 11:43:43 (71.178.134.202)
.......
106: SET Asylum, RE: DC coupled 2A3 amp with two rectifier tubes.... (0.00)
Posted by Michael V on 2009-04-17, 18:50:53 (71.178.134.202)
It should be safe as you describe, though I too would try to avoid any relay circuits. If you're really concerned, a damper diode for the 2A3 stage would perform the same function. By the way, I tried .......
107: Tube DIY Asylum, RE: 6AK5-45 (0.00)
Posted by Michael V on 2009-04-10, 20:25:03 (71.178.134.202)
That sounds like a really nice combo. I've used the 403A in triode, and it sounds great. Is its B+ really only 100v? If so, did you really intend such a low operating point? .......
108: Tube DIY Asylum, Maybe, maybe not (0.00)
Posted by Michael V on 2009-04-10, 10:43:29 (71.178.134.202)
Most audiophiles and DIYers are older, but anecdotally I remember seeing a surprising number of younger attendees at RMAF a couple years back. Considering that none could probably afford to buy anythi .......
109: Tube DIY Asylum, Is it audible at listening levels? (0.00)
Posted by Michael V on 2009-04-10, 07:55:12 (71.178.134.202)
Chris, Good info below - I would just clarify one thing. Is the hum/buzz audible within your normal listening range of the volume control? The Cornet has 44db gain, which is probably 5db or so more th .......
110: Tube DIY Asylum, Totally agree.. (0.00)
Posted by Michael V on 2009-04-07, 08:23:29 (71.178.134.202)
I would stay away from the later vintage of VR tubes (late 70's), however, since IME they seem to have much worse quality control. .......
111: Tube DIY Asylum, Power supply (0.00)
Posted by Michael V on 2009-04-05, 22:45:34 (71.178.134.202)
Dan, I'm not sure what your power supply looks like, but I had this exact set of symptoms with a 12SL7 phono stage. Turns out, it was all due to a 0A3 VR tube that liked to oscillate after being warme .......
112: Tube DIY Asylum, RE: Im trying to understand what your saying here. (0.00)
Posted by Michael V on 2009-04-03, 12:12:24 (71.178.141.65)
"so my question is why would the issue of any capacitance come into play on a choke input power supply?" There is no capacitor on the input of my power supply. My question which Thomas answered very w .......
113: Tube DIY Asylum, RE: Rectifiers w/ choke input (0.00)
Posted by Michael V on 2009-04-03, 11:04:39 (71.178.141.65)
Great, thanks for your post! .......
114: Tube DIY Asylum, RE: Rectifiers w/ choke input (0.00)
Posted by Michael V on 2009-04-03, 10:39:03 (71.178.141.65)
Thanks for your post. I just wondered if, on turn-on, the few seconds that it takes for my shunt regulator to draw enough current would cause much stress on the rectifier. Until it kicks in, the recti .......
115: Tube DIY Asylum, RE: Rectifiers w/ choke input (0.00)
Posted by Michael V on 2009-04-03, 10:30:30 (71.178.141.65)
The Hammond choke is ~90 ohms. Down the road I'll upgrade to something better, like from Intact Audio. I have (and have tried) the low DCR Triad chokes you recommended, but I'm going with a true chok .......
116: Tube DIY Asylum, Rectifiers w/ choke input (0.00)
Posted by Michael V on 2009-04-03, 09:18:11 (71.178.141.65)
I know this has been discussed before, but when a tube rectifier is used with a (true) choke input filter, can you completely ignore the 'maximum input capacitor' rating? I'm thinking of using the 5R4 .......
117: Tube DIY Asylum, RE: Paralleling resistors (0.00)
Posted by Michael V on 2009-03-27, 09:52:43 (71.178.141.65)
I can't answer whether multiple "generic metal film" resistors sound better than one, but I'm willing to bet a single Mills WW will sound better than either alternative. .......
118: SET Asylum, RE: Of course! (0.00)
Posted by Michael V on 2009-03-17, 16:15:34 (71.178.141.65)
Gerry- Thanks for the comments. I've heard your comment on globe 46's echoed elsewhere, so fortunately I've stayed away from them. I wouldn't be surprised if the RCAs sound the best; out of 19 total t .......
119: SET Asylum, RE: If 50 is the New 40, than 46 is the New 45! (0.00)
Posted by Michael V on 2009-03-17, 16:04:56 (71.178.141.65)
Good suggestion on changing rectifiers. I understand about P-K. From the schematic, there's already [I'm guessing] ~275v on the 45's plate. With a 46, that should increase 25-30 volts due to the diffe .......
120: SET Asylum, Of course! (0.00)
Posted by Michael V on 2009-03-16, 21:41:58 (71.178.141.65)
This is the SET Asylum after all. It will be driven by a WE 404a pentode (wired as triode) that should yield enough gain for a 2-stage integrated amp. I've been stocking up on ST 46s for over a year, .......
121: SET Asylum, RE: If 50 is the New 40, than 46 is the New 45! (0.00)
Posted by Michael V on 2009-03-16, 21:36:21 (71.178.141.65)
Very understandable - in this particular circuit the 46 probably has closer to 300 volts on its plate, which is well above the 250v maximum. IMO, it's probably worth checking. .......
122: SET Asylum, RE: If 50 is the New 40, than 46 is the New 45! (0.00)
Posted by Michael V on 2009-03-15, 23:19:48 (98.192.248.227)
Gerry, Thanks for your post. Putting aside the current rating, have you measured this amp's B+ voltages with the 46 in place? I'm afraid it is running very hard in this 45 circuit, without modificatio .......
123: High Efficiency Speaker Asylum, Vintage option (0.00)
Posted by Michael V on 2009-03-15, 08:42:17 (98.192.248.227)
If you're looking for a cheaper option, try a pair of Altec 403A wide rangers. They're at the low end of your sensitivity requirements, but are very affordable ($50-75/pair) and always available on eb .......
124: SET Asylum, RE: If 50 is the New 40, than 46 is the New 45! (0.00)
Posted by Michael V on 2009-03-14, 20:22:30 (98.192.248.227)
Thanks for the post. What operating points have you tried? The datasheet puts the max dissipation at ~5 watts, but I've also read that it can take much more. As your photo shows, the plate structure .......
125: Tube DIY Asylum, Muting switch (0.00)
Posted by Michael V on 2009-03-02, 12:32:26 (96.231.179.105)
You could install a muting circuit that removes itself after a delay, but I agree that (by far) the best solution is just to turn the amp off first. .......
126: Tube DIY Asylum, RE: Ques: Regards OPT plate voltage calcs? (0.00)
Posted by Michael V on 2009-02-15, 14:06:24 (71.178.133.71)
Robert - You need to account for the voltage loss in the output transformer, but the relevant number here is the OPT's primary resistance. The 5K number is the ac load impedance the 13EM7 will see. In .......
127: Tube DIY Asylum, RE: 0d3 operating values (0.00)
Posted by Michael V on 2009-02-07, 17:13:09 (71.178.133.71)
The 0d3 gas tube doesn't have any voltage limitations, since (by design) it will always drop ~150V. As long as you stay within the current range of the 0d3, the only rating you need to be concerned wi .......
