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1: Tubes Asylum, RE: Dyna ST-35 / Tube Glow (0.00)
Posted by Jim McShane on 2023-12-05, 20:08:04 (24.1.201.224)
It may be nothing of any consequence - check my Tube FAQ here at the Asylum. Item #7 may be what is happening in your amp. .......
2: Tubes Asylum, RE: Paging Jim McShane (0.00)
Posted by Jim McShane on 2023-11-04, 14:22:31 (24.1.201.224)
To do it right it would indeed require a high quality screen supply in addition to the Deuce's existing power supplies. Finding physical space for a new regulated screen supply could be a problem - it .......
3: Tubes Asylum, RE: The two thick pins are the heater. . (0.00)
Posted by Jim McShane on 2023-10-26, 17:11:04 (24.1.201.224)
Yes, it seems the tubes themselves are at fault, sorry to say. I'm glad I could help - but I sure wish you would have had a better outcome! .......
4: Tubes Asylum, RE: The two thick pins are the heater. . (0.00)
Posted by Jim McShane on 2023-10-25, 17:37:35 (24.1.201.224)
Either you have poor contact between the probes of your DMM and the tube pins or you (unfortunately!) have open heater circuits in the tubes themselves. If you put both probes on the SAME tube pin you .......
5: Tubes Asylum, RE: unkown tube (0.00)
Posted by Jim McShane on 2023-10-20, 18:10:06 (24.1.201.224)
It's definitely a 12BY7; and Japanese made tubes had the short plates, so the short plates in the tubes match up with the markings you found. I suspect it was a Japanese made tube possibly branded Wes .......
6: Asylum Feedback/Support, Mail Is Blocked (0.00)
Posted by Jim McShane on 2023-07-21, 12:25:41 (24.1.201.224)
Rod, I can't reply to the email you sent me on 7/20 - it is being blocked by the host at Audio Asylum. This was the only way I could reach you to let you know. Feel free to delete this post once you r .......
7: Tubes Asylum, RE: It was the tube. (0.00)
Posted by Jim McShane on 2023-05-27, 12:00:17 (24.1.201.224)
Just a reminder - if you are facing noise problems and you think it might be tube related check out my FAQ post. It may be helpful. .......
8: Tubes Asylum, RE: My RCA tube books are all packed up, but further internet searches seem (0.00)
Posted by Jim McShane on 2023-05-21, 12:51:46 (73.246.23.72)
Yes, use the 7591A data. .......
9: Tube DIY Asylum, RE: Q: Citation2 Build-Huge Phase Inverter DC Balance Runaway (0.00)
Posted by Jim McShane on 2023-03-21, 13:06:34 (73.246.23.72)
Thanks for clarifying that. Since your experience and mine are totally opposite I was afraid it would confuse people who own "genuine" Citation IIs. Best of luck with your project! .......
10: Tube DIY Asylum, RE: Q: Citation2 Build-Huge Phase Inverter DC Balance Runaway (0.00)
Posted by Jim McShane on 2023-03-20, 19:15:15 (73.246.23.72)
Again, a couple comments... The Cit II was guaranteed to be stable into any load, and even almost 60 years later I must say that unless I encounter a Cit II that is in absolutely horrible shape they .......
11: Tube DIY Asylum, RE: Q: Citation2 Build-Huge Phase Inverter DC Balance Runaway (0.00)
Posted by Jim McShane on 2023-03-20, 16:07:08 (73.246.23.72)
I was about to jump in and see if I could help when this post showed up. I just want to make a couple comments about this... 1. I STRONGLY recommend that you use/follow the original H-K schematic, not .......
12: Tubes Asylum, RE: tube sales (0.00)
Posted by Jim McShane on 2023-03-03, 13:43:38 (73.246.23.72)
I was only speaking for myself! There are Russian tubes available, but I'm not buying any. Other sellers/manufacturers may feel differently. .......
13: Tubes Asylum, RE: tube sales (0.00)
Posted by Jim McShane on 2023-03-02, 17:59:57 (73.246.23.72)
I am no longer selling the current production Russian made tubes. When my remaining current production (received pre-Ukraine invasion) Russian tube stock is gone, I will no longer be carrying Russian .......
14: Tube DIY Asylum, RE: Tube Prices UP! (0.00)
Posted by Jim McShane on 2023-02-14, 18:48:22 (73.246.23.72)
Are you aware there is a MAJOR tube shortage occurring right now? The supply of power tubes - especially 6550s and KT88s - is very thin. New Sensor (the Sovtek importer/distributor and owner of the Sa .......
15: Vintage Asylum, RE: Thanks (0.00)
Posted by Jim McShane on 2023-02-14, 13:06:58 (73.246.23.72)
Also - if the amp still has the original selenium rectifier be sure to replace it with a fast/quiet diode. .......
16: Vintage Asylum, RE: Anode Follower VS Cathode Follower Hiss Madness (0.00)
Posted by Jim McShane on 2023-02-13, 19:39:57 (73.246.23.72)
I didn't intend to get involved in this discussion - but there seems to be a lot of confusion and a lot of blame heaped on the anode/plate follower - which in and of itself is NOT the cause of the his .......
17: Tubes Asylum, RE: Tube vendor recommendations (0.00)
Posted by Jim McShane on 2023-01-13, 18:56:21 (73.246.23.72)
You have mail as of about 3 hours ago. .......
18: Tubes Asylum, RE: Years ago there were images of the different KT90 versions. . (0.00)
Posted by Jim McShane on 2023-01-12, 13:36:47 (73.246.23.72)
Look at the link below. Don't worry about the "type IV" - it was just a change in the getter patch shape. They are identical to the type IIIs. .......
19: Tube DIY Asylum, RE: I straightened up today...Anyone remember... (0.00)
Posted by Jim McShane on 2022-12-15, 18:02:52 (73.246.23.72)
If those are K40s they are very good caps - I've used them in my capacitor kits for the Citation amps for as long as I could get them. But the supply has been diminished greatly in the values most oft .......
20: Tube DIY Asylum, RE: Citation V Progress (0.00)
Posted by Jim McShane on 2022-08-17, 08:33:46 (73.246.23.72)
While you are in there be sure to clean the pots really well and check them to ensure they are working properly. There's no easier time to do it. You did a nice job on the kit too - bravo! ::: TOPIC:: .......
21: Tube DIY Asylum, RE: Ping: Jim McShane - Citation V (0.00)
Posted by Jim McShane on 2022-08-12, 15:46:06 (73.246.23.72)
As Chip, has mentioned, the 1 Ohm resistors are there to lower the heater voltage to the 12BY7As (the Cit II does it with a single 2.2 Ohm resistor BTW) to reduce noise. I have never seen a Cit V with .......
22: Tube DIY Asylum, RE: HK Citation V Rebuild (0.00)
Posted by Jim McShane on 2022-07-30, 12:54:12 (73.246.23.72)
Question - what is the 33 uf 450 volt cap going to be used for? Also - if you think the power supply kit should include another terminal strip or two please let me know - I'm very grateful for the fee .......
23: Tube DIY Asylum, RE: 6L6GC screens in Heathkit W5m amps. (0.00)
Posted by Jim McShane on 2022-07-24, 21:04:59 (73.246.23.72)
Be sure to add a screen stopper at each of the output tubes. I use 274 Ohms but anything around there will work fine. I also add a CL-90 inrush limiter to the power trafo secondary red/white lead ahea .......
24: Tubes Asylum, RE: Jim McShane (0.00)
Posted by Jim McShane on 2022-06-05, 13:41:40 (73.246.23.72)
Be sure you check my website tubes page... There have been regular updates posted there. I'm still having some nasty Covid symptoms (congestion, extreme fatigue at times) and can't do too much work. .......
25: Vintage Asylum, RE: Sansui AU-70 int. tube amp., opinions?. (0.00)
Posted by Jim McShane on 2022-04-27, 14:20:04 (73.246.23.72)
The 2SB381 PNP Germanium transistors in the phono stage are often noisy and a VERY hard to source. So it may not be that much of a blessing .......
26: Tubes Asylum, RE: Citation II KT88 Tube Matching (0.00)
Posted by Jim McShane on 2022-04-25, 18:26:40 (73.246.23.72)
18 Ohms is the value i recommend for use with KT-88 Genalex reissue tubes. I've sent an email to the amp owner so we'll get him all squared away ASAP. .......
27: Tubes Asylum, RE: JJ Tubes (0.00)
Posted by Jim McShane on 2022-03-07, 14:25:55 (73.246.23.72)
Thanks a lot! Much appreciated... .......
28: Tubes Asylum, RE: JJ Tubes (0.00)
Posted by Jim McShane on 2022-03-07, 13:22:08 (73.246.23.72)
I replied to your previous post because I thought that you had raised a point that merited a response, and a point that I needed to clarify. For the record - there's some of "that Russian stuff" that .......
29: Tubes Asylum, RE: JJ Tubes (0.00)
Posted by Jim McShane on 2022-03-07, 12:07:16 (73.246.23.72)
Just to be clear, I am not "latched on" to my opinion. I have brought JJs into stock from time to time to see if things had improved. I used to sell a lot of JJ tubes - I still carry the EL84 and ECC9 .......
30: Tubes Asylum, RE: Tube making countries (0.00)
Posted by Jim McShane on 2022-03-03, 11:40:19 (73.246.23.72)
The Shuguang plant is closed. .......
31: Tubes Asylum, RE: Jim McShane Status (0.00)
Posted by Jim McShane on 2022-02-28, 12:12:35 (73.246.23.72)
Just so you know - I got SIXTY ONE emails requesting tubes today (2/28). There's no way I can get through all of those even in a week. And my ink jet document printer failed an hour ago... ::: TOPIC .......
32: Tubes Asylum, RE: Jim McShane Status (0.00)
Posted by Jim McShane on 2022-02-27, 17:32:47 (73.246.23.72)
Here's the story: 1. I have a notice posted on my web site tube page that says I can be a couple days behind answering emails. I am virtually ALWAYS behind now. I have 3 chronic health issues that wil .......
33: Tube DIY Asylum, RE: Strange distortion on one frequency from MkIIIs with older VTA board (0.00)
Posted by Jim McShane on 2022-01-31, 20:08:35 (73.246.23.102)
I seriously doubt the KT-90s are the cause. There is no incompatibility between a KT-90 Ei and a KT-88 with the possible exception of a type I KT-90 needing a bit less negative voltage to bias them co .......
34: Tubes Asylum, RE: that looks like a New Sensor label (0.00)
Posted by Jim McShane on 2022-01-28, 06:20:03 (73.246.23.102)
Just to clarify - Mike Mathews and his company (New Sensor) did not take over any tube factories except the Xpo-Pul plant in Saratov, Russia. What he did do was buy up the names/naming rights from a n .......
35: Tube DIY Asylum, RE: Thomas stereo organ amplifier 6973 to 6cz5 conversion (0.00)
Posted by Jim McShane on 2022-01-17, 18:51:17 (73.246.23.102)
FYI - I (and other vendors) stock the Electro-Harmonix 6973 which is still in production. I've had some good comments from people that use it - although it is certainly not a high volume selling tube. .......
36: Tubes Asylum, RE: Issue with tube bias drift in my integrated amplifier! (0.00)
Posted by Jim McShane on 2021-12-06, 14:03:49 (73.246.23.102)
As others have mentioned it could be line voltage variations which cause the change in bias voltage applied to the tube grids - which means the current through the tube will change. But here's a coupl .......
37: Tubes Asylum, RE: Total NOOB bias Question (0.00)
Posted by Jim McShane on 2021-10-30, 10:59:32 (73.246.23.102)
Take a look at item #6 in my FAQ post. That may help you to understand it. .......
38: Tubes Asylum, RE: What do these numbers mean? (0.00)
Posted by Jim McShane on 2021-10-22, 14:51:19 (73.246.23.102)
One additional thing to know - you can convert the TV-7 meter reading number to transconductance with some simple multiplication. All you do is read the meter and multiply it by a number based on th .......
39: Tubes Asylum, RE: That would have been illegal (0.00)
Posted by Jim McShane on 2021-09-16, 14:15:50 (73.246.23.102)
I was replying to Triode_Kingdom in general/overall terms, not specifically about the tubes in this case. .......
40: Tubes Asylum, RE: That would have been illegal (0.00)
Posted by Jim McShane on 2021-09-16, 12:33:04 (73.246.23.102)
It was VERY common in the last years of the big tube makers to have "inaccurate" countries of origin.. FWIW - those appear to me to be SED/winged C 6550Cs. Earlier production SEDs were fine quality tu .......
41: Tubes Asylum, RE: Jim McShane is always my first choice for buying tubes (0.00)
Posted by Jim McShane on 2021-07-23, 12:34:04 (73.246.23.102)
You guys are a tough crowd! Hee!! .......
42: Tubes Asylum, RE: KT88 Tubes Better than Gold Lions? (0.00)
Posted by Jim McShane on 2021-06-26, 08:03:02 (73.246.23.102)
Nunki wrote about the EH KT-88: "that EH performs a bit on the clean and "cool" side but delivers an astonishing precise bass quality" That is exactly how I would describe it as well. .......
43: Tubes Asylum, RE: KT88 Tubes Better than Gold Lions? (0.00)
Posted by Jim McShane on 2021-06-21, 12:12:13 (73.246.23.102)
"Better" is a term only you can define for yourself. I think the GLs are superb - and they are very reliable. It seems your opinion and mine differ... But it appears you are looking for a tube that ha .......
44: Tube DIY Asylum, RE: Volume pot recommendation (0.00)
Posted by Jim McShane on 2021-05-29, 14:15:16 (73.246.23.102)
That may have been a defective unit. My experience has been quite positive with their stuff. .......
45: Tubes Asylum, RE: How important is tube matching? (0.00)
Posted by Jim McShane on 2021-05-14, 08:35:17 (73.246.23.102)
If you were replacing a dual triode preamp tube and had a choice between one with closely matched currents but transconductance readings that were significantly different, And the other choice was on .......
46: Tubes Asylum, RE: How important is tube matching? (0.00)
Posted by Jim McShane on 2021-05-13, 15:57:27 (73.246.23.102)
To answer you have to define what you mean by "more important". Mismatched transconductance will not cause damage to the tube(s) or the amp. So if your objective is to operate the tube safely and with .......
47: Tubes Asylum, RE: How important is tube matching? (0.00)
Posted by Jim McShane on 2021-05-12, 17:12:25 (73.246.23.102)
Is matching performed on the Ip rating or some other factors? If you read my FAQ post you'll find the answer to that and more. Click on the FAQ link at the top of the page. Check out item #6 for mor .......
48: Tubes Asylum, RE: How important is tube matching? (0.00)
Posted by Jim McShane on 2021-05-12, 15:57:15 (73.246.23.102)
The problem is that the single bias adjustment is for all six of the tubes. So unless all six tubes are matched you'll be unable to set the bias properly on all the tubes since at any given bias point .......
49: Tube DIY Asylum, RE: HK Citation V (0.00)
Posted by Jim McShane on 2021-04-29, 14:56:35 (73.246.23.102)
That's exactly the reason on both the Citation II and Citation V. .......
50: Tubes Asylum, RE: On Jim's site? (0.00)
Posted by Jim McShane on 2021-04-13, 18:47:09 (73.246.23.102)
With most browsers you can just hit CTRL-F and the search box appears at the bottom of the screen. then just type in the search term you want. That's it! .......
51: Tubes Asylum, RE: First KT-66 Unboxing. Where's my Pin 6? (0.00)
Posted by Jim McShane on 2021-03-28, 19:28:28 (73.246.23.102)
You don't mean you were using the TUBE pin 6 for a tie point, do you? You weren't soldering to the tube pin itself, correct? Don't you mean you were using the tube SOCKET pin 6 for the tie point conne .......
52: Vintage Asylum, RE: Please heed Mr. McShane's advice below. (0.00)
Posted by Jim McShane on 2021-03-22, 17:52:40 (73.246.23.102)
Essentially... As it stands right now, your 299C can only use quad sets of 7591A tubes that are matched for cathode current. And if you need to replace the power tubes - unless the tube quad you purch .......
53: Vintage Asylum, RE: Please heed Mr. McShane's advice below. (0.00)
Posted by Jim McShane on 2021-03-22, 16:10:30 (73.246.23.102)
My schematic for the 299C shows (2) DC balance pots and (0) AC balance pots. But the later models do seem to have AC pots. That's all I know. (Referring to the picture he posted) His unit has two pots .......
54: Vintage Asylum, RE: Please heed Mr. McShane's advice below. (0.00)
Posted by Jim McShane on 2021-03-21, 17:49:22 (73.246.23.102)
What I posted still goes. The AC balance pots have essentially no effect on bias current. Their presence is irrelevant to the bias current situation. The AC pots perform a different function in the ci .......
55: Vintage Asylum, RE: Please heed Mr. McShane's advice below. (0.00)
Posted by Jim McShane on 2021-03-21, 16:11:30 (73.246.23.102)
Your 299C has bias BALANCE (a.k.a. DC balance) pots. They can only equalize the current of the two tubes in a given channel. They CANNOT allow you to adjust the overall bias voltage to get the current .......
56: Vintage Asylum, RE: You have a few choices. (0.00)
Posted by Jim McShane on 2021-03-18, 07:50:27 (73.246.23.102)
Pin 6 of the output tubes should be at. -18.5V. Be careful! That is a common but potentially risky misconception. As I wrote in my FAQ: "Keep one last thing in mind - often you see a voltage "spec" .......
57: Tubes Asylum, RE: Best new tube for ARC Classic 150? (0.00)
Posted by Jim McShane on 2021-03-04, 12:00:39 (73.246.23.102)
I don't recommend the Tung-Sol 6550s. I don't even stock them right now as they are having issues with excessively high bias currents. .......
58: Tubes Asylum, RE: Best new tube for ARC Classic 150? (0.00)
Posted by Jim McShane on 2021-03-03, 19:37:25 (73.246.23.102)
I would suggest the Sovtek 6550WE - I tend to want to retube ARC gear with the same tubes they use/recommend. It often makes life easier for the amp's owner if they ever have to deal with ARC regardin .......
59: Tubes Asylum, RE: Best new tube for ARC Classic 150? (0.00)
Posted by Jim McShane on 2021-03-03, 19:23:08 (73.246.23.102)
Your statement that "only "tuby" sound likers like GL KT88" is far from a universally held opinion. In fact, in my experience it is a rarely heard description of the tube's performance. If that is you .......
60: Tubes Asylum, RE: Best new tube for ARC Classic 150? (0.00)
Posted by Jim McShane on 2021-03-03, 10:05:04 (73.246.23.102)
Just FWIW - I sell quite a few of the Sovtek 6550WEs, but almost none go into guitar amp service that I know of. I find the 6550WE does an excellent job, and I have VERY few problems with them other t .......
61: Tubes Asylum, RE: Jim McShane (0.00)
Posted by Jim McShane on 2021-02-07, 10:21:28 (73.246.23.102)
I received your note - but I'm more than 4 days behind on some stuff so I'll get back to you as quick as I can. .......
62: Tubes Asylum, RE: Jim McShane (0.00)
Posted by Jim McShane on 2021-02-03, 12:59:14 (73.246.23.102)
You wrote - "When it rains, it pours...." SO true. Yesterday we lost power for almost the entire morning which just added to the fun. My whole day was shot as a result. .......
63: Tubes Asylum, RE: Jim McShane (0.00)
Posted by Jim McShane on 2021-02-02, 09:20:26 (73.246.23.102)
Here's what is going on... I've posted some of this on my website but nobody seems to have seen it - so I'm posting part of an email that I recently sent to a customer who asked how I was doing. It's .......
64: Tube DIY Asylum, RE: Fixed bias (0.00)
Posted by Jim McShane on 2021-01-25, 14:52:47 (73.246.23.102)
Just FYI - you might want to check out my FAQ post. Item #4 deals with your question - and there are some other useful items in their as well. .......
65: Tubes Asylum, RE: +1 (0.00)
Posted by Jim McShane on 2021-01-17, 17:01:15 (73.246.23.102)
The GL KT-88s are my most reliable power tube - I reject well under 1% of them. However, the factory matching is terrible, just so you know... Check out my FAQ for some helpful info: .......
66: Tubes Asylum, RE: Svetlana 6550 Identificiation (0.00)
Posted by Jim McShane on 2021-01-16, 15:30:52 (73.246.23.102)
The "square" holes were only present on the 6550C version. The earlier 6550B and others had small round holes in the plate. The "square" holes were made to allow a screen alignment tool to be used at .......
67: Tubes Asylum, RE: That's not the kind of source (0.00)
Posted by Jim McShane on 2021-01-11, 12:08:14 (73.246.23.102)
Just so you know - the "factory" matching is really not very good. .......
68: Tube DIY Asylum, RE: "the K40s were fine" (0.00)
Posted by Jim McShane on 2020-11-22, 12:09:36 (73.246.23.102)
To confirm what you just said - I have never had a K40 failure, and I've handled thousands of them. If I sold some to anyone who had a failure they've never told me about it. I DO operate them within .......
69: Tube DIY Asylum, RE: Don't know if this is helpful... (0.00)
Posted by Jim McShane on 2020-11-15, 18:32:30 (73.246.23.102)
Carbon film resistors are also inductive - it's carbon composition resistors that are non-inductive. Carbon comps have some other drawbacks however. .......
70: Tubes Asylum, RE: Can someone tell me if 7058 tubes will work in my phono stage? (0.00)
Posted by Jim McShane on 2020-11-01, 18:48:37 (73.246.23.102)
No - many of the "7058" etched RCA tubes are really 12AX7s. The only way to know for sure is to verify how he heater is wired. .......
71: Tubes Asylum, RE: Can someone tell me if 7058 tubes will work in my phono stage? (0.00)
Posted by Jim McShane on 2020-10-31, 11:23:37 (73.246.23.102)
Also be aware that MANY RCA 7058s are actually just relabeled 12AX7s. So until you check the tube to verify the heater configuration you won't know for sure what you really have. .......
72: Tube DIY Asylum, RE: Why do that? The fumes from over heated paint would be nasty. nt (0.00)
Posted by Jim McShane on 2020-10-18, 15:11:29 (24.12.169.184)
What paint are you talking about? .......
73: Tube DIY Asylum, RE: Rustoleum Painter's Touch - any experience using it for amps? (0.00)
Posted by Jim McShane on 2020-10-17, 11:42:08 (24.12.169.184)
Just a thought - consider using automotive touch up paints. They are available in a WIDE variety of colors, are VERY durable, and have plenty of flexibility so they withstand metal expansion and contr .......
74: Tubes Asylum, RE: Help me identify this tube (0.00)
Posted by Jim McShane on 2020-10-13, 11:26:12 (24.12.169.184)
The 7226 and 6909 are production date codes - they stand for 26th week of 1972 and 9th week of 1969. the 274 is the EIA code for RCA tubes. It looks like a full wave rectifier as Steve mentioned, but .......
75: Vintage Asylum, RE: I've got a Heathkit AR-29 and need some parts for MPX board (0.00)
Posted by Jim McShane on 2020-10-05, 12:26:45 (24.12.169.184)
Their only relationship is that they are all distributors/sellers of electronic parts. They are competitors, along with Allied and Arrow and some other smaller firms. .......
76: Vintage Asylum, RE: I've got a Heathkit AR-29 and need some parts for MPX board (0.00)
Posted by Jim McShane on 2020-10-03, 15:33:54 (24.12.169.184)
Just FYI - Mouser is owned by Warren Buffett - it's a Berkshire-Hathaway company. And Digi-Key is a privately held company. The information above is sourced from Dun & Bradstreet. Finally, Newark Elec .......
77: Tubes Asylum, RE: Help Identifying 12AX7 tubes (0.00)
Posted by Jim McShane on 2020-09-23, 11:50:38 (24.12.169.184)
I wouldn't have told you it was a Tung-Sol unless I was sure it was a Tung-Sol! Also 322 is the EIA code for Tung-Sol. Finally the getter shape is typical of early production Tung-Sols. Later tubes ha .......
78: Tubes Asylum, RE: Help Identifying 12AX7 tubes (0.00)
Posted by Jim McShane on 2020-09-22, 17:11:01 (24.12.169.184)
It looks like a Tung-Sol 12AX7. The heavy numbering and the line above the elongated octagon are Tung-Sol markings. .......
79: Tube DIY Asylum, RE: Best .22 ufd (450V-650V) coupling cap... (0.00)
Posted by Jim McShane on 2020-09-10, 13:22:09 (24.12.169.184)
They only had 630 volt rated up to .1 uf values. You could get .22 or .47 in 400 volts though. .......
80: Tube DIY Asylum, RE: Best .22 ufd (450V-650V) coupling cap... (0.00)
Posted by Jim McShane on 2020-09-10, 13:19:35 (24.12.169.184)
Just FYI - Auricaps are not film & foil construction - they are metallized polypropylene. .......
81: Tubes Asylum, The Genalex reissue U77/GZ34 (nt) (0.00)
Posted by Jim McShane on 2020-08-15, 14:03:47 (24.12.169.184)
.......
82: Tubes Asylum, RE: Best current production sub for Amperex/Mullard GZ34? (0.00)
Posted by Jim McShane on 2020-08-14, 14:58:06 (24.12.169.184)
They are NOT the same tube. They are significantly more durable for one thing. They also are quite well constructed. I've also noticed that the voltage drop is VERY consistent from tube to tube and fr .......
83: Vintage Asylum, RE: Harmon Kardon Citation-II (0.00)
Posted by Jim McShane on 2020-07-29, 18:50:40 (24.12.169.184)
Just to clarify - the Ei tubes I carried were KT-90, not KT-99. IIRC KT-99s were Chinese made copies of the Ei tubes. And yes, the type II KT-90 Eis are simply GREAT tubes!! I wish Ei was still in bus .......
84: Tubes Asylum, RE: since your asking (0.00)
Posted by Jim McShane on 2020-07-29, 18:38:45 (24.12.169.184)
Just to clarify... 1. Although I am a sponsor here and have been for a long time I do not have a sponsor page. 2. Mike Mathews' company New Sensor (based in New York) owns the Saratov, Russia tube pla .......
85: Tubes Asylum, RE: Whistling Tube Question (0.00)
Posted by Jim McShane on 2020-06-27, 17:25:28 (24.12.169.184)
Clean the tube socket well. Look at the FAQ below for more info. .......
86: Vintage Asylum, RE: Make Sure It Endures (0.00)
Posted by Jim McShane on 2020-06-07, 12:25:19 (24.12.169.184)
You have your opinion, that's fine. But your opinion is not held by all - nor should it be. I've personally replaced innumerable caps that either show signs of distress or no longer are even close to .......
87: Tube DIY Asylum, RE: SN63 (0.00)
Posted by Jim McShane on 2020-06-04, 17:44:55 (24.12.169.184)
I would add Qualitek to the list of quality solders. .......
88: Tube DIY Asylum, RE: Glad it worked... and a warning (0.00)
Posted by Jim McShane on 2020-05-28, 11:48:43 (24.12.169.184)
The Cit II does not use PC boards so that's not an issue here. .......
89: Tube DIY Asylum, RE: Dynaco dying.... (0.00)
Posted by Jim McShane on 2020-05-09, 14:00:52 (24.12.169.184)
Hi Rod! The Sovtek 5AR4 is not a good choice for a Dyna - they are simply not up to the task. The Tung-Sol 5AR4 or Genalex U77/GZ34 reissues are much better tubes. I'd use one of those new production .......
90: Vintage Asylum, RE: GE Stereo Classic amp & tuner... (0.00)
Posted by Jim McShane on 2020-04-29, 13:11:13 (24.12.169.184)
Just FYI - the 6973 is in production now. The 6973 EH is readily available in both singles and matched sets. .......
91: Tubes Asylum, RE: Sylvania ----RE: Who Made These Older 6l6 Groove Tubes (0.00)
Posted by Jim McShane on 2020-04-23, 12:05:53 (24.12.169.184)
Tubemonger is correct as he is virtually always. BTW - if they were GEs the tube number would be etched into the tube glass along with a dot pattern. .......
92: Tubes Asylum, RE: Audio Research VT60 tube amp biasing question (0.00)
Posted by Jim McShane on 2020-03-31, 16:39:21 (24.12.169.184)
5 mv isn't a big deal - 5 mv voltage across a 10 Ohm resistor is half a milliamp of current. And it wouldn't take much of an AC line voltage change for that to occur. I'm personally doing okay so far .......
93: Tubes Asylum, RE: Audio Research VT60 tube amp biasing question (0.00)
Posted by Jim McShane on 2020-03-31, 12:42:13 (24.12.169.184)
What Al said!! This is important - line voltage variations are common and definitely affect bias in most gear. And unfortunately it is often overlooked as a cause of "drifting" bias. .......
94: Tubes Asylum, Thank You Ralph! nt (0.00)
Posted by Jim McShane on 2020-01-14, 16:44:36 (24.12.169.184)
.......
95: Tubes Asylum, RE: Does anyone know if Jim McShane is okay? (0.00)
Posted by Jim McShane on 2020-01-13, 16:49:47 (24.12.169.184)
I'm still here. I am definitely battling some health issues but I'm able to work about 3 hours a day. So I'm a bit slower than I used to be but I'm still at it! I checked my emails again and I didn't .......
96: Tubes Asylum, RE: 6p14p-ev or EL84M will both be affordable and work well. nt (0.00)
Posted by Jim McShane on 2020-01-13, 10:08:46 (24.12.169.184)
Just FYI - the EL-84M Sovtek is the current production of the 6P14P-EV. It is a very fine tube. .......
97: Tube DIY Asylum, RE: Cap suggestion for Sherwood S-5000 (0.00)
Posted by Jim McShane on 2019-12-20, 11:30:02 (24.12.169.184)
If the cap is indeed a Solen I can't think of any reason to chage it. It's a fairly recent addition to the amp I'd expect and I sincerely doubt it'll make any difference if you change it. If you just .......
98: Tubes Asylum, RE: Brief review of Gold Lion 12AU7 (0.00)
Posted by Jim McShane on 2019-12-02, 16:18:24 (24.12.169.184)
I've had them since early 2012... .......
99: Tubes Asylum, RE: EL-509 lights up the room (almost) (0.00)
Posted by Jim McShane on 2019-12-02, 16:14:31 (24.12.169.184)
Humble suggestion - check my FAQ post. It'll cover a lot of ground for you. .......
100: Vintage Asylum, RE: And he/she is??? (0.00)
Posted by Jim McShane on 2019-11-25, 09:27:38 (24.12.169.184)
Right now Chris is VERY busy - that's why I haven't posted the info on my website. But if things ease up a bit I'll have it posted on my site. I did have a second tech lined up but unfortunately he r .......
101: Vintage Asylum, RE: YES YES YES (0.00)
Posted by Jim McShane on 2019-11-22, 15:22:47 (24.12.169.184)
I have a different (and superb!) tech now. Don Sachs no longer does any vintage gear work at all. .......
102: Tubes Asylum, RE: As I recall.... (0.00)
Posted by Jim McShane on 2019-11-19, 14:02:06 (24.12.169.184)
That is partially correct. I think it might have been socket to pin contact issues but I couldn't be sure. All I know is there were a number of cases where the plain pin EH 12BH7 did not perform prope .......
103: Tubes Asylum, RE: Has anyone tried the new Gold Lion 12AU7 (0.00)
Posted by Jim McShane on 2019-11-12, 12:41:01 (24.12.169.184)
Hi Charles! I did get your email - it arrived last Saturday. As I wrote you in reply to your email, I'm sorry I can't reply faster. I saw your post in this thread and I wanted to tell you that due to .......
104: Tubes Asylum, RE: Has anyone tried the new Gold Lion 12AU7 (0.00)
Posted by Jim McShane on 2019-11-11, 15:27:10 (24.12.169.184)
I've found them to be very reliable and quite nice sounding. I know Sondek doesn't agree (and of course that's okay!) but I just want people to know that there are a lot of folks out there who do use .......
105: Tubes Asylum, RE: Disastrous tube rolling (0.00)
Posted by Jim McShane on 2019-10-16, 14:45:45 (24.12.169.184)
You almost certainly have poor contact between the tube pins and the tube sockets. Look at the FAQ for this forum (link below) Check out item #1 in the FAQ. That's what you need to do. .......
106: Vintage Asylum, RE: HK Cit II "The Deuce" or Mac 275 ? (0.00)
Posted by Jim McShane on 2019-10-15, 10:47:53 (24.12.169.184)
A lot depends on whether the amps (especially the 55+ year old Cit II) have been restored and/or updated. .......
107: Tubes Asylum, RE: A failure in a tube I've yet to see till now (0.00)
Posted by Jim McShane on 2019-10-11, 10:42:16 (24.12.169.184)
It does happen on rare occasion - both on some old stock and on VERY few new production tubes too. The spot weld was weak and somewhere in the handling/shipping process the ring broke away from the su .......
108: Tubes Asylum, RE: Looking for a laid back 12ax7 (0.00)
Posted by Jim McShane on 2019-09-10, 13:59:34 (24.12.169.184)
+1 on the Genalex B759/12AX7 reissues. .......
109: Tubes Asylum, RE: Simple Question Setting for... (0.00)
Posted by Jim McShane on 2019-08-29, 15:29:54 (24.12.169.184)
You might not have it - I have a couple TV-7s (a B and a D) and the 6550 isn't listed in those books either! .......