128: Tube DIY Asylum, RE: New debate on regulation But maybe not! (0.00)
Posted by Michael V on 2009-02-07, 17:05:51 (71.178.133.71)
We're on the same page - when someone claims there is no audible difference, it says to me that they're either not a very good listener, or they didn't bother to do a real comparison. .......
129: Tube DIY Asylum, RE: New debate on regulation But maybe not! (0.00)
Posted by Michael V on 2009-02-07, 11:02:18 (71.178.133.71)
"He also said that if you can actually hear the difference between a good passive supply and a regulated one then the government wants to hire you to spy through walls on our enemies because your hear .......
130: K&K Audio / Lundahl Transformers, 1660 Imbalance? (0.00)
Posted by Michael V on 2009-02-01, 09:42:12 (71.178.133.71)
Kevin- I've had a nagging channel misbalance (left is slightly louder) which was never a huge deal, but I just realized that it may be related to my 1660/10ma IT's. This is a very simple 7044 -IT (Alt .......
131: Tube DIY Asylum, Great story! nt (0.00)
Posted by Michael V on 2009-02-01, 08:43:27 (71.178.133.71)
.......
132: Tube DIY Asylum, Great, thanks very much (0.00)
Posted by Michael V on 2009-01-20, 14:44:07 (71.178.135.223)
Just using the suggested pentode operating points (120v/7.5ma), the tube in triode looks to have a plate resistence around 4k, and an amplification factor of 47. Thanks again to you both. ::: TOPIC:: .......
133: Tube DIY Asylum, Thanks, but (0.00)
Posted by Michael V on 2009-01-19, 16:32:12 (71.178.135.223)
I didn't see any specs listed, just the triode curves. Is there a way to draw out the "faked triode" rp and mu from the pentode characteristics? .......
134: Tube DIY Asylum, 6AK5/408A in triode (0.00)
Posted by Michael V on 2009-01-19, 09:09:01 (71.178.135.223)
Hello, Does anyone know the gain and plate resistance of this tube when wired as a triode? I can't find this on any data sheets. Thanks! .......
135: Tube DIY Asylum, Probably (0.00)
Posted by Michael V on 2009-01-16, 22:14:32 (71.178.135.223)
DanL I appreciate skepticism, but maybe you should be skeptical of the skeptics. See the below link. In any event, it deserves a more disciplined investigation than your post above. Respectfully Micha .......
136: Tube DIY Asylum, Where do you get this information? (0.00)
Posted by Michael V on 2009-01-16, 17:32:46 (71.178.135.223)
>>Even though the global temperature is decreasing. >>Has been since 1999, but that is ignored. I've seen much info to the contrary. .......
137: General Asylum, Trip to New York (0.00)
Posted by Michael V on 2008-12-30, 08:15:59 (71.178.141.108)
Hello all, Visiting some friends in manhattan over New Year's, and will have some time to check out audio stores. Are there any good tubes/horns to hear in the city? Thanks in advance, Michael ::: TOP .......
138: High Efficiency Speaker Asylum, Altec 808-8A with 414Z (16ohm) (0.00)
Posted by Michael V on 2008-12-08, 15:58:54 (96.231.183.214)
Hello, I am trying to mate a 16-ohm woofer with an 8-ohm driver (it's an 808 with aluminum diaphragm from GPA, so essentially its an 802). In order to match impedances, I've calculated the attenuator .......
139: SET Asylum, RE: Any view on combination of 18w SET amp and Silver Iris 15'' open baffle (0.00)
Posted by Michael V on 2008-12-03, 06:40:54 (131.239.68.162)
No, just the challenge of recalculating the crossover. .......
140: Tube DIY Asylum, Thanks! (0.00)
Posted by Michael V on 2008-12-01, 07:38:30 (131.239.68.162)
Thats what I figured. I plugged it in yesterday, and it fired right up. So far it sounds pretty impressive, but I plan to also try some of Western Electric's other regulator tubes. Thanks again for yo .......
141: Tube DIY Asylum, Question on 427A voltage regulator (0.00)
Posted by Michael V on 2008-11-29, 19:09:32 (96.231.183.214)
Per the datasheet, this tube has a "Starter" electrode. I imagine its purpose is to help the tube ignite when the raw voltage is low. If that's not an issue, should it just be left disconnected? Thank .......
142: K&K Audio / Lundahl Transformers, FS: RAKK Passive Output Stage (0.00)
Posted by Michael V on 2008-11-25, 17:12:03 (66.119.35.104)
Hello, I've owned the RAKK Passive output stage for about 1.5 years, used off and on, and have decided to stick with an active output instead. Asking $200 obo. Thanks and happy holidays, Michael ::: .......
143: Tube DIY Asylum, RE: Resistor break-in PRP (0.00)
Posted by Michael V on 2008-11-23, 21:11:55 (71.178.120.39)
I have no way to explain break in, but I don't believe it's just the solder joint. I've had the same experience when using resistors in a crossover which didn't involve any soldering. .......
144: Tube DIY Asylum, Yep (0.00)
Posted by Michael V on 2008-11-23, 18:40:49 (71.178.120.39)
I've found that resistors also need some time to "break in" but never very long - 24 hours at most. I can't say how long the PRPs take, since I only used them once and threw away the rest of my order .......
145: Tube DIY Asylum, RE: Big (tube) amps AND high-eff speakers! (0.00)
Posted by Michael V on 2008-11-23, 18:32:59 (71.178.120.39)
Michael, I've been working on something similar. My Altec 414's sound great up to 1200, but didn't like them crossed much higher than that. I settled on 1K for this combo (Altec 802 with 32A bent horn .......
146: Tube DIY Asylum, You're out of your element, Donnie (0.00)
Posted by Michael V on 2008-11-21, 08:17:10 (131.239.68.162)
Sorry, couldn't resist. First things first, are you sure this is the cathode resistor? I'm unfamiliar with your amp, and whether it uses fixed or cathode bias. From one of your photos, it looks like t .......
147: SET Asylum, RE: Any view on combination of 18w SET amp and Silver Iris 15'' open baffle (0.00)
Posted by Michael V on 2008-11-19, 06:54:54 (131.239.68.162)
"The bass for an open baffle speaker, does not want me looking to use a sub" Kinda OT, but did you compare the bass of the Sterling midwoofer to that of the SI? I suspect it would be more articulate, .......
148: SET Asylum, RE: Any view on combination of 18w SET amp and Silver Iris 15'' open baffle (0.00)
Posted by Michael V on 2008-11-19, 06:52:18 (131.239.68.162)
Just to clarify - the Sterlings are a completely different speaker than the Silver Iris, and at 5x the price, they really should perform at a much higher level. I used the 15" version, with all the mo .......
149: SET Asylum, RE: Any view on combination of 18w SET amp and Silver Iris 15'' open baffle (0.00)
Posted by Michael V on 2008-11-14, 13:48:20 (131.239.68.162)
Hello, I ran the Hawthorne SI's with a few different amplifiers, including a SE 2A3 which produced around 3 watts. That was enough power for me in medium-sized listening rooms. Unfortuately, power is .......
150: Tube DIY Asylum, PM sent (nt) (0.00)
Posted by Michael V on 2008-10-31, 11:18:55 (131.239.68.162)
.......
151: Tube DIY Asylum, RE: so far (0.00)
Posted by Michael V on 2008-10-31, 06:31:33 (131.239.68.162)
>>>Well, I don't have to. I don't sell anything; there isn't any business I am running to profit over what I happen to discover. As in, I don't release the stuff every time I sell a copy...:) >>>In a .......