110: Tubes Asylum, RE: Simple Question Setting for... (0.00)
Posted by Jim McShane on 2019-08-29, 09:21:45 (24.12.169.184)
Use the 6550 settings if you have them. It seems like Hickok could never get both the 6550 and KT-88 listings into any of their tube test datasheets. .......
111: Tube DIY Asylum, RE: Me too, thanks Jim! (0.00)
Posted by Jim McShane on 2019-08-28, 15:06:25 (24.12.169.184)
I'm glad I could help TK, and thanks for your kind thoughts too! .......
112: Tube DIY Asylum, RE: Really tight tube sockets.......Lube or ? ........ (0.00)
Posted by Jim McShane on 2019-08-27, 13:30:08 (24.12.169.184)
Use a little DeOxit on the pins before you insert the tube into the socket. It will ease things somewhat and won't inhibit good contact. There's nothing wrong with the Beltons - they are excellent qua .......
113: Tube DIY Asylum, RE: Anyone heard from Jim McShane Lately? (0.00)
Posted by Jim McShane on 2019-08-26, 15:32:03 (24.12.169.184)
Hi Rich! No sir, you are welcome to share that. In fact I appreciate you sharing the news so people don't think I'm just ignoring them. I have to take FIVE different blood pressure meds - some 2 or 3 .......
114: Tube DIY Asylum, RE: Anyone heard from Jim McShane Lately? (0.00)
Posted by Jim McShane on 2019-08-26, 15:19:44 (24.12.169.184)
I had a medical appointment earlier today. But I'm back and I sent you a reply around Noon today so it should be in your inbox.. .......
115: Amp/Preamp Asylum, RE: Solid State - Tube scale (0.00)
Posted by Jim McShane on 2019-08-18, 16:02:01 (24.12.169.184)
A properly redone Citation II is FAR from bloated!! Any "bloat" would have to come from some other part of the system. .......
116: Vintage Asylum, RE: I would do the diode mod... (0.00)
Posted by Jim McShane on 2019-08-13, 11:37:47 (24.12.169.184)
Installed in the primary the thermistor would have little or no impact IMHO. I'm with Eli - add it to pin 8 if you want to add one. .......
117: Vintage Asylum, RE: Seek, and ye shall find (0.00)
Posted by Jim McShane on 2019-08-12, 12:32:25 (24.12.169.184)
Just to clarify one thing... The new Tung-Sol and Genalex are indeed quite reliable. But there are some amps - like some of Bob Latino's VTA amps for instance - that run the 5AR4s right at their limit .......
118: Tube DIY Asylum, RE: First fitting of the final components (0.00)
Posted by Jim McShane on 2019-08-08, 15:07:33 (24.12.169.184)
Hee! I can only recall selling two output transformers - and they came from a bunch of stuff that I had gotten hold of - not a working or rebuildable amp. I could never have recalled who I sold them .......
119: Tube DIY Asylum, RE: First fitting of the final components (0.00)
Posted by Jim McShane on 2019-08-08, 13:21:05 (24.12.169.184)
It sounds/looks like a great project - I just hope that a Citation II didn't have to die for you to build it. .......
120: Tubes Asylum, RE: Grrr!!! It's the power transformer (0.00)
Posted by Jim McShane on 2019-08-08, 13:18:59 (24.12.169.184)
Check with Heyboer in Grand Haven MI. They can likely fix you up. .......
121: Tubes Asylum, RE: I have a whole bunch of AB that have been kept really dry. . . (0.00)
Posted by Jim McShane on 2019-08-02, 11:11:27 (24.12.169.184)
I have to make a couple points here: a) The grid stopper values that are suitable for a triode grid stopper are significantly different than what you can use on a tube with a screen. The Miller capaci .......
122: Tubes Asylum, RE: Are there any best or better carbon comp. . . (0.00)
Posted by Jim McShane on 2019-08-02, 10:56:27 (24.12.169.184)
I've found the Kamaya and Xicon resistors work just fine and they are cheap. You can spend $0.75 or so and use Ohmites. But honestly - as long as the resistor is properly made it'll work fine. Sometim .......
123: Tubes Asylum, RE: Why carbon comp and not carbon film? (0.00)
Posted by Jim McShane on 2019-08-01, 17:30:16 (24.12.169.184)
Carbon comps have the lowest inductance. It's not a matter of what material the resistive element is made of - it's a matter of how the resistor is physically constructed. Carbon composition resistor .......
124: Tubes Asylum, RE: With the signal going through the grid stopper. . . (0.00)
Posted by Jim McShane on 2019-07-31, 15:38:19 (24.12.169.184)
John - the key element is the low inductance the carbon comps offer. IMHO you can spend a whole lot more money - but you won't get better performance than with a decent 50 cent carbon composition resi .......
125: Tubes Asylum, RE: Randall Aiken's post on stoppers (0.00)
Posted by Jim McShane on 2019-07-31, 12:35:36 (24.12.169.184)
Be careful here- the grid resistor has much more efect in an amp where the grid is driven positive. Steve's advice (and Randall Aiken's if you followed the link) is not 100% applicable to audio amps w .......
126: Tube DIY Asylum, RE: Loud whistle upon power up, that went away ............ (0.00)
Posted by Jim McShane on 2019-07-07, 10:54:38 (24.12.169.184)
Bedfore you do anything else do some tube socket maintenance. Clean the sockets well and retension them if needed. Then see what happens. The link below has some useful info on cleaning. .......
127: Tubes Asylum, RE: After 25 years of production use... (0.00)
Posted by Jim McShane on 2019-06-28, 16:26:16 (24.12.169.184)
Belton sockets use wrap-around terminal contacts made of tin plated phosphor bronze (note this is the same material that was used by Cinch) and the insulating material is fiberglass filled polyphenyle .......
128: Tube DIY Asylum, RE: Popping started again in my VTA-120. (0.00)
Posted by Jim McShane on 2019-05-30, 09:48:21 (24.12.169.184)
Is the ringing from both channels or just one? If it's just one channel making noise you can swap the KT-88s from the quiet channel to the other to see if the noise moves with the swap. If it doesn't .......
129: Tubes Asylum, RE: Chirp/squeak when shutting down amp (0.00)
Posted by Jim McShane on 2019-05-28, 10:47:09 (24.12.169.184)
You might look at my FAQ post here... Item #1 is the most critical .......
130: Tubes Asylum, RE: Ei 12AX7 (0.00)
Posted by Jim McShane on 2019-05-21, 13:09:31 (24.12.169.184)
Do be aware that the late production Eis (mid 90s or so) tend to be microphonic. The BEST of the Eis were the earlier ones which were often relabeled by GE, Telefunken, National, and others. ::: TOPIC .......
131: Tube DIY Asylum, RE: It's Wishful thinking (0.00)
Posted by Jim McShane on 2019-05-17, 14:12:50 (24.12.169.184)
First off - diode voltage drops occur even if they are installed in a DC circuit. Second - I've heard that power supply - and it is VERY good powering that circuit. Third - since the El-Cheapo was go .......
132: Tube DIY Asylum, RE: Jim, think the bias supply portion is the same. (0.00)
Posted by Jim McShane on 2019-05-13, 11:08:25 (24.12.169.184)
There's a number of differences in component values (resistors, filter capacitor) between the two versions. .......
133: Tube DIY Asylum, RE: Here's a schemo of that part of the circuit. (0.00)
Posted by Jim McShane on 2019-05-11, 11:37:10 (24.12.169.184)
I think this is a 500C schematic excerpt, not an 800C. DAK - if you need an 800C manual and schematic drop me a note and I'll email a copy to you. If you have the unit serial number that will help. :: .......
134: Tube DIY Asylum, RE: Enclosed transformers are usually potted (0.00)
Posted by Jim McShane on 2019-04-24, 17:02:56 (24.12.169.184)
Here's a quote from the Citation II manual: "The Citation II power transformer is potted with a chemical compound called "PERMAFIL" which is specifically selected because of its high heat conductivit .......
135: Tube DIY Asylum, RE: No paint is permanent on stainless (0.00)
Posted by Jim McShane on 2019-03-29, 11:53:43 (24.12.169.184)
You could powder coat them - SS powder coats just fine. .......
136: Tubes Asylum, RE: The KT-88 (0.00)
Posted by Jim McShane on 2019-03-28, 06:02:45 (24.12.169.184)
When reading FenderLover's post keep in mind he's approaching this from a guitar player/guitar amp perspective. That's not a criticism or a fault of Steve's by any means - it's just that he is judging .......
137: Tubes Asylum, RE: It's not scientific but (0.00)
Posted by Jim McShane on 2019-03-27, 15:01:37 (24.12.169.184)
Don't fall for the retubing advice? In other words I can't be trusted to offer advice because I have a "D" after my name on this forum? How do you know that I can't be trusted? Have you or someone .......
138: Tubes Asylum, RE: Quicksilver KT88 mono amps (0.00)
Posted by Jim McShane on 2019-03-27, 11:12:33 (24.12.169.184)
You are, of course, entitled to your opinion. But that doesn't mean your opinion is the only opinion of value. There are some new production tubes that are BETTER THAN the old stock. There are some ol .......
139: Tubes Asylum, RE: Quicksilver KT88 mono amps (0.00)
Posted by Jim McShane on 2019-03-27, 10:00:15 (24.12.169.184)
I don't carry the new Mullards so I can't really comment on them. But I'd sure be tempted to try the Genalex reissues if it was my amp. They are really good tubes. Many (including our comrade Mike Sam .......
140: Tubes Asylum, RE: Quicksilver KT88 mono amps (0.00)
Posted by Jim McShane on 2019-03-26, 17:17:33 (24.12.169.184)
The 5AR4 is a GE, the 12FQ7 is a Sylvania, and the KT-88 picture doesn't come up - only an error message. The GE and the Sylvania are both very good tubes. .......
141: Tubes Asylum, RE: Quicksilver KT88 mono amps (0.00)
Posted by Jim McShane on 2019-03-26, 09:23:18 (24.12.169.184)
What brand of power and small signal tubes are you using? There is a significant range of tonal balance in the KT-88s depending on brand and the same often goes for the small tubes. Maybe a tube chang .......
142: Tubes Asylum, RE: How about TJ KT88/C (CNE) tubes ? (0.00)
Posted by Jim McShane on 2019-03-24, 11:18:23 (24.12.169.184)
Your post is one of the reasons there is really no substitute for actually listening to the tubes in YOUR system, in YOUR room, with YOUR electronics, through YOUR speakers - and most importantly, wit .......
143: Tube DIY Asylum, RE: grid stoppers (0.00)
Posted by Jim McShane on 2019-03-08, 09:57:38 (24.12.169.184)
I prefer to use carbon composition (CC) resistors as grid stoppers, as they have essentially zero inductance (just a tiny bit of lead and stray inductance). The drawbacks to carbon comps really don't .......
144: Tubes Asylum, RE: Maybe an RFT ecc83? (0.00)
Posted by Jim McShane on 2019-03-03, 13:12:22 (24.12.169.184)
It's hard to see in the pic he posted. But if they are RFT they could be "real". RFT was authorized to produce tubes for Telefunken for a time near the end of West German tube production. .......
145: Tubes Asylum, RE: FAKE ? GE 6550 (0.00)
Posted by Jim McShane on 2019-03-03, 13:10:00 (24.12.169.184)
That's REALLY interesting! Somebody went through a lot of trouble to make those and they did pretty well. The lettering on the box is off just a bit; the print on the tube is just a bit too low on the .......
146: Tubes Asylum, RE: Question about tube pins (0.00)
Posted by Jim McShane on 2019-03-01, 15:15:26 (24.12.169.184)
Wanna bet? .......
147: Tubes Asylum, RE: Question about tube pins (0.00)
Posted by Jim McShane on 2019-02-28, 15:29:58 (24.12.169.184)
"Keep the tube in an upright position with pins pointing downward as one does not want to have solder flow into the tube." I'm not sure exactly what you meant but solder CAN'T flow into the tube. The .......
148: Tubes Asylum, RE: That is normal (0.00)
Posted by Jim McShane on 2019-02-27, 15:11:11 (24.12.169.184)
Keep in mind you want to be sure that not only the tubes are fully warmed - but all the components in the amp are as well! Resistors, caps, etc., do change value some with temperature. So doing your f .......
149: Tubes Asylum, RE: How do they compare (0.00)
Posted by Jim McShane on 2019-02-15, 17:42:54 (24.12.169.184)
It's hard to say exactly because tubes sound different in different amps and to different people. But I'd say the LPS is quite well balanced in tone and some of the old stock had some emphasis at one .......
150: Tubes Asylum, RE: Hi Jim, when my Sovtek 12AX7s die, are the spiral filament Sovtex LPs worth it when I have DC heaters?valves (0.00)
Posted by Jim McShane on 2019-02-14, 08:56:49 (24.12.169.184)
Yes - they are very inexpensive and they are tonally ideal (IMHO) for a phono stage. .......
151: Tubes Asylum, RE: Sovtek 12ax7lps (0.00)
Posted by Jim McShane on 2019-02-13, 11:56:38 (24.12.169.184)
They are VERY good tubes, I agree. And the filament is nearly completely covered by the cathode sleeve. In a dark room you can see a little bit of light at the top of the internal structure but that's .......
152: Tubes Asylum, RE: I bet those 6106 would be nice in my . . (0.00)
Posted by Jim McShane on 2019-02-06, 13:34:27 (24.12.169.184)
Actually I tried a 6106 in my TV-7B tester some years back. It didn't work well at all - I had to go back to a plain old 5Y3 then all was good again. Edited to fix typo - as usual... .......
153: Tubes Asylum, RE: Overall i like the 6l6 and 6l6g (0.00)
Posted by Jim McShane on 2019-01-29, 13:34:10 (24.12.169.184)
The new Tung-Sol 6L6G CAN be used in a 6L6GC application. The "guts" of the G bottle tubes are the same as the 6L6GC. .......
154: Tube DIY Asylum, RE: Not at my house it's not... (0.00)
Posted by Jim McShane on 2019-01-29, 12:11:51 (24.12.169.184)
You are lucky - you may have a decent supply but other than tubes already in private hands there are damn few out there. Don't assume that because you have them that they are available to everybody. .......
155: Tubes Asylum, RE: Why ? (0.00)
Posted by Jim McShane on 2019-01-19, 17:10:44 (24.12.169.184)
A "huge gain" is not likely. But as I said - it depends on the circuit whether it makes any difference at all. In a follower or buffer circuit it is not likely to make any significant difference. In a .......
156: Tubes Asylum, RE: Why ? (0.00)
Posted by Jim McShane on 2019-01-19, 08:34:28 (24.12.169.184)
First off, there is no such tube as the 6GC7. The tube's correct number is 6CG7 (or 6FQ7). The 6CG7/6FQ7 has lower distortion than the 12AU7 - which can improve tone in some circuits. If the 12AU7 is .......
157: Tube DIY Asylum, RE: Staking Tools (0.00)
Posted by Jim McShane on 2019-01-08, 14:29:03 (24.12.169.184)
Well, then don't do business with them. Sheesh, I was just trying to help. Sorry... .......
158: Tube DIY Asylum, RE: Staking Tools (0.00)
Posted by Jim McShane on 2019-01-08, 10:45:29 (24.12.169.184)
Mouser puts a disclaimer under the picture of the 1715 you must have missed: "Images are for reference only See Product Specifications " So disregard that image - the datasheet image is the correct o .......
159: Tubes Asylum, RE: NOS 6189 and 12AT7 choices (0.00)
Posted by Jim McShane on 2018-12-26, 09:48:59 (24.12.169.184)
If it was my preamp I'd get Mulard CV4024s for the 12AT7 sockets and I wouldn't even bother with NOS 6189/12AU7s. The current production Genalex reissue B749/12AU7 is a really fine tube - and IME they .......
160: Tubes Asylum, RE: recommended source for Gm values for "new" tubes (0.00)
Posted by Jim McShane on 2018-12-14, 12:40:49 (24.12.169.184)
But there are large variances in Gm of new tubes. These are perfectly normal variances - not problems. So one tube would be a far too small sample size to determine a representative Gm value unfortuna .......
161: Tube DIY Asylum, RE: Outgassing is not necessarily a vacuum problem (0.00)
Posted by Jim McShane on 2018-12-13, 11:13:56 (24.12.169.184)
There is sometimes a specification for maximum bulb temperature on tubes - power tubes especially. This spec is usually 200 to 250 C which is 392 to 482 F. That's a LONG ways away from halogen bulb .......
162: Tube DIY Asylum, RE: Outgassing is not necessarily a vacuum problem (0.00)
Posted by Jim McShane on 2018-12-12, 15:44:59 (24.12.169.184)
I read your post regarding vacuum pumping and I really appreciate you sharing that. However I take issue with this line: "IMO, vacuum tubes should NEVER be handled bare handed and if touched, cleaned .......
163: Tube DIY Asylum, RE: Look at this pic, it appears more localized (0.00)
Posted by Jim McShane on 2018-12-09, 12:48:18 (24.12.169.184)
The gasses present are not being ionized. Stray electrons striking the tube glass causes impurities in the glass to fluoresce. That's what causes the glow. BTW - NO tube has a perfect vacuum - not cur .......
164: Vintage Asylum, RE: Okay, thanks! (0.00)
Posted by Jim McShane on 2018-12-08, 14:07:05 (24.12.169.184)
As I posted before - the MRA series Mills are non-inductive Ayrton-Perry wound resistors. So it's unlikely that they would cause any instability. I see no problem with using the Mills in that position .......
165: Tube DIY Asylum, RE: Looking For a Transformer Rewinder (0.00)
Posted by Jim McShane on 2018-12-08, 14:00:08 (24.12.169.184)
Thank you for that info! .......
166: Tube DIY Asylum, Looking For a Transformer Rewinder (0.00)
Posted by Jim McShane on 2018-12-05, 17:35:37 (24.12.169.184)
Help! The gent who used to rewind transformers for me has retired. Gary Brown is no longer doing any winding at all - he's fully retired. He used to do power and output trafos but now I have no one to .......
167: Vintage Asylum, RE: Screen resistors (0.00)
Posted by Jim McShane on 2018-12-04, 14:52:26 (24.12.169.184)
The MRA series Mills are Ayrton-Perry wound non-inductive resistors. .......
168: Tubes Asylum, RE: Which 6CA7 or EL34? (0.00)
Posted by Jim McShane on 2018-12-03, 09:12:28 (24.12.169.184)
Yes! If the plate voltage (meanimg the difference between the voltage at the plate and the voltage at the cathode) is 450 volts for instance, then a single tube has to dissipate 75 ma (.075 amps) x 45 .......
169: Tubes Asylum, RE: Which 6CA7 or EL34? (0.00)
Posted by Jim McShane on 2018-12-02, 14:40:36 (24.12.169.184)
Hi Steve, If the KT-77 Genalex fits in your budget then that's the tube of choice. It is the best of the EL34 "family" of tubes out there IMHO. FYI, there are biasing issues with the 6CA7 EH right now .......
170: Tube DIY Asylum, RE: Agree and... (0.00)
Posted by Jim McShane on 2018-11-05, 14:28:26 (24.12.169.184)
Thank you TK - the respect is mutual. .......
171: Tube DIY Asylum, RE: Agree and... (0.00)
Posted by Jim McShane on 2018-11-05, 12:03:14 (24.12.169.184)
Since I am the only other person that posted replies in this thread you must be referring to me. It was NOT a subjective opinion I was expressing - I've MEASURED peak power wattage from a number of Ci .......
172: Tube DIY Asylum, RE: Also... (0.00)
Posted by Jim McShane on 2018-11-02, 15:07:24 (24.12.169.184)
The secondary of the Cit II power trafo is rated at 1.7 AMPS on its B+ winding. It'll provide plenty of energy to meet the needs of the amp when producing its rated 60 watts per channel - and it'll do .......
173: Tube DIY Asylum, RE: Also... (0.00)
Posted by Jim McShane on 2018-11-02, 09:27:58 (24.12.169.184)
I would just add two comments: 1. The brand name on the cap can be counterfeited easily. I would say that the safest bet is to purchase from vendors who guarantee the authenticity of the parts they se .......
174: Tube DIY Asylum, RE: I'd get "real" 6L6GC tubes (0.00)
Posted by Jim McShane on 2018-10-23, 09:45:17 (24.12.169.184)
The Tung-Sol 6L6GC-STR reissues are a fine choice, as Steve mentioned. .......
175: Tubes Asylum, RE: Power tubes (0.00)
Posted by Jim McShane on 2018-10-18, 14:42:35 (24.12.169.184)
Very good tubes, those Genalex U77/GZ34s! .......
176: Tubes Asylum, RE: Interesting. (0.00)
Posted by Jim McShane on 2018-10-18, 09:44:14 (24.12.169.184)
I'm not Eli, but I agree regarding the poor quality of the older Russian/Chinese "coke bottle" 5U4Gs. On the other hand the 5U4GB EH has proven to be a very good tube with excellent quality. As well, .......
177: Tubes Asylum, RE: I have not heard of that tube before my radar too. (0.00)
Posted by Jim McShane on 2018-10-13, 15:27:51 (24.12.169.184)
Actually he still has some left - I believe he sold a lot of them. He tooled up and made a base for them so they could plug into a 9 pin socket - so the flying leads weren't a problem. If you look on .......
178: Tube DIY Asylum, RE: Thanks for the tip. (0.00)
Posted by Jim McShane on 2018-09-29, 08:47:44 (24.12.169.184)
Buy one extra socket and remove the pins from it to install in the pin 2 spot. Problem solved! .......
179: Tube DIY Asylum, RE: Citation V Arrived (0.00)
Posted by Jim McShane on 2018-09-25, 08:47:47 (24.12.169.184)
The exchange of the 270 Ohm dropping resistor in the power supply for the choke is a significant improvement. The screen supply benefits greatly from this change. Plan on adding screen stoppers too. H .......
180: Tube DIY Asylum, RE: Citation V Arrived (0.00)
Posted by Jim McShane on 2018-09-24, 14:19:56 (24.12.169.184)
"The "siliconized" bias supply produces about -62.5V (schematics show -54V)." Between the change to a diode and the higher line voltage that sounds about right. Yes, the increase in output tube bias .......
181: Tubes Asylum, RE: Can a 6L6G be substituted for a 6L6GC ? (0.00)
Posted by Jim McShane on 2018-09-18, 11:25:12 (24.12.169.184)
There is an exception to the rule Eli mentions. The current production 6L6G "coke bottle" Tung-Sol uses the 6L6GC guts so it CAN be used to replace a 6L6GC. The old stock tube are NOT suitable subs in .......
182: Tube DIY Asylum, RE: Screen Voltage (0.00)
Posted by Jim McShane on 2018-09-14, 13:18:21 (24.12.169.184)
With a top shelf power supply, the reduced bias current, and today's higher AC line voltages it's not too unusual to see 475 volt B+ and 460 volts on the screen. .......
183: Tube DIY Asylum, RE: PS Caps (0.00)
Posted by Jim McShane on 2018-09-13, 19:15:55 (24.12.169.184)
My power supply stuff won't fit on Sheldon's board. Below are some pics of my Cit V power supply (with a couple extras on it, I'm building for a good friend). Note there are still some resistors and w .......
184: Tube DIY Asylum, RE: Citation V Q. (0.00)
Posted by Jim McShane on 2018-09-13, 10:57:35 (24.12.169.184)
Hi TK, A couple tube thoughts first... The 6P3S-E would be pushed pretty hard in the Cit V - especially with the stock bias circuit which lets the tubes get run real hot/hard. The tube I recommend for .......
185: Tubes Asylum, RE: One bad tube in a quad, what to do? (0.00)
Posted by Jim McShane on 2018-09-10, 12:56:37 (24.12.169.184)
Check out my FAQ post for more info on tube pin/socket cleaning. Eli is right on the money. .......
186: Amp/Preamp Asylum, RE: Self Healing Capacitors. Have you heard of this? (0.00)
Posted by Jim McShane on 2018-09-07, 10:42:19 (24.12.169.184)
Certain capacitor types have always been self-healing. It is inherent in how they are constructed. Essentially a short inside the cap burns itself open in the area of the short which "heals" the cap. .......
187: Tubes Asylum, RE: New production (0.00)
Posted by Jim McShane on 2018-08-22, 10:30:42 (24.12.169.184)
Your amp may be able to use the 7581As as well as the EL34s - but a 7581A is a derivative of the 6L6 family. So they are only direct subs for the 6CA7 in amps that were designed to take either tube. T .......
188: Tubes Asylum, RE: Jim, what makes the yellow-green glow in magic-eye valves? (0.00)
Posted by Jim McShane on 2018-08-13, 13:56:42 (24.12.169.184)
Hi Tim! Briefly - the eye tubes use a fluorescent coating on their target that glows when energized. Here's a great site about "magic eye" tubes (link below)... I know some eye tubes were made in Russ .......
189: Tubes Asylum, RE: I Miss the Blue Glow (0.00)
Posted by Jim McShane on 2018-08-10, 13:46:21 (24.12.169.184)
Different levels of glass impurities and also the different number of stray electrons hitting a given area of the glass (which can depend both on the physical structure of the tube internals and the s .......
190: Tubes Asylum, RE: I Miss the Blue Glow (0.00)
Posted by Jim McShane on 2018-08-09, 15:14:11 (24.12.169.184)
I'm sorry, that is not correct. Oxygen is only one of the gasses absorbed by getters. Here is an excerpt from the intro to "Barium Getter and Residual Gases in Electronic Tubes" published in 1960 In .......
191: Tubes Asylum, RE: I Miss the Blue Glow (0.00)
Posted by Jim McShane on 2018-08-09, 10:49:02 (24.12.169.184)
Guys - it's not a vacuum issue! The blue glow inside the tube's glass envelope (like is seen in DAK's picture) is caused by electrons striking the glass. Impurities in the glass are what fluoresce. If .......
192: Tubes Asylum, RE: Customer service, here's how it's done (0.00)
Posted by Jim McShane on 2018-08-05, 12:19:57 (24.12.169.184)
Thank you all for the very kind words - and all your support! .......
193: Vintage Asylum, RE: update: shipping to foreign countries (0.00)
Posted by Jim McShane on 2018-07-25, 15:13:08 (24.12.169.184)
Just FYI - I find the USPS does just fine tracking overseas packages - to most countries anyway. They do an excellent job at a fraction of the price of UPS or DHL. .......
194: Vintage Asylum, RE: sherwood 5500-II line stage question (0.00)
Posted by Jim McShane on 2018-07-24, 09:02:13 (24.12.169.184)
Bill wrote "If you want to use the Sherwood as a power amp, it should be a fairly simple mod to set up one input pair as a direct input to the power amp section, bypassing the selector switch, volume .......
195: Vintage Asylum, RE: sherwood 5500-II line stage question (0.00)
Posted by Jim McShane on 2018-07-22, 09:07:12 (24.12.169.184)
Half of each of the 12AX7s downstream of the volume control and just ahead of the 7868s are used as voltage amps if that is what you are asking. .......
196: Tubes Asylum, RE: 6L6GC to KT66 (0.00)
Posted by Jim McShane on 2018-07-13, 13:23:17 (24.12.169.184)
Really as long as you have adequate heater current capacity and you can bias the tube to the current you desire it's pretty much a drop in. The "spec" OPT primary number is just a guide - and the guid .......
197: Tubes Asylum, RE: You using Reflector 6H23P-EB? (0.00)
Posted by Jim McShane on 2018-07-10, 13:44:36 (24.12.169.184)
Again, just to remind everyone - the current 6H23P-EB is sold as the EH 6922. I can't recall if any RAM tubes are sourced from the Saratov plant though. .......
198: Tubes Asylum, RE: Are there different EH6922? (0.00)
Posted by Jim McShane on 2018-07-10, 10:47:23 (24.12.169.184)
No, there are no other EH tubes - although I'm certain the quality of the screening/testing does vary from vendor to vendor. But under most circumstances they are quite durable. In your case the Genal .......
199: Tubes Asylum, RE: I have to agree (0.00)
Posted by Jim McShane on 2018-07-09, 17:07:36 (24.12.169.184)
Eli, I think you are confusing these with the Genalex N709/EL84s which I don't warranty at over 12 watts dissipation. The Genalex 6922 is solid. Maybe not as tough as the EH (what is?) but certainly .......
200: Tubes Asylum, RE: No way to know. (0.00)
Posted by Jim McShane on 2018-07-09, 15:25:44 (24.12.169.184)
It won't shorten tube life if you measure tube life in operating hours. A given tube operating under given conditions will function for some number of operating hours. But measured with a calendar it .......
201: Tubes Asylum, RE: Thanks, y'all. I ended up getting the Genelecs. (0.00)
Posted by Jim McShane on 2018-07-09, 10:55:00 (24.12.169.184)
I hope those Genalexes were well screened for low noise - otherwise you may still have hiss. In my experience the RM gear requires VERY low noise tubes. .......
202: Tube DIY Asylum, RE: 100 power amplifiers to lift your hat (0.00)
Posted by Jim McShane on 2018-07-07, 11:53:01 (24.12.169.184)
I started to read that list sometime back. Naturally I looked to see if the Citation amps (especially the Cit II) were listed. The "Deuce" is listed, but from the description of the amp the author wro .......
203: Tubes Asylum, RE: Is the 12BH7 a better choice than the 5687? (0.00)
Posted by Jim McShane on 2018-06-26, 13:10:47 (24.12.169.184)
True, the old stock is hard to find. But I've had excellent results with the EH. And it is readily available. .......
204: Vintage Asylum, RE: AR3 woofers (0.00)
Posted by Jim McShane on 2018-06-12, 16:05:16 (24.12.169.184)
Here's another Edgar Villchur video you should check out .......
205: Vintage Asylum, RE: AR3 woofers (0.00)
Posted by Jim McShane on 2018-06-12, 15:55:34 (24.12.169.184)
It WAS high fidelity - but AR/Edgar Villchur always said his/their design goal was to project even levels of power into the entire room - not just the "sweet spot" on axis. That caused a lot of opinio .......
206: Tubes Asylum, RE: New Genalex KT88's (0.00)
Posted by Jim McShane on 2018-06-10, 14:00:25 (24.12.169.184)
I appreciate not only your very kind words - but your comments about the KT-88 Genalex reissue as well. They are a VERY fine tube - not meaning "very fine as compared to other current production tube .......
207: Tubes Asylum, RE: Genalex Golden Lion 5ar4/gz34 reissue failure? (0.00)
Posted by Jim McShane on 2018-06-01, 16:58:00 (24.12.169.184)
Clean the rectifier tube socket and the tube pins well - retension the socket contacts if need be. It may well be that simple. .......
208: Tube DIY Asylum, RE: Well, now that you've explained his logic (0.00)
Posted by Jim McShane on 2018-05-24, 09:40:35 (24.12.169.184)
I'm not defending or condemning his approach. All I'm saying is that what he describes is done frequently - especially in cases where the person doing the work is familiar with how the unit he's worki .......
209: Tube DIY Asylum, RE: A voltmeter is your friend (0.00)
Posted by Jim McShane on 2018-05-23, 12:05:14 (24.12.169.184)
His reason for turning the amp on is to warm the tubes enough so they will conduct AFTER the power is turned off which drains the capacitors. And even though using a meter to check is safer many an ex .......
210: Tubes Asylum, RE: "....and you only need one" (0.00)
Posted by Jim McShane on 2018-05-23, 10:08:48 (24.12.169.184)
The V1 tube is shared between channels - one triode is used for each. I believe the middle tube on the PC bioard is V1 but you might want to confirm that. .......
211: Tubes Asylum, RE: Need a warm sounding tube for a ARC VT60 (0.00)
Posted by Jim McShane on 2018-05-22, 09:38:26 (24.12.169.184)
The 6550WE Sovtek is now one of the OEM tubes used by ARC, and it may be just what you are looking for. It has a bit of extra midrange warmth that is very pleasing. They are also very affordable - whi .......
212: Vintage Asylum, RE: Update on health. (0.00)
Posted by Jim McShane on 2018-05-15, 10:51:37 (24.12.169.184)
You make me feel like a very lucky guy Mike! I just have to contend with diabetes (no insulin needed, just pills and exercise/diet) and high blood pressure. Both of those have been in our family histo .......
213: Vintage Asylum, RE: Update on health. (0.00)
Posted by Jim McShane on 2018-05-14, 12:38:48 (24.12.169.184)
All the best to you Mikey. I hope everything works out GREAT for you. And get well soon - that's an ORDER!! .......
214: Tube DIY Asylum, RE: Q about Citation II Transformers (0.00)
Posted by Jim McShane on 2018-05-12, 14:33:19 (24.12.169.184)
I posted some info here before but it was deleted for reasons unknown to me. Anyway I wanted to pass along some info about rewinding the OPTS. I'd mentioned Mercury Magnetics in California as a possib .......
215: Tubes Asylum, RE: Umm.. (0.00)
Posted by Jim McShane on 2018-05-07, 14:11:01 (24.12.169.184)
The silicon diodes of the day were fragile and COSTLY! For instance, the "top hat" diodes in the Citation II were rated at 600 PIV (which wasn't high enough unless 2 diodes were used in series) and 50 .......