152: Tube DIY Asylum, RE: so far (0.00)
Posted by Michael V on 2008-10-29, 09:53:59 (131.239.68.162)
I'm not taking sides, but I'm curious why you pester Dennis/Jeff for their design ideas yet fail to disclose your own? I am truly interested in seeing your design, not trying to be sarcastic. Regards .......
153: Tube DIY Asylum, RE: Q: Carol 12/3 600V wire from Home Depot... (0.00)
Posted by Michael V on 2008-10-23, 10:00:55 (131.239.68.162)
Maldar- I tried the lower voltage (300?) Carol wire, and it was a big disappointment. I made a power cord with it, and used it as an internal speaker wire. Although with open baffle, I suppose it's no .......
154: Tube DIY Asylum, Sounds interesting... (0.00)
Posted by Michael V on 2008-09-19, 13:50:48 (131.239.68.130)
Do you have a schematic? Thanks .......
155: Tube DIY Asylum, Me too.. (0.00)
Posted by Michael V on 2008-09-14, 18:41:40 (66.119.35.104)
7044 --> Lundahl 1660 --> 2A3 Wood base still in progress (Tiger maple in background) .......
156: SET Asylum, Just for kicks.. (0.00)
Posted by Michael V on 2008-09-04, 12:18:30 (131.239.68.130)
Try taking the output from the other side of the current-set resistor. Sounds much better with the DN2540's I use.. .......
157: Tube DIY Asylum, Dr. - please review the schematic more closely. (0.00)
Posted by Michael V on 2008-09-03, 08:03:07 (131.239.68.130)
And think about how the 45 is actually biased. .......
158: K&K Audio / Lundahl Transformers, Of course (0.00)
Posted by Michael V on 2008-09-02, 09:20:41 (131.239.68.130)
I've noticed some degree of change (not always for the better) during warm-up in most gear. But what I'm hearing with this 2A3 amp is a completely different phenomenon, and very distracting. As an asi .......
159: General Asylum, Audio stores in Philadelphia? (0.00)
Posted by Michael V on 2008-08-30, 07:22:26 (96.231.172.64)
Driving up today from Washington to see an old friend...any places not too far outside the city? Thanks in advance! .......
160: K&K Audio / Lundahl Transformers, RE: Blackgates (0.00)
Posted by Michael V on 2008-08-28, 11:57:08 (131.239.68.130)
Thanks for sharing your BG experiences. I had indeed read about these frustrations, but I've also heard amps with them that did not need any warm-up time. The way my amp is configured, it is just easi .......
161: K&K Audio / Lundahl Transformers, RE: Help! - two questions re: LL1660 (0.00)
Posted by Michael V on 2008-08-28, 11:09:15 (131.239.68.130)
Thanks Kevin. You are right that the IT is not the only variable here, I have been blaming it on the Blackgate power supply caps (this is also my first use of BG's). I have eliminated all the other su .......
162: K&K Audio / Lundahl Transformers, Help! - two questions re: LL1660 (0.00)
Posted by Michael V on 2008-08-28, 07:21:59 (131.239.68.130)
Kevin and others- I've been using a pair of LL1660 (Alt S config, 4:4.5) interstage transformers in my two-stage 2A3 amp, using a 7044 as the input/driver. The driver runs around 9ma/140v p-k, and the .......
163: Amp/Preamp Asylum, RE: Why is it called a LINE STAGE? (0.00)
Posted by Michael V on 2008-08-27, 14:27:15 (131.239.68.130)
My understanding is that the term "line stage" comes from their original purpose - driving voice signals across long telephone lines - in the early days of telecommunications. This required a little .......
164: Tube DIY Asylum, Not just Audio Note.. (0.00)
Posted by Michael V on 2008-08-26, 06:27:40 (131.239.68.130)
There are some impressive designers (Kara Chafee comes to mind) building great-sounding units with White Coffin resistors, nasty electrolytics, chokes >10ohm, etc. I remember seeing a DeHavilland prea .......
165: Tubes Asylum, Perhaps different AC Mains voltage? (0.00)
Posted by Michael V on 2008-08-20, 13:47:47 (131.239.68.130)
You say you moved, so it's just a thought. Most likely it sounds like a bad preamp tube. .......
166: Tube DIY Asylum, RE: Here is my 2A3 SE with EF37a driver 2 stage with pictures (0.00)
Posted by Michael V on 2008-08-20, 09:03:47 (131.239.68.130)
Very nice - got any underside pics? Would be interested in the power supply Regards .......
167: Tube DIY Asylum, RE: Check out (0.00)
Posted by Michael V on 2008-08-15, 11:44:17 (131.239.68.130)
Very interesting post. I seem to recall the oven method being recommended to "cure" microphonic tubes. Have you found this to work? I think we all have a Tung-Sol VT-229 or whatever that sounds great, .......
168: Tube DIY Asylum, Great, thanks.. (0.00)
Posted by Michael V on 2008-08-14, 07:32:29 (131.239.68.130)
I'm now trying one in my DAC output stage. It is optimized for a choke-loaded 7DJ8; with a single LED in the cathode, shunt regulated by a 0B2 gas tube/CCS. After doing some math, I swapped the 0B2 fo .......
169: Tube DIY Asylum, RE: Have you listened to the alternatives? (0.00)
Posted by Michael V on 2008-08-13, 05:58:14 (131.239.68.130)
Andy - this is obviously a difficult question since comparing C-input to L-input filters is never apples to apples. But what I have subjectively noticed in amps/preamps that used choke input, is a gre .......
170: Tube DIY Asylum, RE: You won't be disappointed. (0.00)
Posted by Michael V on 2008-08-12, 15:07:10 (131.239.68.130)
Thanks for the info. Since you appear to be the 6N6P expert, any idea what the Rp is at that current? .......
171: Tube DIY Asylum, Interested in your phono design. (0.00)
Posted by Michael V on 2008-08-06, 09:00:40 (131.239.68.130)
Would you mind sharing details? Regards .......
172: Tube DIY Asylum, Forums are what you make of them. (0.00)
Posted by Michael V on 2008-08-05, 14:49:22 (131.239.68.130)
"I.e., we provide cogent arguments to you demonstrating that fewer stages does not necessarily equal lower distortion, and you refute it by saying your ears disagree? What's the point in any of us hav .......
173: General Asylum, RE: Audio Stores in Washington D.C. ? (0.00)
Posted by Michael V on 2008-08-04, 09:42:25 (131.239.68.130)
Unfortunately, the Gaylord is not a "short taxi ride" from anything of interest. I live in Bethesda and when my firm held a conference this spring at the Gaylord, it took me nearly an hour to drive d .......
174: Tube DIY Asylum, It's a great combo. (0.00)
Posted by Michael V on 2008-08-03, 21:02:18 (71.191.99.239)
I'm using a 7044--> LL1660 IT --> 2A3 SE and it is a very nice setup. The 7044 sounds cleaner and more authoritative in my opinion, but the 5687 is a lot easier to find! With the Lundahl wired 4:4.5, .......
175: Tube DIY Asylum, Did you rewire the tube socket? (0.00)
Posted by Michael V on 2008-07-29, 08:45:25 (71.191.99.239)
ECC99 and the 5687 variants have different pin-outs. I wonder if that wasn't the problem with your 7119 samples. The ECC99 is otherwise similar to the 7119 electrically, and they should bias similarl .......
176: Tube DIY Asylum, Have you looked at the K&K Audio DAC? (0.00)
Posted by Michael V on 2008-07-27, 22:29:00 (71.191.99.239)
May not be your cup of tea, but I think it's a great value. Would be interested in your thoughts. .......
177: Tube DIY Asylum, I think the big improvements are in bass response (nt). (0.00)
Posted by Michael V on 2008-07-23, 06:30:24 (131.239.68.130)
.......
178: Tube DIY Asylum, RE: Drank some of the Kool Aid! (0.00)
Posted by Michael V on 2008-07-22, 14:21:53 (131.239.68.130)
Steve- Thanks for sharing. I am running something similar (300mh/6R - 47uf BG - 5H/90R - 47uf BG feeding stereo 2A3s), after trying a number of different PS configurations. FWIW, I did try replacing t .......
179: Tube DIY Asylum, RE: HELP... With A Budding Future Asylum Member (0.00)
Posted by Michael V on 2008-07-19, 15:52:59 (66.119.35.104)
They have a reputation for being "laid back" and I tend to agree. The CD tweeter seems to be the weak link - IMO, it lacks inner detail, soundstaging, and the excitement factor. Having said that, it's .......
180: Tube DIY Asylum, RE: HELP... With A Budding Future Asylum Member (0.00)
Posted by Michael V on 2008-07-19, 14:12:04 (66.119.35.104)
I would suggest starting with speakers that you actually LIKE, since they kinda define the rest of your system. There are decent budget options out there - for instance the Hawthorne Silver Iris drive .......
181: General Asylum, RE: HiFi shops in DC or near Metro stops in MD or VA? (0.00)
Posted by Michael V on 2008-07-18, 11:12:23 (131.239.68.130)
I agree that Deja Vu is the best in the area - Vu is quite a character. His store is the SET/HE speakers type. I live in Bethesda but never seem to visit JS Audio. IIRC, they are of the more high-powe .......
182: Tube DIY Asylum, RE: Worthwhile Or A Waste Of Time? (0.00)
Posted by Michael V on 2008-07-14, 18:50:50 (71.191.99.239)
If you were thinking of trying to fit a tube phono stage in there... I just don't see the real estate. I notice the modular SS phono board, but for $199 and the hassle of installation, I agree with th .......
183: Tube DIY Asylum, RE: Use a pair of 100 mfd Solens (0.00)
Posted by Michael V on 2008-06-17, 17:07:10 (71.178.128.232)
Agreed! .......
184: SET Asylum, Totally agree (nt) (0.00)
Posted by Michael V on 2008-06-10, 09:50:09 (131.239.68.130)
.......
185: Tube DIY Asylum, For economics, why not 6SN7. (nt) (0.00)
Posted by Michael V on 2008-05-29, 08:37:28 (131.239.68.130)
.......
186: Tube DIY Asylum, Have your cake and eat it too. (0.00)
Posted by Michael V on 2008-05-29, 08:34:08 (131.239.68.130)
I believe some high-end designers have a "direct input" option that allows you to bypass all amplification. You would want separate output jacks, but that will allow you to switch from active-passive .......
187: Tubes Asylum, Thanks (0.00)
Posted by Michael V on 2008-05-29, 05:34:38 (131.239.68.130)
That's how I expected the Sovteks to compare w/ the JJs. I just have a hard time going back to JJ tubes, after experiencing so many EL34 failures with JJ. The EMLs are definitely not for me! ::: TOPI .......
188: Tube DIY Asylum, Send me your email. NT (0.00)
Posted by Michael V on 2008-05-28, 18:29:47 (131.239.68.130)
.......
189: Tubes Asylum, RE: In my system. . . (0.00)
Posted by Michael V on 2008-05-28, 07:53:40 (131.239.68.130)
I say go for the JJs. Might be a better use of funds to try tweaking the front end though, which IME has just as much impact on sonics as the outputs. Best of luck Michael .......
190: Tube DIY Asylum, RE: Giving in and building a preamp. What might suit my uses? (0.00)
Posted by Michael V on 2008-05-28, 07:18:29 (131.239.68.130)
Adam, the way I see it you have two options: 1) Use the 6SN7s and send me the 12b4's 2) Build a 12b4 Guinnevere (by Douglas aka Sector7g). I think it's a fantastic sounding circuit, and have built two .......
191: Tubes Asylum, RE: In my system. . . (0.00)
Posted by Michael V on 2008-05-27, 11:49:11 (131.239.68.130)
Larry I, Thanks for posting. Have you compared the JJs to Sovteks or Chinese 2A3's? Regards Michael .......
192: Tube DIY Asylum, RE: Jensen 47+47µF (0.00)
Posted by Michael V on 2008-05-27, 06:06:16 (131.239.68.130)
I tried one of the Jensen electrolytics, and was disappointed. I would take a Panasonic TSHA over these any day. Regards Mike .......
193: High Efficiency Speaker Asylum, Great reference! (nt) (0.00)
Posted by Michael V on 2008-05-13, 09:47:57 (131.239.68.130)
.......
194: Tubes Asylum, Yes... (0.00)
Posted by Michael V on 2008-05-13, 04:08:05 (131.239.68.130)
Sorta. The 7044 has slightly more gain and transconductance, and I've found biases a little differently than 5687 types (draws more current in the same fixed bias circuit). As to brands, the readily a .......
195: Tube DIY Asylum, Source component design (0.00)
Posted by Michael V on 2008-05-07, 08:59:17 (131.239.68.130)
Dennis- First, your posts on power amp and power supply design have been very interesting to read, thank you. "If you enlist the services of a good computer, and do nothing but sample and convert to a .......
196: Tube DIY Asylum, RE: AK fest.. (0.00)
Posted by Michael V on 2008-05-05, 09:52:40 (65.220.21.3)
Did anyone visit the Hawthorne Audio room? Any impressions? I am curious if they had the recently released Sterling Silver Iris drivers on exhibit. Thanks, Mike .......
197: SET Asylum, Judging a speaker by its FRP (0.00)
Posted by Michael V on 2008-05-02, 14:07:17 (131.239.68.130)
Dan- Just to back up RGA- I've heard the AN-E numerous times in my local Hi-fi store, driven by SET, and IMO the highs are incredibly smooth and non-fatiguing. .......
198: SET Asylum, RE: One needs 95 dB to get into high end audio??? (0.00)
Posted by Michael V on 2008-05-02, 09:47:59 (131.239.68.130)
Andy, Personally, I haven't heard enough speakers to make that kind of sweeping statement. But here's my take. Hi-end audio should be fun, and for me, building/contemplating amps is fun. 95db opens up .......
199: SET Asylum, Bose reference (0.00)
Posted by Michael V on 2008-05-02, 07:18:14 (131.239.68.130)
Now that is just mean. .......
200: Tube DIY Asylum, RE: Hammond 193L choke polarity (0.00)
Posted by Michael V on 2008-04-28, 06:29:28 (131.239.68.130)
Thanks for sharing. I once tried reversing a power supply choke - might have been in a preamp - and didn't notice any difference. I am one of those unfortunate DIYers who hear differences in hook-up w .......