216: Tube DIY Asylum, RE: question re:testing tubes (0.00)
Posted by Jim McShane on 2018-04-23, 11:46:33 (24.12.169.184)
"I have found that even lower testing tubes can perform satisfactorily, though at a somewhat lower volumes." This is not true with most circuits. Circuits using negative feedback are not nearly as l .......
217: Tube DIY Asylum, RE: question re:testing tubes (0.00)
Posted by Jim McShane on 2018-04-23, 11:29:00 (24.12.169.184)
CB offers good advice! DO keep in mind that brand new tubes have large variances between them right out of the box. 2200 would not be unusual at all for a brand new tube, nor would 3000 be. Variances .......
218: Tube DIY Asylum, RE: Russian PIO Caps (0.00)
Posted by Jim McShane on 2018-04-14, 14:00:44 (24.12.169.184)
I don't understand what you mean - could you be more specific? .......
219: Tube DIY Asylum, RE: Russian PIO Caps (0.00)
Posted by Jim McShane on 2018-04-14, 11:17:59 (24.12.169.184)
What series of PIO caps are they? .......
220: Amp/Preamp Asylum, RE: Such issues don't exist (0.00)
Posted by Jim McShane on 2018-04-11, 11:14:12 (24.12.169.184)
To answer your questions... Do all Citation 2 amps undergo a complete transformation? No, many get partially done for a variety of reasons including cost (it ain't cheap!) and skill requirements for t .......
221: Amp/Preamp Asylum, RE: Such issues don't exist (0.00)
Posted by Jim McShane on 2018-04-10, 17:18:21 (24.12.169.184)
I'm not going to argue about your preference - but IMHO a properly redone Cit II will have been completely rebuilt electrically. 55 year old wire, etc. has to go and the same is true for the pa .......
222: Tube DIY Asylum, RE: Sockets Too Tight? (0.00)
Posted by Jim McShane on 2018-04-09, 12:47:11 (24.12.169.184)
Squirt a little DeOxit on the pins before inserting the tubes. It helps a bit. But they are TIGHT!! .......
223: Tubes Asylum, RE: So what's the deal with the JJ-7591S? (0.00)
Posted by Jim McShane on 2018-03-30, 10:21:26 (24.12.169.184)
Eli, Regarding the grid resistance issue you wrote: "IMO, a better solution to the resistance issue is switching from 12AX7s to 12DW7/7247s. The tube change will NOT correct the excessive grid circui .......
224: Vintage Asylum, RE: Citation II (0.00)
Posted by Jim McShane on 2018-03-18, 14:37:34 (24.12.169.184)
That ad smells very funny to me. First off it is not a Citation II anymore. The Citation II used video pentodes in the front end (12BY7As) not 6SN7 dual triodes. That was one of Stu Hegeman's signifi .......
225: Tubes Asylum, RE: Tubes for Unison's Simply Italy (0.00)
Posted by Jim McShane on 2018-03-09, 12:29:49 (24.12.169.184)
Don't overlook the Genalex B749/12AU7 reissues. They are VERY good. .......
226: Tubes Asylum, RE: Prima Luna Branded KT88 (0.00)
Posted by Jim McShane on 2018-03-06, 09:06:44 (24.12.169.184)
According to their website they use Genalex KT-88s now (at least in their Prologue 2): "KT88 Output Tubes. We use the current production copy of the legendary Genalex KT88. The tube sounds wonderful, .......
227: Tubes Asylum, RE: Tube glows on start up (0.00)
Posted by Jim McShane on 2018-02-03, 12:38:42 (24.12.169.184)
Follow the link below and read the FAQ post. It will help you on your noise issue. .......
228: Tubes Asylum, RE: Many European made signal tubes do this --- no worries. (0.00)
Posted by Jim McShane on 2018-02-03, 10:58:12 (24.12.169.184)
Your tubes are behaving completely normally. There is nothing worng with them. Some variation in the length and intensity of the flash at startup is also normal for a variety of reasons. Not all tube .......
229: Vintage Asylum, RE: Scott 340A with case, can I run it all day without issues? (0.00)
Posted by Jim McShane on 2018-01-31, 08:41:14 (24.12.169.184)
I wouldn't operate a power trafo at its maximum temp either since that likely would mean that under some operating conditions the unit could exceed the maximum. Consider that Citation II power trafos .......
230: Vintage Asylum, RE: Scott 340A with case, can I run it all day without issues? (0.00)
Posted by Jim McShane on 2018-01-30, 13:11:26 (24.12.169.184)
The temperature where most people can only keep their hand on a hot object is about 130 F. Even a cheapie power trafo is capable of operating very comfortably well above that temperature. For example, .......
231: Tube DIY Asylum, RE: Good place in the US or Canada to buy electronic pots for volume (0.00)
Posted by Jim McShane on 2018-01-21, 18:20:31 (24.12.169.184)
But be aware that if you want to use the stock knob then the PEC may not work. Many vintage units used a split/splined shaft. The PECs are not available with that shaft. So you'd have to work somethin .......
232: Tube DIY Asylum, RE: no power on Citation I - help please (0.00)
Posted by Jim McShane on 2018-01-21, 17:37:48 (24.12.169.184)
Check the fuse as has been mentioned. Replace it with the PROPER VALUE if needed. Then check for AC power at the power switch. The switch is not self-illuminated. There is a #1815 bulb that lights up .......
233: Tubes Asylum, RE: Think they are NOT dead... (0.00)
Posted by Jim McShane on 2018-01-21, 17:23:01 (24.12.169.184)
Steve is right. Those tubes could still have significant life left in them as the top getters are pretty much intact. The side getters are much smaller in area than the top getter so they tend to go a .......
234: Tubes Asylum, RE: KT88 Teslovak fake? (0.00)
Posted by Jim McShane on 2018-01-10, 07:38:10 (24.12.169.184)
I've never dealt with the Teslovaks so I'm really not qualified to say much, sorry! .......
235: Tubes Asylum, RE: KT88 Teslovak fake? (0.00)
Posted by Jim McShane on 2018-01-09, 16:59:37 (24.12.169.184)
There are a number of visible differences between the EH and the Genalex. The bases are different color, the Genalex has both a top and (2) side getters where the EH has only the top getter. There are .......
236: Tubes Asylum, RE: KT88 Teslovak fake? (0.00)
Posted by Jim McShane on 2018-01-09, 15:15:25 (24.12.169.184)
Regarding the Genalex KT-88... That is old news, and no longer relevant at all. The last update was in 2013 and much of the page has been the same since before 2009. The vast majority of people who ha .......
237: Tubes Asylum, RE: EL 34 quads without "burn in" is it necessary (0.00)
Posted by Jim McShane on 2018-01-07, 09:28:43 (24.12.169.184)
Wow, thank you for your vote of confidence! .......
238: Tubes Asylum, RE: EL 34 quads without "burn in" is it necessary (0.00)
Posted by Jim McShane on 2018-01-06, 14:37:41 (24.12.169.184)
Burn-in is done to stabilize the tube so the tube is likely to be more consistent and stable electrically when it gets to the user. This is of particular value in the case of matched tubes. It also he .......
239: Tube DIY Asylum, RE: but they all do (0.00)
Posted by Jim McShane on 2017-12-30, 21:43:11 (24.12.169.184)
Dennis wrote: "There are many, many ways to build a push-pull amplifier, The disadvantages musically are processing of the signal by trying to divide it into two pieces and then trying to re-assemble .......
240: Tube DIY Asylum, RE: Citation II cap panel (0.00)
Posted by Jim McShane on 2017-12-30, 15:59:02 (24.12.169.184)
I did see the post (obviously!) and I'll be happy to measure one for you if you'll drop me a note. I never had any of those made though. I think you are referring to the amp bottom/face plates that I .......
241: Vintage Asylum, RE: Sherwood S-5000 MK1 Power Transformer (0.00)
Posted by Jim McShane on 2017-12-29, 07:28:00 (24.12.169.184)
Understood. But I just wanted people to know that transformers CAN be successfully rewound. If that Sherwood has a trafo issue it CAN be solved - and if it's important the original trafo can go back o .......
242: Vintage Asylum, RE: Sherwood S-5000 MK1 Power Transformer (0.00)
Posted by Jim McShane on 2017-12-27, 09:40:21 (24.12.169.184)
Have you guys tried to have the power trafo rewound? I know Gary Brown rewinds Sherwoods. .......
243: Vintage Asylum, RE: Vinnie2, I agree with you..... But it depends on..... (0.00)
Posted by Jim McShane on 2017-12-20, 09:05:22 (24.12.169.184)
If you prefer euphonics and amps that act as "tone controls" then I agree that the Deuce is not the amp for you. But if you want HIGH FIDELITY (meaning faithful reproduction of the program material) .......
244: Vintage Asylum, RE: "why doesn't Mr Eli have one LOL".....Uh-oh... (0.00)
Posted by Jim McShane on 2017-12-19, 14:47:09 (24.12.169.184)
He does. I redid it for him some years ago. .......
245: Vintage Asylum, RE: Vinnie2, I agree with you..... But it depends on..... (0.00)
Posted by Jim McShane on 2017-12-19, 09:08:19 (24.12.169.184)
What Eli said! If you want to hear what program material went IN to the amp then coming OUT of the amp then I can't think of ANY amp as good. .......
246: Vintage Asylum, RE: Do I really need a Citation II? (0.00)
Posted by Jim McShane on 2017-12-14, 14:37:15 (24.12.169.184)
If you are sending the amp to Canada I'm assuming you'll be sending it to my colleague and ace bench tech Don Sachs. If it hasn't been properly redone he's the man to do it. The amp is simply amazing .......
247: Tubes Asylum, RE: Gold Lion KT77 vs EL34 (Svetlana or JJs) (0.00)
Posted by Jim McShane on 2017-12-14, 14:06:00 (24.12.169.184)
You are always the final judge - but I'd skip the EL34s. The KT-77 Genalex are REALLY good. What should you expect from the two EL34 brands you mentioned? IMHO - disappointment - if you expect either .......
248: Tubes Asylum, RE: Contact Jim McShane and explain your requirements. He will give you personal service. nt (0.00)
Posted by Jim McShane on 2017-12-13, 13:38:19 (24.12.169.184)
I posted my reply above just before you posted this note. I'd be happy to help him, but a) I can't afford to overstock so heavily to have enough tubes to choose from and b) it would likely take DAYS o .......
249: Tubes Asylum, RE: Genalex Gold Lion KT66 Help needed (0.00)
Posted by Jim McShane on 2017-12-13, 13:19:43 (24.12.169.184)
I'm sorry, but you are likely out of luck unless you want to pay BIG time for a lot of work. First, I'd have to find you an electrically properly matched quad - then of the electrically matched quads .......
250: Tube DIY Asylum, RE: How do you implement the LM117? NT. (0.00)
Posted by Jim McShane on 2017-12-08, 08:33:57 (24.12.169.184)
The LM117 is not what Eli referred to. He recommended the LM1117. Follow the link he posted for the data. The LM117 is the mil-spec version of the LM317 adjustable regulator. It is NOT a low dropuut d .......
251: Vintage Asylum, RE: Fisher 500C Maximum frequency reproduced (0.00)
Posted by Jim McShane on 2017-12-07, 11:50:56 (24.12.169.184)
The Cit II early transformers were +0, -1db from 2 to 80KHz at 1 watt output. The later model with the 450KHz resonant frequency was even better. Look at the H-K bulletin below: But back to the Fi .......
252: Tubes Asylum, RE: BTW, you seem to be knowledgeable of this problem so (0.00)
Posted by Jim McShane on 2017-11-24, 13:23:12 (24.12.169.184)
The VTA/Latino ST-120s and M-125s DO push the rectifiers hard and there the diode mod is a must as well as maintaining a line voltage that doesn't get up too high. But my experience with the VTA/Latin .......
253: Tubes Asylum, RE: 12FQ7 best recommendation for "QUIETNESS" (0.00)
Posted by Jim McShane on 2017-11-14, 14:30:03 (24.12.169.184)
Sure. Just be sure the heater is wired up properly to work with the 12BH7 - pins 4 and 5 should have the 12 volts and pin 9 should be empty. Pin 9 is not used on the 12FQ7 but it is the heater center .......
254: Tubes Asylum, RE: 12FQ7 best recommendation for "QUIETNESS" (0.00)
Posted by Jim McShane on 2017-11-14, 10:17:15 (24.12.169.184)
Yes - get tubes that are specifically tested for low noise performance. The supply of 12FQ7s is dwindling so this may not be as easy as a few years back... There is no one brand/maker you can point t .......
255: Tubes Asylum, RE: Red PLate Tube/Cary SLI 80 Question (0.00)
Posted by Jim McShane on 2017-11-11, 14:43:44 (24.12.169.184)
But DO clean them. What if the contact is intermittent?? If you own a tube amp you MUST be prepared to some some routine maintenance from time to time. It is in the best interests of both sound qual .......
256: Tubes Asylum, RE: Red PLate Tube/Cary SLI 80 Question (0.00)
Posted by Jim McShane on 2017-11-11, 12:47:48 (24.12.169.184)
You SHOULD clean the tube pins and sockets. It's entirely possible the tube rolling made poor contact a possibility. A loss of bias on that particular tube could be the cause. And if there is a contac .......
257: Vintage Asylum, RE: Okay thanks! Guess I'll stick to the OEM metal one. 8^) (n/t) (0.00)
Posted by Jim McShane on 2017-11-09, 10:08:11 (24.12.169.184)
FYI - if you tap either of the two parts of the AR platter separately they ring like a bell. Put them together on the table and they are stone dead! Not even the slightest hint of ringing is present. .......
258: Vintage Asylum, RE: Acrylic turntable platters (0.00)
Posted by Jim McShane on 2017-11-08, 09:43:33 (24.12.169.184)
I use a lead coated & balanced original AR 2 piece platter with a new spindle in my Merrill/AR-XA with the Merrill acrylic suspended sub-chassis. George Merrill now has gone to non-metallic platters o .......
259: Tubes Asylum, RE: Thank you (0.00)
Posted by Jim McShane on 2017-11-01, 16:59:26 (24.12.169.184)
I'm glad to help when I can! .......
260: Tubes Asylum, Tubes Asylum FAQ Update (0.00)
Posted by Jim McShane on 2017-11-01, 11:03:17 (24.12.169.184)
I just updated my Tubes Asylum FAQ post "Tube Problems" That Aren't Tube Problems to include an explanation of tube "glow" variation caused by the tube's heater. There are a couple pictures that may .......
261: Tubes Asylum, RE: dang, thought all this time 7581 A was tougher...25 watt dissipation?_nT (0.00)
Posted by Jim McShane on 2017-10-20, 12:43:44 (24.12.169.184)
Max dissipation on a 7581A is 35 watts. However that is rated using the Design Maximum rating system - so by the more commonly used Design Center ratings it would probably be closer to 30 watts. Whene .......
262: Tubes Asylum, RE: Any 6L6 tubes that are electrically equivalent to KT66? (0.00)
Posted by Jim McShane on 2017-10-19, 14:46:12 (24.12.169.184)
Do keep in mind that the heater current draw is .3 amps higher for a KT-66 vs. a 6L6GC or 7581A. .......
263: Vintage Asylum, RE: Scottky diode question (0.00)
Posted by Jim McShane on 2017-10-09, 15:06:25 (24.12.169.184)
PIV is the abbreviation for Peak Inverse Voltage - which is a way of saying the highest voltage the diode can withstand the in the "wrong" direction (reverse biased). Keep in mind that a diode sees a .......
264: Tubes Asylum, RE: Although Bob didn't mention it (0.00)
Posted by Jim McShane on 2017-10-09, 10:21:53 (24.12.169.184)
I believe Bob posted it in 2011(?). The idea goes back further though. Also, I recommend the UF series diodes, not the 1N series. Use UF4007 or UF5408 diodes for a bit lower noise. .......
265: Tubes Asylum, RE: Although Bob didn't mention it (0.00)
Posted by Jim McShane on 2017-10-09, 10:19:39 (24.12.169.184)
It's NOT just because the rectifiers are new production. Bob's amps work tube rectifiers pretty hard which means that ANY rectifier is more at risk than in amps that push them less hard. That's why he .......
266: Tubes Asylum, RE: Best 12AU7 (0.00)
Posted by Jim McShane on 2017-10-04, 16:17:42 (24.12.169.184)
That's really hard to say. But the feedback I've gotten says they are as good as whatever NOS the person was comparing them to. NOS is a bit too broad a category to be more specific in comparing I'm a .......
267: Tubes Asylum, RE: Best 12AU7 (0.00)
Posted by Jim McShane on 2017-10-02, 13:58:26 (24.12.169.184)
As Eli hinted at, the 12BH7 draws more heater current than the 12AU7. So the amp has to be able to supply that extra current without causing other issues. Many - but NOT ALL - can do it. .......