201: Tube DIY Asylum, What exactly is your point here? (0.00)
Posted by Michael V on 2008-04-23, 10:05:35 (131.239.68.130)
Because previous generations were ignorant of occupational safe and healthy factors, we should be too? Or that because - anectodally - this video's lightkeeper and his assistant both lived long, healt .......
202: K&K Audio / Lundahl Transformers, RE: SE GM-70 monoblock amplifier - photo (0.00)
Posted by Michael V on 2008-04-22, 19:09:30 (66.119.35.104)
Is that a prototype of the same amp used at RMAF last year? I was very, very impressed with the sound of that system. Best, Mike .......
203: Tube DIY Asylum, Have you used one? NT (0.00)
Posted by Michael V on 2008-04-22, 09:43:59 (131.239.68.130)
.......
204: Tube DIY Asylum, Incorrect (0.00)
Posted by Michael V on 2008-04-13, 21:24:53 (66.119.35.104)
Unless I'm mistaken, 5Y3GT and 5R4 have the same pinout: 4&6 are plates, 2&8 are filaments. .......
205: Tube DIY Asylum, RE: 5y3 vs 5r4 (0.00)
Posted by Michael V on 2008-04-13, 18:54:31 (66.119.35.104)
Walt, You should be measuring the DC voltage with all tubes in place, including the rectifier. Without any rectifier, there should be only AC from the transformer. It's possible the 58v was present fr .......
206: Tube DIY Asylum, RE: Power supply challenge.... (0.00)
Posted by Michael V on 2008-04-10, 09:42:02 (131.239.68.130)
Hello, Since the input choke has nowhere near critical inductance for "true choke input" operation, wouldn't 1000uf be way too much for the 5u4 to work into? Thanks a lot Mike .......
207: Tube DIY Asylum, RE: Has anyone tried gas regulator tubes in a phono stage? (0.00)
Posted by Michael V on 2008-04-07, 05:39:27 (131.239.68.130)
Brian - I've used them in shunt regulators for two phono stages, and they work great. I installed a simple DN2540 CCS feeding a 0D3 tube into one of Thorsten's circuits, which was supplying the V1 12A .......
208: SET Asylum, Are you sure about that? (0.00)
Posted by Michael V on 2008-03-27, 11:09:30 (131.239.68.130)
My understanding is that Sovtek 2A3s and 6B4s have a plate structure that can take many more watts than typical 2A3s. Their voltage rating is higher (450 max), as Sovtek claimed on the datasheet (try .......
209: SET Asylum, Agreed - the Dehavilland room was great. NT (0.00)
Posted by Michael V on 2008-03-25, 05:47:43 (131.239.68.130)
.......
210: Tube DIY Asylum, Well said. nt (0.00)
Posted by Michael V on 2008-03-10, 12:18:21 (131.239.68.130)
.......
211: Tube DIY Asylum, RE: I would like some feedback on the Mundorf Silver Supremes (0.00)
Posted by Michael V on 2008-03-03, 15:07:32 (131.239.68.130)
I've heard the Mundorf and Dynamicap, and I think you are moving in the wrong direction. These Mundorfs are overall pretty neutral, but for $38 or whatever each that is not enough. They are a little .......
212: SET Asylum, Nice pic! It's a pretty tube. NT (0.00)
Posted by Michael V on 2008-03-03, 11:18:01 (131.239.68.130)
.......
213: SET Asylum, RE: Wow. (0.00)
Posted by Michael V on 2008-03-03, 06:31:46 (131.239.68.130)
Very interesting, I've used this tube for years now and never read this before. I wonder if the difficulty in matching both G-K elements would account for the reports of noisy samples or frequent duds .......
214: SET Asylum, RE: Wow. (0.00)
Posted by Michael V on 2008-03-01, 19:50:08 (71.178.134.65)
Dave - wondered if you could explain what you mean by 'effectively two tubes in parallel.' I've always wondered about the dual grid pins. Thanks .......
215: Tube DIY Asylum, RE: Hashimoto Transformers? (0.00)
Posted by Michael V on 2008-02-29, 06:52:42 (131.239.68.130)
I noticed Hashimoto OPTs in a local Hi-Fi store, Deja Vu. I didn't hear the amps, but Vu does not use bad iron! .......
216: Tube DIY Asylum, 'WE Sockets' from China (0.00)
Posted by Michael V on 2008-02-19, 05:48:04 (131.239.68.130)
You can find them at parts connexion and Angela Instruments. They are actually TOO tight until you man-handle them a bit. I use them for VR tubes, where I do not plan on rolling/replacing tubes often, .......
217: Tube DIY Asylum, They are electrically the same tube. (0.00)
Posted by Michael V on 2008-02-13, 14:48:04 (131.239.68.130)
To answer your question, specs like heater current would be verified on the datasheet for the tubes in question, rather than the amp's schematic. The power required to light the filaments/heaters is a .......
218: Tube DIY Asylum, Okay, but.. (0.00)
Posted by Michael V on 2008-01-25, 05:59:29 (131.239.68.130)
How do you know it's not just the effect of having a carbon comp resistor right in the signal path? IME, carbon comps are the sonic equivalent of sandpaper - they smooth off all the edges (and frequen .......
219: Tube DIY Asylum, What do you need? (0.00)
Posted by Michael V on 2008-01-22, 14:32:23 (131.239.68.130)
I use this in my linestage, supplying around 50ma, but with a 5R4 rectifier. In my case, I have 325vdc output from the rectifier. Unfortunately I can't recall the AC voltage, which is the most helpfu .......
220: Tube DIY Asylum, Why not just try it (with a small input cap)? (0.00)
Posted by Michael V on 2008-01-18, 10:43:00 (131.239.68.130)
Unless you are drawing close to the VA ratings, it might not be far off. As already pointed out, you should have a very small input cap just to preserve your rectifier investment. Doesn't seem to be a .......
221: Tube DIY Asylum, Have to disagree (0.00)
Posted by Michael V on 2007-12-09, 12:55:25 (66.119.35.104)
With all due respect, I think there's a lot more to connectors than impedance. I'm not qualified to speak to the other factors that make different wire/connectors sound different, but here's what I've .......
222: Tube DIY Asylum, RE: Bleeders (0.00)
Posted by Michael V on 2007-12-07, 13:41:32 (131.239.68.130)
Yes, even the 12W Mills. .......
223: Tube DIY Asylum, RE: The rest of the parts: ALLIED Electronics / M. Percy (0.00)
Posted by Michael V on 2007-12-07, 09:12:19 (131.239.68.130)
I don't use clip leads, and I've also found that bleeders have an adverse effect. Just one more coloration. .......
224: Tube DIY Asylum, Please elaborate (0.00)
Posted by Michael V on 2007-12-06, 15:00:43 (131.239.68.130)
Bruce, I appreciate your post. I've been breadboarding a SE 2A3 amp, and I've been experimenting with various lineups of chokes and capacitors. Presently I have a Hammond 159ZC (60mh/2A/.7R) quasi-inp .......
225: Tube DIY Asylum, I second the K&K boards, (0.00)
Posted by Michael V on 2007-11-15, 08:47:47 (131.239.68.130)
They work very well and I think Kevin is doing a great service to DIYers by offering them at such a reasonable price. He fit the cascode circuit on roughly the same board as the single mosfet version, .......
226: Tube DIY Asylum, RE: 5687 (0.00)
Posted by Michael V on 2007-11-09, 10:34:53 (131.239.68.130)
Hey, that JAN Phillips is no slouch. Considering they're probably the cheapest, most available 5687, that says something about the 5687. .......
227: Tube DIY Asylum, Thanks for posting... (0.00)
Posted by Michael V on 2007-11-01, 07:35:10 (131.239.68.130)
One question - what is your total current draw? 90ma or so? What if you change the driver's supply to just an R-C (following the OPT taps)? .......
228: Tube DIY Asylum, RE: Need a little help... (0.00)
Posted by Michael V on 2007-10-25, 14:07:24 (131.239.68.130)
Maybe it would be easier to help if you described the noise problem. Assuming you meant to type 228 instead of 2218 (THAT would indicate a problem), the voltages are in the ballpark. Mike ::: TOPIC:: .......
229: Tube DIY Asylum, RE: Interesting ... (0.00)
Posted by Michael V on 2007-10-22, 08:17:08 (131.239.68.130)
While I think it's usually crazy to speculate about a circuit without seeing 'under the hood,' Dennis has been very forthcoming about how he builds amplifiers, so I dont' see any great mystery here. I .......
230: Tube DIY Asylum, Agreed (0.00)
Posted by Michael V on 2007-10-22, 06:52:23 (131.239.68.130)
Paul, I heard them Friday and again on Saturday, and that room was very impressive. I really liked the natural, effortless dynamics. I can't say it was the best sounding room in Denver, but it wasn't .......
231: SET Asylum, RE: Switching to a 845 amp (0.00)
Posted by Michael V on 2007-10-19, 07:00:52 (131.239.68.130)
Tubers, I heard a number of 845 amps at RMAF, and every time (except for the Bastanis room) I noticed a rich, visceral quality to the midrange/midbass. That might not be everyone's cup of tea, but it .......
232: Tube DIY Asylum, Try it! (0.00)
Posted by Michael V on 2007-10-17, 08:06:39 (131.239.68.130)
You might be surprised what you can hear... .......
233: SET Asylum, 5676 (0.00)
Posted by Michael V on 2007-10-16, 12:10:30 (131.239.68.130)
Andy, What kind of life have you been getting from our 5676's? I noticed on one datasheet that they're rated for only 100 hours. Thanks Mike .......
234: SET Asylum, RE: First SET amp experiences (0.00)
Posted by Michael V on 2007-10-11, 07:31:42 (131.239.68.130)
Hey Andy- How do you like those 46's? I've always expected they would be an excellent driver for a 300B. Not much gain there, right? Best, Mike .......
235: SET Asylum, Thanks (0.00)
Posted by Michael V on 2007-10-05, 07:30:52 (131.239.68.130)
Thanks for the report! When I start building I will use Sovteks, because they're cheap, and try the JJ's once everything seems to be working properly. Best, Michael .......
236: SET Asylum, 2.5v 300B tubes (0.00)
Posted by Michael V on 2007-10-03, 12:54:29 (131.239.68.130)
Thanks. The initial buzz seems to be strong, but every JJ tube I've used (E34L, GZ34, ECC99) has died prematurely. It's ok for $10 pentodes, but replacing 2A3's are a different story. Anyway, I see th .......
237: Tube DIY Asylum, RE: How to set up filament bias? (0.00)
Posted by Michael V on 2007-10-03, 07:04:37 (131.239.68.130)
Dave, Wouldn't the variation in filament current make it very difficult to keep the plate current accurate? A 1% variation in filament current would be a 40% change in plate current, right? Swapping .......
238: Tube DIY Asylum, RE: 90 tube amps (0.00)
Posted by Michael V on 2007-10-02, 14:47:43 (131.239.68.130)
Michael - don't worry, on this forum 'crazy' is a figure of merit! .......
239: SET Asylum, Have you tried the JJ? (0.00)
Posted by Michael V on 2007-10-02, 06:50:30 (131.239.68.130)
(not trying to be ironic) .......
240: Tube DIY Asylum, 90 tube amps (0.00)
Posted by Michael V on 2007-10-02, 06:19:45 (131.239.68.130)
That's quite a rotation! .......
241: Tube DIY Asylum, RE: JE Labs 300b Amp - Newbie questions (0.00)
Posted by Michael V on 2007-09-24, 13:31:37 (131.239.68.130)
Hey Doug, 1) The 68K and 23K resistors are plate load resistors for the 6SN7's, so their purpose is to provide a load impedance for the gain stages to work. You need the 390 (and ideally would want mo .......
242: Tube DIY Asylum, RE: Reliable U.S. source for reasonably-priced, but great-sounding, PIO caps? (0.00)
Posted by Michael V on 2007-09-24, 10:58:09 (131.239.68.130)
The ASC caps are popular, go to www.alliedelec.com and do a search. The prices are very reasonable, especially for the large values. Matching to specific crossover values may be an issue... It might h .......
243: Tube DIY Asylum, Ok, I'll bite. (0.00)
Posted by Michael V on 2007-09-12, 13:28:57 (131.239.68.130)
What kind of Russians should I try? Are they similar construction? Until recently I've never had a need for such low values. Maybe I'll try them for RIAA, too. TIA, Mike .......
244: Tube DIY Asylum, My short answer... (0.00)
Posted by Michael V on 2007-09-12, 13:20:48 (131.239.68.130)
I have no idea! Sorry, I haven't compared it to anything. It sounds very nice with PP 12V6, and I do plan to try other output tubes, particularly the 1626. Somewhere I read that the max DC current per .......
245: Tube DIY Asylum, RE: The most NEUTRAL coupling cap? (0.00)
Posted by Michael V on 2007-09-12, 08:40:01 (131.239.68.130)
The ZNs are indeed tonally neutral - to my ears - but perhaps TOO neutral. What I mean is they aren't quite as musical, maybe a tad Hi-Fi sounding. Right now I'm breaking in some Vcaps, which seem ver .......
246: Tube DIY Asylum, Follow up question (0.00)
Posted by Michael V on 2007-09-12, 08:13:32 (131.239.68.130)
I've always wondered: does the DCR change on the OPT windings? This would make balancing difficult obviously. On a similar circuit using a Dyna Z565, it doesn't seem to change much after 30 minutes of .......
247: Tube DIY Asylum, RE: The most NEUTRAL coupling cap? (0.00)
Posted by Michael V on 2007-09-12, 06:59:12 (131.239.68.130)
If you want to avoid warmth, don't bother with the Mundorf SIO caps. As others have commented, they're a bit underwhelming for the price - coming across mechanical and uninvolving. I'd second the Mund .......
248: Tube DIY Asylum, Phase does make a difference, but (0.00)
Posted by Michael V on 2007-09-11, 13:20:38 (131.239.68.130)
...sometimes I'm not sure which 'phase' I prefer. Tonal balance and spatial qualities can definitely change, but I wouldn't say either sounds 'wrong.' Just different. That's just my experience, FWIW e .......
249: SET Asylum, RE: Is A SET Amp the Only Way to Obtain Similer Benefits? (0.00)
Posted by Michael V on 2007-09-09, 16:16:42 (69.140.171.199)
I used the PSB 4T, an older version of the T45. I haven't heard yours, but the 4Ts are an excellent bargan for $2-300 used. I'm surprised anyone would prefer a SS amp with them... Anyway, a 5 watt PP .......