268: Tubes Asylum, RE: Best 12AU7 (0.00)
Posted by Jim McShane on 2017-10-02, 10:56:33 (24.12.169.184)
The B749/ECC82/12AU7 Genalex reissue is VERY good and not off the charts price wise. .......
269: Amp/Preamp Asylum, RE: New interconnect cable findings (0.00)
Posted by Jim McShane on 2017-09-16, 11:37:13 (24.12.169.184)
IIRC the RS cables are indeed higher capacitance than the Blue Jeans Cables. As a result there is apparently a softening of the top end that you've come to prefer. Cables are indeed a "tone control" i .......
270: Tubes Asylum, Wil do, thanks! (nt) (0.00)
Posted by Jim McShane on 2017-09-06, 13:09:03 (24.12.169.184)
.......
271: Amp/Preamp Asylum, RE: Kudos to Jim McShane - the EH-6922's really ARE the only tube for my AI Mod 3a (0.00)
Posted by Jim McShane on 2017-09-05, 08:22:19 (24.12.169.184)
FWIW - I have referred a number of people to our fellow Asylum inmate Wheezer when they had tube eating AI gear and he's been able to help them out. You might want to contact him if you have a c-j or .......
272: Amp/Preamp Asylum, RE: Kudos to Jim McShane - the EH-6922's really ARE the only tube for my AI Mod 3a (0.00)
Posted by Jim McShane on 2017-09-05, 08:14:38 (24.12.169.184)
The Genalex tubes are warmer toned than the EHs. The GLs are tonally closer to an old Amperex than to modern 6922s like the EH. The EH has an extended top end which is great if you need/like a bit mor .......
273: Tubes Asylum, RE: Simple (0.00)
Posted by Jim McShane on 2017-08-30, 08:54:18 (24.12.169.184)
He could also purchase a new PC board that uses available tubes and be done with the problem. The VTA 6SN7 board gets a lot of good press, you might check on that one. There are others as well. ::: TO .......
274: Vintage Asylum, RE: where does the SA-1000 fall in this comparison? nt (0.00)
Posted by Jim McShane on 2017-08-29, 14:28:59 (24.12.169.184)
But it was a very hard tube to manufacture! .......
275: Tube DIY Asylum, RE: It will certainly lead to failure (0.00)
Posted by Jim McShane on 2017-08-23, 09:28:57 (24.12.169.184)
Just FWIW - I've used 100s of K40 caps in Citation amps and many other vintage amps and had no trouble. I think Mike Samra would say the same thing. .......
276: Tube DIY Asylum, RE: Angela/Jensen copper foil in oil failure ... (0.00)
Posted by Jim McShane on 2017-08-23, 08:25:25 (24.12.169.184)
"IME, failed coupling caps load the grid with DC. But, do not cause massive current flow through the tube." But applying positive voltage to the grid will make the bias voltage less negative and that .......
277: Vintage Asylum, RE: Mac 275 vs HK Cit II (0.00)
Posted by Jim McShane on 2017-08-20, 11:06:53 (24.12.169.184)
You wrote: "Your mods witness the weaknesses of the original CII," I don't agree at all! I addressed opportunities presented by the much improved parts at my disposal versus what Stu Hegeman had. At .......
278: Vintage Asylum, RE: Mac 275 vs HK Cit II (0.00)
Posted by Jim McShane on 2017-08-19, 14:29:42 (24.12.169.184)
I've heard both, and here's my opinion: Best collectible - the Mac, no doubt about it. The Deuce isn't even close. Best sound - the (as Mike Samra calls them) "McShaned" Cit IIs. My friend and Grammy .......
279: Tubes Asylum, RE: New 6H30s malfunction after 300 hours? (0.00)
Posted by Jim McShane on 2017-08-18, 14:45:27 (24.12.169.184)
The amount of time the unit is on/operating over any given period of time is not irrelevant however. For instance if you use your unit 2 hours a day on average that's 730 hours a year. But leaving it .......
280: Tubes Asylum, RE: Jim McShane is the MAN! (0.00)
Posted by Jim McShane on 2017-08-16, 13:02:32 (24.12.169.184)
I REALLY appreciate that nice post, and I'm glad the ARC is working well now! Sometimes I think people believe I post about tube/tube socket cleaning just to avoid responsibility for problems that p .......
281: Tubes Asylum, RE: Good place to buy a PSVANE 12AX7? (0.00)
Posted by Jim McShane on 2017-08-15, 13:45:58 (24.12.169.184)
But there are also a lot of new production tubes that are superb! As well, there won't be NOS around forever in the numbers needed. Yes, there are examples of Chinese tubes that aren't so great. But .......
282: Vintage Asylum, RE: Michael, since you are familiar with the Sherwoods (0.00)
Posted by Jim McShane on 2017-08-13, 09:16:40 (24.12.169.184)
I'm not Mike, but that may be normal. What happens if you plug a tuner or some other line level device into the AUX input? The voltage output from the phone is not likely to be very high. If somethin .......
283: Tubes Asylum, RE: New 6H30s malfunction after 300 hours? (0.00)
Posted by Jim McShane on 2017-08-12, 07:46:11 (24.12.169.184)
You may not have had a tube problem - it may have been poor socket contact. Follow the link below to an FAQ post of mine for more info. FWIW, I have had little to no trouble with the 6H30Pi-EBs I've s .......
284: Tubes Asylum, Thank You For The Kind Words! (nt) (0.00)
Posted by Jim McShane on 2017-08-05, 13:03:03 (24.12.169.184)
.......
285: Tubes Asylum, RE: Reliability of KT150 a problem? (0.00)
Posted by Jim McShane on 2017-08-04, 10:21:35 (24.12.169.184)
I have sold a number of KT-150s (not large numbers, but a decent amount) and I have had near zero troubles with the tubes I sent out. Interestingly almost all have been sent overseas (Asia) so I was v .......
286: Tubes Asylum, RE: "It's best to run it a while on a test rig or ??" (0.00)
Posted by Jim McShane on 2017-08-04, 08:15:43 (24.12.169.184)
Running it with just the heater will help heat the tube so the getter can work to absorb gas; but it may not help if the cathode is poisoned. However - if the tube isn't gassy the chances of it runnin .......
287: Tubes Asylum, RE: Tubes need "re-burn in"? (0.00)
Posted by Jim McShane on 2017-08-03, 14:42:10 (24.12.169.184)
You and Lee are both on the right track... 1. Internal tube parts can continue to outgas while the tube is just sitting in storage. If the getter is in decent shape it can absorb the gas when the tube .......
288: Tube DIY Asylum, RE: Voltage regulator gas tube question (0.00)
Posted by Jim McShane on 2017-07-27, 11:35:20 (24.12.169.184)
The 0A2 and 0A2WA have similar tolerances. .......
289: Tubes Asylum, RE: Not quite as tuff as Mullard (0.00)
Posted by Jim McShane on 2017-07-26, 12:57:53 (24.12.169.184)
Well, Mullards certainly are fine tubes - but I don't like to generalize based on one experience. Suffice to say I'd have no qualms about using the JAN Philips in any socket designed for a 5AR4 since .......
290: Tube DIY Asylum, RE: Voltage regulator gas tube question (0.00)
Posted by Jim McShane on 2017-07-26, 11:18:58 (24.12.169.184)
No, it's not defective. The RCA tube manual states the 0A2 anode voltage drop can range from 140 volts to 168 volts. It's just normal variation from tube to tube. Also, the tube can take 20 minutes or .......
291: Tubes Asylum, RE: Mil spec Philips-ECG 5AR4 miss-labeled 5V4GA (0.00)
Posted by Jim McShane on 2017-07-26, 08:15:44 (24.12.169.184)
Steve, You wrote: "I've been using them for several years now (like 5 years). No problems." You won't have any problems! Why would you? As Steve O says these are real 5AR4s, full performance tubes. P .......
292: Tubes Asylum, RE: Tube amps and interconnects (0.00)
Posted by Jim McShane on 2017-07-01, 13:31:14 (24.12.169.184)
What Eli said! The Blue Jeans stuff is excellent at ANY price!! .......
293: Tubes Asylum, RE: 12au7 to 12bh7 (0.00)
Posted by Jim McShane on 2017-06-21, 15:02:42 (24.12.169.184)
-Lastly, measure the power transformer's temperatures before and after the installation of the 12BH7s. I'm not sure what the maximum rating would be (especially for your case), but from my understand .......
294: Tubes Asylum, RE: Why? (0.00)
Posted by Jim McShane on 2017-06-15, 11:33:19 (24.12.169.184)
What about tubes purchased in bulk? I've bought plenty of tubes packaged in egg-crate type boxes that were intended for use in production where individual boxes were both unnecessary and unwanted. Who .......
295: Tube DIY Asylum, RE: I don't doubt you can hear differences between 0 and 180 degrees (0.00)
Posted by Jim McShane on 2017-06-12, 09:16:13 (24.12.169.184)
That's an excellent post Lew! I would highly recommend you and other inmates take a look at the excerpt from an AES oral history from Edgar Villchur - the founder of Acoustic Research and driving forc .......
296: Tubes Asylum, RE: New development (0.00)
Posted by Jim McShane on 2017-06-08, 16:27:54 (24.12.169.184)
That definitely could be the case. I've had ONE case of the 6V6GTs acting up in all the years I've had them. And many have been used at 425 -450 volts. But it can happen... Hopefully the vendor will s .......
297: Tubes Asylum, RE: 450v plate and screen? (0.00)
Posted by Jim McShane on 2017-06-08, 14:21:23 (24.12.169.184)
Check the screen current and see what you find. That might be quite helpful. .......
298: Tubes Asylum, RE: 450v plate and screen? (0.00)
Posted by Jim McShane on 2017-06-08, 13:39:35 (24.12.169.184)
Is the 24 ma. plate current or cathode current(which includes both plate and screen current)? And what's the screen voltage on the amp? 4 or 5 ma. of screen current might push the total tube dissipati .......
299: Tubes Asylum, RE: Chinese GL 12AX7 (0.00)
Posted by Jim McShane on 2017-06-06, 13:28:06 (24.12.169.184)
I suspect that opinion is valid for guitar amps only. The Russian tube is quite warm in audio gear. Thanks for sharing it Steve. .......
300: Tubes Asylum, RE: Genalex Gold Lion Made in China (0.00)
Posted by Jim McShane on 2017-06-05, 10:16:41 (24.12.169.184)
That's been around for a few years. It's a New Sensor tube but made in China - not in their own Saratov plant. I've never heard it nor has anyone asked me/told me about it sonically so I can't tell yo .......
301: Tube DIY Asylum, RE: Questions about 6BG6G amp build (schematic) Grommes 216BA (0.00)
Posted by Jim McShane on 2017-05-23, 13:08:35 (24.12.169.184)
12FQ7s are getting quite scarce. It would be kind of you to let the guys who need them have first crack at them. Besides, the heater winding in the amp is a 6.3 volt winding - so a very minor rewirin .......
302: Vintage Asylum, RE: What cartridge to complete system; AR-XA, AR Integrated, AR3's (0.00)
Posted by Jim McShane on 2017-05-23, 08:03:24 (24.12.169.184)
My Uncle - Chuck McShane - was with AR back in the Cambridge Mass./Edgar Villchur days and was part of the R&D group with Roy Allison that developed the AR3a. Chuck always said that for the flattest r .......
303: Tube DIY Asylum, RE: Capacitor leak (0.00)
Posted by Jim McShane on 2017-05-12, 10:24:49 (24.12.169.184)
You are taking a chance by not replacing a suspect cap. Remember that these caps have a design life - and if it was an original cap it is close to 50 years old. That's WELL beyond the design life. So .......
304: Tubes Asylum, RE: OK I gotta ask. Why no more 6p3se / 6n3ce for sale other than on Ebay? (0.00)
Posted by Jim McShane on 2017-05-12, 08:10:59 (24.12.169.184)
Many (most?) of the 1970s and earlier production tubes were not made at Saratov. They were a slightly different tube. Were the tubes you compared Saratov made? The Foton and other 60s-70s vintage tube .......
305: Tubes Asylum, RE: OK I gotta ask. Why no more 6p3se / 6n3ce for sale other than on Ebay? (0.00)
Posted by Jim McShane on 2017-05-11, 12:50:32 (24.12.169.184)
Those tubes were old stock, produced in the old Soviet era. The supply has been heavily depleted so that's why I and some others no longer have them to offer. The remaining stock is being sold in smal .......
306: Tubes Asylum, RE: This is the part I don't understand. (0.00)
Posted by Jim McShane on 2017-04-28, 12:04:38 (24.12.169.184)
"I talked to Tomas at JJ and he was totally unaware of the bad tubes and he ran the whole factory." I wrote back and forth to him, and he denied any problems existed. He also said they had quality equ .......
307: Tubes Asylum, RE: I'm kind of completely turned off of JJ tubes now (0.00)
Posted by Jim McShane on 2017-04-27, 11:00:12 (24.12.169.184)
That's exactly my point - once the junk is weeded out as the end user you can often get a decent set of tubes - as you have found. But to have SO many failures in screening is simply too costly for ma .......
308: Tubes Asylum, RE: I'm kind of completely turned off of JJ tubes now (0.00)
Posted by Jim McShane on 2017-04-26, 10:43:05 (24.12.169.184)
That's not unusual either. The only 9 pin JJs I trust are the ECC99, the ECC832, and the EL84. .......
309: Tubes Asylum, RE: I'm kind of completely turned off of JJ tubes now (0.00)
Posted by Jim McShane on 2017-04-26, 08:23:49 (24.12.169.184)
Yes, what Eli said! The EL84 JJs are good. The octal tubes - not so much. For you guys who buy tubes from me and other good vendors - keep in mind that the good guys glean out the problem tubes before .......
310: Tube DIY Asylum, RE: Ping: Jim McShane (0.00)
Posted by Jim McShane on 2017-04-25, 09:00:43 (24.12.169.184)
Hi TK, Those are definitely not genuine GI diodes. The real Vishay General Instruments diodes have the part number including the GI characters - on the real ones they say "GI856" not just "856". The d .......
311: Tubes Asylum, RE: Tung Sol 6L6G (0.00)
Posted by Jim McShane on 2017-04-25, 08:47:12 (24.12.169.184)
You should have received my reply yesterday AM. You have mail I suspect! .......
312: Tubes Asylum, RE: Tung-Sol EL34B noise in PrimaLuna Dialogue HP Integrated (0.00)
Posted by Jim McShane on 2017-04-25, 08:26:13 (24.12.169.184)
Clean the sockets and tube pins well to ensure the tubes are making good contact with the tube pins. Look at my FAQ post (link below) for some good info on it. Don't cut corners - do a real thorough j .......
313: Tube DIY Asylum, RE: Photoflash Capacitors (0.00)
Posted by Jim McShane on 2017-04-24, 11:03:11 (24.12.169.184)
Chip, Thank you for finding and posting that! It is still 100% relevant today after 22 years. And BTW - when they pop it's a darn good "ear-ringing" bang!! I still use photoflashes (older stuff that g .......
314: Tubes Asylum, RE: Buy tubes from the right vendor that meets your needs because they do sound different. (0.00)
Posted by Jim McShane on 2017-04-24, 10:46:25 (24.12.169.184)
Wow, thank you so much for the kind words Mikey. I really appreciate it! .......
315: Tubes Asylum, RE: The other "G" types are excellent too! (0.00)
Posted by Jim McShane on 2017-04-21, 15:30:01 (24.12.169.184)
They are 19 watt dissipation too which is much less than the 6L6GCs. And the metal tube shell is connected to pin 1. So if the socket its plugged into uses pin 1 as a tie point - whatever voltage is .......
316: Tubes Asylum, RE: Tung Sol 6L6G (0.00)
Posted by Jim McShane on 2017-04-21, 13:48:18 (24.12.169.184)
If you do an Asylum search on Tung-Sol 6L6G you'll find a lot of info. The reaction was quite positive, especially by inmates Mike Samra and danlaudionut who both know their stuff. I like them a lot a .......
317: Tubes Asylum, RE: New Russian Tung Sol 6V6GT best sound? NOT (0.00)
Posted by Jim McShane on 2017-04-18, 10:02:43 (24.12.169.184)
It has been posted here many times by our old friend Poindexter that in his very highly developed push-pull amps (the "Musical Machine") he found the Tung-Sol reissue was the "best" tube. Many others .......
318: Vintage Asylum, RE: JJ dual section caps (0.00)
Posted by Jim McShane on 2017-04-07, 07:54:58 (24.12.169.184)
Maybe not. The large electrolytics were discontinued by Panasonic a year or two ago. Unless you find some in someones stock they're history I'm afraid. It's too bad since they were terrific caps, I ag .......