250: Tube DIY Asylum, What Shindo does? (0.00)
Posted by Michael V on 2007-09-04, 14:25:50 (131.239.68.130)
I noticed in Dudley's writeup of one of Shindo's amps that he uses an EY88 diode in the HV secondary (CT to ground). Somehow, that seems more appealing to me. .......
251: Tube DIY Asylum, Good question (0.00)
Posted by Michael V on 2007-08-28, 06:47:09 (131.239.68.130)
Rodney, I was hoping you'd get some responses, because I've always wondered the same thing. I've only used Hammond and Triad chokes, but all the major transformer manufacturers offer their own filter .......
252: Tube DIY Asylum, RE: 1st Project Wired, Chasing Hum (0.00)
Posted by Michael V on 2007-08-24, 11:21:57 (131.239.68.130)
Congrats on getting it wired up! Layout is one cause of hum, but I would check a few of the usual suspects before doing anything drastic. You said the hum disappears when you put pressure on the trans .......
253: Tube DIY Asylum, Dave Cigna's post (0.00)
Posted by Michael V on 2007-08-14, 10:17:39 (131.239.68.130)
Andrew, Before trying anything else, I think you should reconcile Dave's comments below. It seems that something on the driver stage is miswired and/or measured incorrectly. What are the voltages on e .......
254: SET Asylum, Thanks everyone. (nt) (0.00)
Posted by Michael V on 2007-08-06, 11:33:24 (131.239.68.130)
.......
255: Tube DIY Asylum, RE: 4uf cap vs. 47uf cap in 1st position in CLC filter...will output voltage remain the same? (0.00)
Posted by Michael V on 2007-08-03, 06:53:22 (131.239.68.130)
Does using a small C1 make it any easier on the power transformer? .......
256: SET Asylum, RE: 2A3 Output Transformers:For Cheap use Hammond 125FSE (0.00)
Posted by Michael V on 2007-08-02, 06:35:16 (131.239.68.130)
Thanks for the suggestion, I'll have to look into this more. Hammond's website says these 'are not for Hi-Fi use' but I suppose that is just because of the bandwidth? Down to 100hz is fine for my pla .......
257: SET Asylum, RE: 2A3 Output Transformers (0.00)
Posted by Michael V on 2007-08-01, 08:48:06 (131.239.68.130)
Thanks for the suggestions. Parafeed has always appealed to me, but I wonder if I can get some of the same benefits by using a small-ish OPT. .......
258: SET Asylum, 2A3 Output Transformers (0.00)
Posted by Michael V on 2007-08-01, 07:41:26 (131.239.68.130)
Hello, I'm hoping for some sage advice on OPTs. I plan to build a 2A3 SET to drive a widerange driver on open baffle. The bass will be augmented below ~80hz, so LF extension in the 2A3 amp (hence OPT .......
259: Tube DIY Asylum, RE: Multiple Pre Outputs/ Bi-Amping (0.00)
Posted by Michael V on 2007-07-26, 14:28:51 (131.239.68.130)
Thanks Tre'. I was just wondering if anybody had found them beneficial in practice. I'll try separate caps and see what that does. Best, Mike .......
260: Tube DIY Asylum, RE: Multiple Pre Outputs/ Bi-Amping (0.00)
Posted by Michael V on 2007-07-26, 11:16:15 (131.239.68.130)
Hi Tre', So you just have both output caps from the same output in your audio stage? Is there any merit to using series resistors a la Voltsecond? .......
261: Tube DIY Asylum, RE: ASL AQ1002 amp bias trouble (0.00)
Posted by Michael V on 2007-07-26, 09:40:20 (131.239.68.130)
You said 'recently it blew a fuse'. After this incident, it's possible the bias-set resistor under that tube's cathode was also blown. Try measuring from Pin 8 to ground, and see if you are reading th .......
262: Tube DIY Asylum, RE: ASL AQ1002 amp bias trouble (0.00)
Posted by Michael V on 2007-07-26, 09:25:39 (131.239.68.130)
Hey Tom, Sounds like a tube problem. Are you able to bias both channels' power tubes to the proper current? What happens when you swap tubes between channels? .......
263: Tube DIY Asylum, Multiple Pre Outputs/ Bi-Amping (0.00)
Posted by Michael V on 2007-07-26, 08:25:15 (131.239.68.130)
Hello, I've been experimenting with open baffle speakers recently, and just added an Augmentation woofer to the [otherwise] fullrange coaxial. I'm using a 150W plate amp to power the Augies, and my ma .......
264: Tube DIY Asylum, RE: Mundorf M-Lytics (0.00)
Posted by Michael V on 2007-07-17, 10:58:28 (131.239.68.130)
C.Y, That's good to hear. Short of Black Gates, there really isn't much to choose from. Care to comment on what type of sound they have? I like the sound I'm getting from their silver/oil and ZN type .......
265: Tube DIY Asylum, Mundorf M-Lytics (0.00)
Posted by Michael V on 2007-07-17, 06:05:38 (131.239.68.130)
Nicely done! I like the simplicity, too. I noticed the Mundorf electrolytics - what is your opinion of them? I have one sitting around that I haven't tried yet. Best, Mike .......
266: Tube DIY Asylum, Thanks. (nt) (0.00)
Posted by Michael V on 2007-07-10, 12:12:36 (131.239.68.130)
.......
267: Tube DIY Asylum, RE: Maximum Capacitance for Damper Diodes (0.00)
Posted by Michael V on 2007-07-09, 13:35:15 (131.239.68.130)
Hi Tom, Would you please explain something: does your answer pertain to doubler circuits specifically, or all cap input supplies? I've just followed the rectifier datasheet guidelines for max input ca .......
268: K&K Audio / Lundahl Transformers, RE: A Few Basic RAKK questions (0.00)
Posted by Michael V on 2007-07-06, 10:40:53 (131.239.68.130)
Thanks, Dave. I was wondering about that, too. I guess that's how the RAKK clock is powered up? .......
269: K&K Audio / Lundahl Transformers, A Few Basic RAKK questions (0.00)
Posted by Michael V on 2007-07-05, 09:30:06 (131.239.68.130)
Hello, I've acquired a used Mk 1 DAC board, to see if your design is something I want to invest in. I have a few questions that may be too obvious to have been covered already: 1. I am starting with a .......
270: Tube DIY Asylum, RE: Looking for some sage advice on parts selection for a Hagerman Cornet II (0.00)
Posted by Michael V on 2007-07-04, 12:21:54 (69.140.152.206)
Tubesforever, I used Hovland (.1) and Multicap output caps, and a mix of different resistors (Kiwame, Vishay, Holco, Roederstein, Caddock for the 47K). I would recommend Mills for plate loads, B+ load .......
271: Tube DIY Asylum, RE: Question: combined heaters (0.00)
Posted by Michael V on 2007-06-27, 12:11:23 (131.239.68.130)
You might be fine, but there's another consideration. The datasheet says to keep the h-k potential as low as possible, so maybe you would be shortening the lives of your previous 27's. I've considered .......