319: Tube DIY Asylum, RE: Cit II Doubler Filter (0.00)
Posted by Jim McShane on 2017-04-04, 13:02:13 (24.12.169.184)
Hi TK, Thanks for running the model! I know you didn't have all the best info to run it with either - so your effort was greatly appreciated. Just FYI - the DCR of the Cit II choke is 11 Ohms at room .......
320: Tube DIY Asylum, RE: Schottky (0.00)
Posted by Jim McShane on 2017-04-01, 10:46:27 (24.12.169.184)
My affection for that part is based on the excellent diode testing article done for Audio Amateur a number of years back. Rick Miller (who has excellent credentials but I can't recall them off hand) s .......
321: Tubes Asylum, RE: New Production tubes often fall outside factory specs (0.00)
Posted by Jim McShane on 2017-03-29, 08:01:45 (24.12.169.184)
That is not unusual even on old stock tubes. For example I have tested probably near 1000 NOS GE 6550As - a very fine tube - and cathode current varied by as much as 110%. Others would vary a bit more .......
322: Tubes Asylum, RE: EH 6V6GT or JJ 6V6s (0.00)
Posted by Jim McShane on 2017-03-26, 12:55:34 (24.12.169.184)
What Eli said - get the reissue Tung-Sols. .......
323: Tubes Asylum, RE: Driver tubes for Counterpoint SA 100 (0.00)
Posted by Jim McShane on 2017-03-10, 08:17:40 (24.12.169.184)
Don't rule out the Genalex reissue 6922s just because they aren't old stock. They are very good tubes, readily available, and have a warmer tone that is similar to some of the older Amperex/Mullard st .......
324: Tube DIY Asylum, RE: Magnetostriction distortion in audio transformers (0.00)
Posted by Jim McShane on 2017-03-07, 09:32:42 (24.12.169.184)
Thanks for the link, I need to study and digest this for sure. MUCH appreciated!! .......
325: Shady Lane, RE: Ripped off - Gary Brown, Stillewater, ME (0.00)
Posted by Jim McShane on 2017-03-02, 09:56:20 (24.12.169.184)
Have you spoken to Gary about this beyond an initial contact? I ask because I've done business with him and sent a lot of other people to him for transformer rewinds and had no serious trouble. Yes, h .......
326: Tubes Asylum, RE: You would really have to disagree with our production manager... (0.00)
Posted by Jim McShane on 2017-02-27, 12:09:58 (24.12.169.184)
It needs to be said that I am concerned with the parameters that allow the tube to perform properly in any given customer's gear. I do not test the tube's ability to meet unique characteristics impose .......
327: Tubes Asylum, RE: I wish I could agree with that (0.00)
Posted by Jim McShane on 2017-02-27, 11:20:54 (24.12.169.184)
We will have to disagree Victor - because I have had one reject in all the current tubes I've tested! Regardless, I do appreciate you sharing the information about your experience. Thank you sir... :: .......
328: Tubes Asylum, RE: What's the story on 6H30 tubes? (0.00)
Posted by Jim McShane on 2017-02-26, 14:32:36 (24.12.169.184)
I disagree with you Eli! I find the current production EB tubes to be excellent. I have seen many reviews where the listeners could not tell any difference between the tubes. The earlier EB versions w .......
329: Tubes Asylum, RE: 12av7 tubes (0.00)
Posted by Jim McShane on 2017-02-25, 08:19:05 (24.12.169.184)
Good thought - but no, these are BAD! And the reason I say 60 or so are bad is I haven't tested the rest yet. I fully expect that all will be microphonic. None are even close to usable. I got taken on .......
330: Tubes Asylum, RE: 12av7 tubes (0.00)
Posted by Jim McShane on 2017-02-24, 15:26:46 (24.12.169.184)
Just be sure they are checked for microphonics! I'm trying to dig up some right now for a customer - and I've had 60+ out of 100 NOS GEs turn up microphonic. I wouldn't have believed it if it didn't h .......
331: Tubes Asylum, RE: These are uber expensive (0.00)
Posted by Jim McShane on 2017-02-24, 08:07:42 (24.12.169.184)
After a lot of researching on my part I decided the EH Gold 2A3 was the tube. SE triodes are quite variable in how they are judged - it clearly is VERY system and listener dependent. The EH Gold seeme .......
332: Tube DIY Asylum, RE: Question... (0.00)
Posted by Jim McShane on 2017-02-17, 13:44:07 (24.12.169.184)
Ummm, I don't agree... The proper way to connect the outside foil is to the low impedance side of the circuit. That is (in the case of coupling caps) usually the plate of the prior stage. The grid .......
333: Tube DIY Asylum, RE: Here we go again. (0.00)
Posted by Jim McShane on 2017-02-17, 08:18:36 (24.12.169.184)
I have encountered no problems related to the metal shield/can at all Lew. I've soldered ground leads to the shell and listened to the caps with the shells both grounded and not grounded. I can't hear .......
334: Tube DIY Asylum, RE: Question... (0.00)
Posted by Jim McShane on 2017-02-17, 08:00:30 (24.12.169.184)
I should have said "metal" not steel. My bad. .......
335: Tube DIY Asylum, RE: Question... (0.00)
Posted by Jim McShane on 2017-02-17, 07:59:45 (24.12.169.184)
Okay - so you are assuming one lead goes to ground then, yes? .......
336: Tube DIY Asylum, RE: Here we go again. (0.00)
Posted by Jim McShane on 2017-02-16, 19:26:48 (24.12.169.184)
Hi Mikey, I can't speak to your reference to the SoniCaps (very little experience), but I totally agree with all that you posted about the Russian caps! You hit the price thing right on the head too - .......
337: Tube DIY Asylum, RE: Question... (0.00)
Posted by Jim McShane on 2017-02-16, 19:08:59 (24.12.169.184)
"If you are concerned about steel shell and leads of K72s, use FT or FCh types." Don't forget the FT series caps have steel shells as well. "One must thing with all Russian teflon caps is to electr .......
338: Tubes Asylum, RE: Tubes tested & burned in (0.00)
Posted by Jim McShane on 2017-02-16, 16:17:37 (24.12.169.184)
Well, it is interesting and of some importance to me what you say since reasoned debate often can clarify an issue - or at least encourage further thought. I'm genuinely sorry that you find it uninvo .......
339: Tubes Asylum, RE: Tubes tested & burned in (0.00)
Posted by Jim McShane on 2017-02-16, 15:50:15 (24.12.169.184)
You're grasping at straws IMHO. While any individual tube can't be changed once it's made, the overall quality of any production run of tubes is raised by eliminating tubes with issues. Why do you thi .......
340: Tubes Asylum, RE: Bias on Manley Snappers- your right (0.00)
Posted by Jim McShane on 2017-02-16, 14:35:33 (24.12.169.184)
Bob, The EH tubes out there these days tend to be hotter biasing. In fact it is difficult to get cool biasing EHs from the factory right now. So be careful that the tube vendor knows what he's selling .......
341: Tubes Asylum, RE: Bias on Manley Snappers (0.00)
Posted by Jim McShane on 2017-02-16, 13:47:59 (24.12.169.184)
You got 6CA7s that are too hot (hot = higher current under a given set of operating conditions). Your amp does not have sufficient bias adjustment range to bring the current down to spec. There is not .......
342: Tubes Asylum, RE: Tubes tested & burned in (0.00)
Posted by Jim McShane on 2017-02-16, 11:59:28 (24.12.169.184)
If eliminating some infant mortality isn't an improvement in the tube reliability then what is it? .......
343: Tubes Asylum, RE: Tubes tested & burned in (0.00)
Posted by Jim McShane on 2017-02-14, 08:04:10 (24.12.169.184)
I don't totally agree. It will definitely catch some cases of "infant mortality" that otherwise would occur after the tube was sent to the customer. That is a positive step in improved reliability (an .......
344: Vintage Asylum, RE: Cap Values (0.00)
Posted by Jim McShane on 2017-01-30, 16:04:10 (24.12.169.184)
I forgot about that designation since I rarely use ceramics. But if you are looking for them they are C0G (C-zero-G) not C-letter O-G. It may help if you are doing a search. Also, if you want to know .......
345: Vintage Asylum, RE: Cap Values (0.00)
Posted by Jim McShane on 2017-01-30, 14:10:07 (24.12.169.184)
I know you got answers on the questions you had - but I wanted to point out that the 39 pf ceramic cap is an "NPO" capacitor. This is a very high grade cap with tight tolerances and much better specs .......
346: Tube DIY Asylum, RE: 1/3rd and 1/5th watt resistors (0.00)
Posted by Jim McShane on 2017-01-22, 17:36:00 (24.12.169.184)
They aren't that uncommon. IIRC, Fisher and/or Scott used them as did others. .......
347: Vintage Asylum, RE: Is it live, or is it hi fi? (0.00)
Posted by Jim McShane on 2017-01-16, 14:29:10 (24.12.169.184)
Everybody should watch the ALL excerpts that AES has of Edgar Villchur. They are full of remarkable information! Edgar was brilliant! The live vs recorded clip is a favorite of mine as is "Loudspeaker .......
348: Vintage Asylum, RE: Pilot SA260 amp Power Transformer toast? (0.00)
Posted by Jim McShane on 2017-01-15, 13:38:31 (24.12.169.184)
Good news, thanks Mike. .......
349: Vintage Asylum, RE: Pilot SA260 amp Power Transformer toast? (0.00)
Posted by Jim McShane on 2017-01-15, 13:13:36 (24.12.169.184)
Why don't you send it to Gary Brown and have him test and - if required - rewind it for you? Then you know it'll be in good shape and it'll perform properly. And it'll have healthy new lead wires. ::: .......
350: Tubes Asylum, RE: Friend's Jolida 302B blowing fuses....why do they use fast blo fuses in this thing?!? (0.00)
Posted by Jim McShane on 2017-01-13, 09:50:41 (24.12.169.184)
I sent the parts to Paul in January of 2009 - so the now 8 year old caps that were installed then should be fine. But the relocated 220 uf caps are getting a bit long in the tooth so I agree with Tre. .......
351: Tube DIY Asylum, RE: Fixed bias problem, and no, it is not the tubes. (0.00)
Posted by Jim McShane on 2017-01-12, 05:17:23 (24.12.169.184)
So the "leak" path is 50K plus some portion of the pot element resistance. That should be okay but if you can't find anything else causing the problemkeep in mind the total grid circuit resistance is .......
352: Tube DIY Asylum, RE: Fixed bias problem, and no, it is not the tubes. (0.00)
Posted by Jim McShane on 2017-01-11, 19:55:11 (24.12.169.184)
What value are the grid resistors? If they are too high that can cause problems. For the KT-120 with fixed bias the max is 51K - so if you have higher than that it could be the problem. .......
353: Vintage Asylum, RE: Do you want to see a brilliant move? (0.00)
Posted by Jim McShane on 2017-01-11, 08:35:53 (24.12.169.184)
That's because the big carriers use "hub & spoke" routing. You might recall in the early days FedEx had ONE hub - Memphis. ANYTHING sent FedEx (it was Federal Express back then) - even say from Chicag .......
354: Amp/Preamp Asylum, RE: Not Happy, 60 wpc Tube Amplifier (0.00)
Posted by Jim McShane on 2017-01-08, 10:32:20 (24.12.169.184)
I have heard of guys running one Cit II per channel on the Maggies and other difficult loads. It works well since if you have a couple of my "McShaned" (as Mikey Samra calls them) amps you get about 1 .......
355: Tubes Asylum, RE: Genalex tubes who to buy from (0.00)
Posted by Jim McShane on 2017-01-08, 10:24:04 (24.12.169.184)
Are you talking about the current production or the original British made tubes? .......
356: Tubes Asylum, RE: Dunno about that (0.00)
Posted by Jim McShane on 2017-01-07, 11:35:44 (24.12.169.184)
The likely cause of your hum (based on your description) is heater to cathode leakage. If you have AC powered heaters the leakage can induce a hum in the tube. Try running the tube for a few hours the .......
357: Tubes Asylum, RE: Think about it (0.00)
Posted by Jim McShane on 2017-01-05, 14:05:05 (24.12.169.184)
There is no guarantee that new tube sockets and such are pristine though! They can have some tarnish on the metal surfaces, there can be deposits from manufacturing on the tube pins, and so on. You ju .......
358: Tubes Asylum, RE: Does anyone know who owns the Bugle Boy tube logo? (nt) (0.00)
Posted by Jim McShane on 2017-01-05, 05:10:54 (24.12.169.184)
I believe its Richardson Electronics from La Fox IL. IIRC they put the Bugle Boy logo on a bunch of Philips JAN tubes and sold them for high prices. In terms of ownership that's the last I heard anyw .......
359: Tubes Asylum, RE: Jim, I would respectfully disagree......... (0.00)
Posted by Jim McShane on 2017-01-03, 08:54:30 (24.12.169.184)
No, I prefer they don't do it simply as a nod to history. I don't like the products like LED bulbs called "Sylvania" or lesser quality small home appliances labeled "Sunbeam" or "Emerson", and so on. .......
360: Tubes Asylum, RE: Deoxit Gold - Cleaning Abilities (0.00)
Posted by Jim McShane on 2017-01-03, 08:33:59 (24.12.169.184)
That post is pretty old but still worthwhile. You might also find my FAQ post worth checking out. .......
361: Tube DIY Asylum, RE: 6V6 Amp Feedback (0.00)
Posted by Jim McShane on 2016-12-31, 14:05:09 (24.12.169.184)
100K is the top limit of the 6L6GC spec, at least according to GE and RCA. That is the max for fixed bias so that wouldn't bother me at all. For cathode bias the limits are typically 500K. There is no .......
362: Tube DIY Asylum, RE: Jim McShane --- use of 450-500VDC rated caps in bias supply (0.00)
Posted by Jim McShane on 2016-12-31, 13:45:28 (24.12.169.184)
I'm with you 100%! That's a must! What if you encounter a high line voltage situation, just for one concern? .......
363: Tube DIY Asylum, RE: Jim McShane --- use of 450-500VDC rated caps in bias supply (0.00)
Posted by Jim McShane on 2016-12-30, 19:01:35 (24.12.169.184)
Steve, I'm a chicken - and a "belt and suspenders" guy. So I take any reasonable precaution I can think of. There is SOME risk that the value of an electrolytic can lose some of its capacitance in a c .......
364: Tubes Asylum, RE: Less a rip off than calling Russian tubes "Mullard", "Tung-Sol" and "Genelex". Nt (0.00)
Posted by Jim McShane on 2016-12-30, 18:00:59 (24.12.169.184)
Except the Russian tubes clearly say "Made In Russia" on them, either on the base or the glass. And while I prefer not to see it happen as well, New Sensor purchased the names so it was done perfectly .......
365: Tube DIY Asylum, RE: 6V6 Amp Feedback (0.00)
Posted by Jim McShane on 2016-12-30, 14:34:44 (24.12.169.184)
"Is this a grid emission problem? No, not a problem in the sense that the grid emission is excessive; but a situation that can occur if the tube is used with a grid resistance that exceeds the spec. .......
366: Tube DIY Asylum, RE: Yes, but... (0.00)
Posted by Jim McShane on 2016-12-28, 19:26:08 (24.12.169.184)
Thank you for posttng that! I've never seen it before. I have the 1960 schema (the bias supply part is below) which has the bias supply running off a tap on the B+ winding so it's fine with the 600PIV .......
367: Vintage Asylum, RE: No, not a death cap... (0.00)
Posted by Jim McShane on 2016-12-28, 06:06:29 (24.12.169.184)
I'm with Steve - I use 1600 volt caps in that position BTW. The stock voltage is usually 600 volts on vintage gear which I consider too low.I also only use good brands like Panasonic, CDE, etc. ::: TO .......
368: Tube DIY Asylum, RE: Mac Mc30s and Mc60s becareful with the bias supply because you can't use fast switching diodes there, (0.00)
Posted by Jim McShane on 2016-12-28, 06:02:44 (24.12.169.184)
Mike, Just FYI I've been using GI856 diodes in that application (replacing the selenium diode) with ZERO difficulty. Did you have a bad part or ?? I use a 47 uf F&T cap for the bias filter too, rated .......
369: Tube DIY Asylum, RE: G3 (0.00)
Posted by Jim McShane on 2016-12-24, 15:37:34 (24.12.169.184)
So as Chip posted - what do you do when G3 is internally tied to the cathode or the beam formers?? You sure as heck better not tie it to the anode then!! .......
370: Tube DIY Asylum, RE: Pentode or tetrode in triode mode (0.00)
Posted by Jim McShane on 2016-12-24, 09:22:11 (24.12.169.184)
It's hard to be sure what you are asking, but if you are asking what to do when a tube is strapped for triode use... Tie G3 to the tube's cathode. Connect the screen to the plate with a small value re .......