272: K&K Audio / Lundahl Transformers, RE: 6N6P test results (0.00)
Posted by Michael V on 2007-06-27, 10:16:07 (131.239.68.130)
Yes, I can't recall the ebay seller for my tubes but I'll forward his details if they turn out to be decent samples. .......
273: K&K Audio / Lundahl Transformers, RE: 6N6P test results (0.00)
Posted by Michael V on 2007-06-27, 08:28:04 (131.239.68.130)
I would agree with the garbage statement. Do they have the OTK stamp indicating they passed Russian QC? I've read that failing samples frequently resurface on ebay. Also: apparently they have lower th .......
274: Tube DIY Asylum, RE: CCS loaded 6SN7 driver, switch off pulse. (0.00)
Posted by Michael V on 2007-06-26, 07:17:46 (131.239.68.130)
Martin, I have the same issue, see the linked thread. I'm not familiar with the Lowthers but it might be helpful to know their power handling. My old speakers (PSB 4T) had the same large woofer excurs .......
275: K&K Audio / Lundahl Transformers, Great, thanks! (0.00)
Posted by Michael V on 2007-06-23, 14:47:39 (69.140.152.206)
.......
276: K&K Audio / Lundahl Transformers, RE: Calculating I/V resistor for RAKK DAC (I) (0.00)
Posted by Michael V on 2007-06-23, 10:44:22 (69.140.152.206)
Thanks! So, if I were to load the same tube with a LL1660 (line output - Alt Q) with a 4.5:1 stepdown, would the I/V resistor be around 400 ohms now? Is there an upper limit to the R value you'd rec .......
277: K&K Audio / Lundahl Transformers, Calculating I/V resistor for RAKK DAC (I) (0.00)
Posted by Michael V on 2007-06-22, 19:46:19 (69.140.152.206)
Hello, I've been searching the forum but can't seem to understand the math here. There's a few active output stages I'd like to try with the RAKK DAC, but I'd like to keep the output voltage at the 2v .......
278: Tube DIY Asylum, Great description of JJ KT77. (0.00)
Posted by Michael V on 2007-06-12, 10:38:02 (131.239.68.130)
Detailed, but not terribly involving IMO. This was in a Dynaco 70 w/Triode input board, and I just kept going back to JJ's E34L. Best, Mike .......
279: K&K Audio / Lundahl Transformers, Error on Cascode CCS boards (0.00)
Posted by Michael V on 2007-06-09, 11:37:19 (69.140.152.206)
Kevin, I think there may be a trace error on the new boards. I've been using a pair on the output of my 12SL7 phono stage without any problem. But it seems the fixed Rset goes to the wrong side of the .......
280: K&K Audio / Lundahl Transformers, RE: FS: Rakk DAC and PSU (MK1) (0.00)
Posted by Michael V on 2007-05-29, 12:46:15 (69.140.152.206)
OK, I'm interested. Please email me. .......
281: K&K Audio / Lundahl Transformers, RE: FS: Rakk DAC and PSU (MK1) (0.00)
Posted by Michael V on 2007-05-27, 10:22:45 (71.200.92.189)
Do you have the original instructions? Please email me at vorhismj at hotmail. Thanks Mike .......
282: Tube DIY Asylum, RE: V-cap OIMP - impressions (0.00)
Posted by Michael V on 2007-05-25, 07:40:32 (131.239.68.130)
Bernard, You definitely need to know the value of the following (presumably output) stage grid resistor, to calculate bass roll-off. 10uf is very large for a coupling cap so there could be other consi .......
283: Tubes Asylum, 12BH7 and 12AU7 (0.00)
Posted by Michael V on 2007-05-24, 20:25:11 (69.140.152.206)
The 12bh7 and 12au7 do have the same pinout, so it might be possible to use either in your amp. But they are different tubes with different optimal operating points, so you should check with your manu .......
284: Tubes Asylum, Agreed. (0.00)
Posted by Michael V on 2007-05-24, 14:15:58 (131.239.68.130)
Fortunately, it's not the other way around. Rectifiers and signal tubes should live a lot longer than output tubes. .......
285: Tube DIY Asylum, Re: Convertible Amplifier (0.00)
Posted by Michael V on 2007-05-04, 08:34:37 (131.239.68.130)
The amp is very quiet, but I can hear the faintest amount of hum only when using my favorite 12SN7 (of course). It is dead quiet with all other tubes. I use a 1uf snubber capacitor, but noise wasn't a .......
286: Tube DIY Asylum, Re: Convertible Amplifier (0.00)
Posted by Michael V on 2007-05-04, 06:32:58 (131.239.68.130)
I had the same idea for my 12SN7-12V6 amp, but I got lazy and didn't include the switches! I am using an Amveco toroid for the AC heaters. It has 7+7 secondaries that I wire in series (with small dro .......
287: Tube DIY Asylum, 2nd the Kiwames- with caveat (0.00)
Posted by Michael V on 2007-04-23, 18:26:34 (69.140.152.206)
I've been very pleased with Kiwames too, but not when they see any real current. As gridstopper, input/output loading, or RIAA equalization resistors, they have a nice blend of openness and warmth. Bu .......
288: Tubes Asylum, Re: Kt-77 in St-70 (0.00)
Posted by Michael V on 2007-03-30, 07:27:00 (65.220.21.3)
My quad of JJ KT77's bias slightly higher than their E34L's in my 70. This might just be tube variation, though, since all my E34L quads have needed some adjustment. .......
289: Tube DIY Asylum, Re: New amp- damage during turn-off? (0.00)
Posted by Michael V on 2007-03-10, 20:19:29 (69.140.152.206)
Michael, I've measured a few times now, and it seems to be a small positive voltage of 30mv at most. The charge is so brief that it's difficult to measure. Does this make sense to you? Thanks ::: TOPI .......
290: Tube DIY Asylum, Schematic (0.00)
Posted by Michael V on 2007-03-09, 06:53:45 (65.220.21.3)
OK, here's the schematic: .......
291: Tube DIY Asylum, Re: New amp- damage during turn-off? (0.00)
Posted by Michael V on 2007-03-09, 06:34:31 (65.220.21.3)
That does make sense, thanks guys. I will measure the voltage tonight and post the results. Here is a schematic for the amplifier. As I mentioned above, each CCS is a DN2540 cascade. This being my fir .......
292: Tube DIY Asylum, Re: New amp- damage during turn-off? (0.00)
Posted by Michael V on 2007-03-08, 17:56:46 (69.140.152.206)
The 12v6's act as a sort of long tail pair themselves, with the CCS in the cathode attempting to force balance. With 'matched' pairs, they are within 1 or 2 ma in both channels. Since I am using a sep .......
293: Tube DIY Asylum, New amp- damage during turn-off? (0.00)
Posted by Michael V on 2007-03-08, 14:48:10 (65.220.21.3)
I'm having a strange problem with a newly built PP 12V6 amplifier. In lieu of the ability to post a schematic, it's simply an actively loaded 12sn7 cap-coupled to a pair of 12V6s with a CCS in their s .......
294: Inmate Systems, Michael V's Main (0.00)
Posted by Michael V on 2007-02-09, 08:41:41 (65.220.21.3)
To add your system, you must register .">
Audio Asylum Inmate Michael V's Main System
Home
/ FAQ
/ News
Classifieds
/ Events
.......
Found total of 294 records, Query: , Author: Michael V in All Forums, Time: 1 sec.