371: Vintage Asylum, RE: Cat Scan completed. (0.00)
Posted by Jim McShane on 2016-12-23, 16:52:45 (24.12.169.184)
Jeff, My best wishes to you and your wife for a pain free future - and a Merry Christmas! Thank you for sharing your experiences. .......
372: Vintage Asylum, RE: Rest and avoidance are now your friends (0.00)
Posted by Jim McShane on 2016-12-22, 15:51:40 (24.12.169.184)
I can't PM you as your account is set up for no email. But feel free to drop me a note if you like - I won't be mad or offended! Thanks for thinking of me! .......
373: Tubes Asylum, RE: Fed up with old stock 12AX7 RCAs dying or becoming microphonic! (0.00)
Posted by Jim McShane on 2016-12-22, 12:14:28 (24.12.169.184)
You would definitely prefer a tube with more top end energy than the Genalex, no doubt! Depending on the circuit you may find it works well in conjunction with other "brighter" toned tubes. I'm 65 yea .......
374: Vintage Asylum, RE: Cat Scan completed. (0.00)
Posted by Jim McShane on 2016-12-22, 10:03:52 (24.12.169.184)
Mike, I know people who have had the same break you have - it does heal but it takes time. And they all tell me it has a useful purpose - after the break heals they say they can tell when a change in .......
375: Tubes Asylum, RE: Fed up with old stock 12AX7 RCAs dying or becoming microphonic! (0.00)
Posted by Jim McShane on 2016-12-22, 09:57:37 (24.12.169.184)
The B759 is quieter with its spiral wound heater; and it has better tone all the way up and down the spectrum. The latest production B759s also have lower microphonics and noise than the earlier produ .......
376: Tubes Asylum, RE: Fed up with old stock 12AX7 RCAs dying or becoming microphonic! (0.00)
Posted by Jim McShane on 2016-12-22, 09:53:16 (24.12.169.184)
I would be willing to bet the Genalex' softer top end is what you heard. It is quite often described in different terms, but "clarity" is usually a product of top end extension/energy. That's why I l .......
377: Tubes Asylum, RE: Fed up with old stock 12AX7 RCAs dying or becoming microphonic! (0.00)
Posted by Jim McShane on 2016-12-21, 16:57:54 (24.12.169.184)
The Tung-Sols have a bit of the same "chime" the RCAs do/did; and the B759 Genalex has a tone quite similar to an old stock Mullard or Amperex. They get along quite well. The reissue Mullard long plat .......
378: Tube DIY Asylum, RE: Resistors, PIV, Current (0.00)
Posted by Jim McShane on 2016-12-21, 12:49:22 (24.12.169.184)
Just FYI, in an addendum/update to the Cit II assembly manual H-K (Stu Hegeman) specified 2.2 meg resistors for diode bypass. Note as well the instruction NOT to cut off excess wire. The wire dissipat .......
379: Tubes Asylum, RE: Fed up with old stock 12AX7 RCAs dying or becoming microphonic! (0.00)
Posted by Jim McShane on 2016-12-21, 12:40:15 (24.12.169.184)
FYI, I find the current production equivalent of the RCA/Mullard mix is the Tung-Sol ECC803S or 12AX7/Genalex B759/ECC83/12AX7 combo. It is a VERY good set of tubes!! .......
380: Tube DIY Asylum, RE: schottkey Diode NOISE (0.00)
Posted by Jim McShane on 2016-12-19, 11:09:54 (24.12.169.184)
Eli was correct. There are rules that apply to some Schottky diodes that do not apply to PN diodes - and not connecting them in series is one of them. That's right from the maker's data for the parts .......
381: Tube DIY Asylum, RE: Thup-thup-thup and static maybe an oscillation (0.00)
Posted by Jim McShane on 2016-12-13, 08:49:02 (24.12.169.184)
I don't mean to be a pest or be insulting about this - but how did you check the sockets? And even if you did check them clean 'em well anyway!! You might be amazed at the dirt in there. It wouldn't h .......
382: Tube DIY Asylum, RE: Thup-thup-thup and static coming from my power amp (0.00)
Posted by Jim McShane on 2016-12-12, 15:46:21 (24.12.169.184)
R54 is a cathode resistor and can be damaged if it gets overheated - one way this can happen is if the tube loses bias and passes excessive current. Is the noise in both channels or just one? That wil .......
383: Vintage Asylum, RE: biaing my Scott 340 receiver questions... (0.00)
Posted by Jim McShane on 2016-12-12, 10:27:55 (24.12.169.184)
Thanks Dave! I agree with you regarding the need to change sockets when they are simply worn out. But I want people to be a bit proactive - clean the sockets whenever you change tubes or maybe once pe .......
384: Vintage Asylum, RE: biaing my Scott 340 receiver questions... (0.00)
Posted by Jim McShane on 2016-12-11, 17:59:00 (24.12.169.184)
You must have a 340A model since the 340B had bias adjustment pots - one for each channel's output tubes - along with the DC balance adjustment. You need a matched quad for you amp. The pair in the fi .......
385: Vintage Asylum, RE: low 12AX7 filament voltage in my Fisher X-100-A amp (0.00)
Posted by Jim McShane on 2016-12-03, 12:27:50 (24.12.169.184)
This is typical of the "cheap Charlie" circuit used by Fisher and others to provide DC power to the heaters of specific tubes. It's quite common to see only 9 or 10 volts across them. You could change .......
386: Tubes Asylum, RE: Thanks it was a nice read but what is the b model (0.00)
Posted by Jim McShane on 2016-11-21, 14:00:27 (24.12.169.184)
That's interesting Tre, thanks for posting it But notice the faceplate doesn't have the "B" letter on it like the Audio Classics amp. I suspect the copy writer and editor on that ad you posted got the .......
387: Tubes Asylum, RE: Thanks it was a nice read but what is the b model (0.00)
Posted by Jim McShane on 2016-11-21, 08:54:01 (24.12.169.184)
There is no IIb - that amp is a Citation II, period. Apparently a previous owner just made up the "b" business and then added a letter (in the wrong font and size) on the front/bottom plate. And the s .......
388: Tubes Asylum, RE: What is the difference between the Citation models (0.00)
Posted by Jim McShane on 2016-11-20, 17:51:40 (24.12.169.184)
The Citation I, II, III, III-X, IV, and V were all tube units. The higher model number units were solid state. I have a complete 1960 product brochure for the tube Citations on my site, check it out. .......
389: Tubes Asylum, RE: Not so Sure About the Tung Sol KT150. (0.00)
Posted by Jim McShane on 2016-11-11, 13:45:28 (24.12.169.184)
Pardon my rant here... but hasn't everybody figured out yet that the tube is only PART of the amp? And that different tubes perform differently in different circuits? The Icon Audio unit the original .......
390: Tubes Asylum, RE: St. Petersburg Winged C 6550 vs. New Sensor Gold Lion KT-88 in Cary SLI-80 Signature (0.00)
Posted by Jim McShane on 2016-11-07, 17:07:12 (24.12.169.184)
The Genalex would be my choice for sure - and a side benefit is the cost may be less than the now scarce 6550Cs. And they can be had properly matched which can be a problem with scarce power tubes lik .......
391: Tubes Asylum, RE: Here is Kevin Hayes' take (of VAC) (0.00)
Posted by Jim McShane on 2016-11-07, 14:24:37 (24.12.169.184)
But a number of well thought of makers use and/or recommend it - ARC for one, and IIRC conrad-johnson for another. It is NOT always a drop-in sub for a KT-88 although in many cases it can sub for it. .......
392: Tubes Asylum, RE: Liability issue versus real problem due to extra current needs (0.00)
Posted by Jim McShane on 2016-11-07, 14:03:41 (24.12.169.184)
The 6201 is not a standard 12AU7 type. It is the "industrial" version of the 12AT7. .......
393: Tubes Asylum, RE: Sylvania Gold Pin 12au7WA = 5814? (0.00)
Posted by Jim McShane on 2016-11-07, 14:02:03 (24.12.169.184)
The 5814 draws a bit more heater current than a 12AU7 - 25 ma. more with 12.6 volts and 50 ma. more at 6.3 volts on the heater. I guess that COULD be why but that would be strange unless there's a bun .......
394: Tubes Asylum, RE: Tube matching w/ amps (0.00)
Posted by Jim McShane on 2016-10-29, 15:07:54 (24.12.169.184)
The Genalex KT77 is a plug and play sub for the EL34. You do need to be sure they'll bias properly in your amp but that's just something you need to tell the tube seller. And if your amp has adjustab .......
395: Tubes Asylum, RE: Tube matching w/ amps (0.00)
Posted by Jim McShane on 2016-10-27, 15:27:58 (24.12.169.184)
I recommend the KT77 Genalex reissue. IMHO they are the best EL34 family type out there, including much of the old stock. If the budget allows grab some, you will be quite pleased I suspect. ::: TOPIC .......
396: Tubes Asylum, RE: Ei KT90 Question (0.00)
Posted by Jim McShane on 2016-10-22, 15:17:07 (24.12.169.184)
Wow, sorry to hear Doug. You've had those for a LONG time - I went through my records to see when you got them and I can't find it. When did you get them, do you recall? .......
397: Tubes Asylum, RE: Ei KT90 Question (0.00)
Posted by Jim McShane on 2016-10-22, 12:25:23 (24.12.169.184)
Those are type III - and as I've posted for over 10 years - you can't tell if the tube is going to red plate or not just by looking at it. It has to be tested. .......
398: Tubes Asylum, RE: Ei KT90 Question (0.00)
Posted by Jim McShane on 2016-10-22, 12:09:58 (24.12.169.184)
Nobody said they didn't sound good. The issue was red plating due to misaligned screens. .......
399: Tubes Asylum, RE: Ei KT90 Question (0.00)
Posted by Jim McShane on 2016-10-21, 17:30:39 (24.12.169.184)
A lot of people had a lot of problems with them - you were lucky to get good ones!! .......
400: Tubes Asylum, RE: Ei KT90 Question (0.00)
Posted by Jim McShane on 2016-10-21, 11:35:21 (24.12.169.184)
It's not 100% sure if he can. The tube needs to be pushed to 40+ watts of dissipation to be sure it is okay. I suspect he can do it but I can't say for sure. .......
401: Tubes Asylum, RE: Ei KT90 Question (0.00)
Posted by Jim McShane on 2016-10-21, 10:58:05 (24.12.169.184)
Despite what has been said there is NO WAY to tell if the tube suffers from the screen misalignment/red plating issues except to run the tube and see. I was able to do that on my test gear, but it's a .......
402: Tubes Asylum, RE: Ei KT90 Question (0.00)
Posted by Jim McShane on 2016-10-21, 09:37:19 (24.12.169.184)
As Mendel said the "wings" on the plates indicate type III. But type IIIs weren't made in the 1980s AFAIK. And honestly I've had very little luck with Ei coding. I'd bet this tube is from later produc .......
403: Tube DIY Asylum, RE: Russian K40 Prices (0.00)
Posted by Jim McShane on 2016-10-20, 16:19:09 (24.12.169.184)
As Mike said the price difference is based on supply and demand, with the 630 volt caps being in a significantly tighter supply situation. Also, FWIW I can't hear any difference at all between the dif .......
404: Tubes Asylum, RE: RCA 5963 are these any good for audio (0.00)
Posted by Jim McShane on 2016-10-12, 09:22:50 (24.12.169.184)
He's referring to the 5963, NOT the 5693. The 5963 is similar to and often used as a sub for a 12AU7. .......
405: Tube DIY Asylum, RE: Yes, I have read that. (0.00)
Posted by Jim McShane on 2016-10-02, 10:57:55 (24.12.169.184)
The most current new production GZ34s (Genalex, Tung-Sol, and Mullard) are FAR better than the older Sovtek/Shuguang/and cetainly JJ!) stuff. I can't understand why people chase the old stock anymore .......
406: Tube DIY Asylum, RE: These caps are new. (0.00)
Posted by Jim McShane on 2016-10-01, 18:20:41 (24.12.169.184)
You had a JJ? That explains a lot. JJ octal tubes are - let's just say "suspect" regarding quality. .......
407: Tube DIY Asylum, RE: Today my GZ34 rectifier flashed.... (0.00)
Posted by Jim McShane on 2016-10-01, 11:37:45 (24.12.169.184)
But how old are the caps in the supply? Leaky caps KILL rectifier tubes! .......
408: Vintage Asylum, RE: LOOK at this. Going 14.5 years with Jim McShane! (0.00)
Posted by Jim McShane on 2016-09-28, 10:59:13 (24.12.169.184)
Thank you all for your kind words. I didn't realize it had been that long, wow! Hopefully there'll be another 14.5 fun years ahead!! .......
409: Tube DIY Asylum, RE: Triode Kingdom reminded me of a very good point the other day. (0.00)
Posted by Jim McShane on 2016-09-16, 07:52:41 (24.12.169.184)
One thing you need to be aware of - I find Hammond chokes spec for DC resistance and what they actually measure to be quite different. I used to use a Hammond that was supposed to be about 260 Ohms - .......
410: Tubes Asylum, RE: Here is a gentleman that did an EL34 shootout and I agree with most of it. (0.00)
Posted by Jim McShane on 2016-09-13, 07:22:28 (50.151.166.185)
Hi Danny, The RFTs (not RTF) are quite durable, they were made in E. Germany by one of the lesser known but (IMHO) highest quality tube makers. So it is very durable, yes, even more than many other ol .......
411: Tubes Asylum, RE: Here is a gentleman that did an EL34 shootout and I agree with most of it. (0.00)
Posted by Jim McShane on 2016-09-12, 17:10:13 (50.151.166.185)
Have you heard the KT-77 Genalex? Yes, the RFTs are nice too, no doubt. But I'm with Mikey - the Genalex reissues are the best, at least IMHO. .......
412: Tubes Asylum, RE: Safe Triode Balance? (0.00)
Posted by Jim McShane on 2016-09-10, 12:34:14 (50.151.166.185)
Those are apparently some sort of tester readings of transconductance. Those readings are quite close to each other and are just fine. FYI, there would be no risk to the amp even if the difference was .......
413: Tubes Asylum, RE: Should I replace a tube socket in a Sherwood S-5000 (0.00)
Posted by Jim McShane on 2016-09-08, 11:01:56 (50.151.166.185)
You can do just one if that is the only one that's acting up! .......
414: Tubes Asylum, RE: Should I replace a tube socket in a Sherwood S-5000 (0.00)
Posted by Jim McShane on 2016-09-08, 10:31:10 (50.151.166.185)
Charles, Be VERY careful using that stuff. It ends up everywhere and since it is conductive it can cause a lot of trouble. Geezerrocket's advice about "less is more" is spot on. In fact I don't recomm .......
415: Tubes Asylum, RE: reading lots/manufacture dates on EH tubes (0.00)
Posted by Jim McShane on 2016-09-06, 14:19:38 (50.151.166.185)
That's July of 2002. But don't put a lot of faith in the "matching" numbers. The "factory" or "distributor" match is not so hot. Also realize Ip stands for plate current - yet when adjusting the bias .......
416: Tubes Asylum, RE: reading lots/manufacture dates on EH tubes (0.00)
Posted by Jim McShane on 2016-09-06, 10:13:36 (50.151.166.185)
Yes, there is a four digit date code. The first two numbers are the year, the last two are the month. .......
417: Tube DIY Asylum, RE: "make tonal changes to the amp" (0.00)
Posted by Jim McShane on 2016-09-05, 20:01:41 (50.151.166.185)
My reference to tonal changes wasn't limited to the regulator idea Chip. I meant in general - different tubes, etc., as well. Sorry I wasn't more clear. .......
418: Tube DIY Asylum, RE: Thanks, for explanation (0.00)
Posted by Jim McShane on 2016-09-05, 16:21:37 (50.151.166.185)
There is no matching needed in the Cit II input tubes beyond them being reasonably close (as opposed to one strong and one weak tube). What we found some years back with some input from Norm Thagard ( .......
419: Tubes Asylum, RE: This is precisely why I bought 250 cinch NOS sockets to fit (0.00)
Posted by Jim McShane on 2016-09-05, 15:57:37 (50.151.166.185)
Yes - cleaning and maintenance! .......
420: Tube DIY Asylum, RE: Way more complexity and a potentially butchered amp? (0.00)
Posted by Jim McShane on 2016-09-04, 15:48:17 (50.151.166.185)
Chip, Just FYI - the input tubes on the Citation II run at about 20 ma. cathode current. The screens are well decoupled in the stock amp using R-C filters with 50uf caps in each channel - and we recom .......
421: Tubes Asylum, RE: Belton sockets Jim? (0.00)
Posted by Jim McShane on 2016-09-04, 15:11:51 (50.151.166.185)
Hi Tim, They are made in South Korea, and they actually ARE very modestly priced. What I meant was that NOS stuff is now getting pricey; sorry if I wasn't too clear. Most tube vendors (including me - .......
422: Tubes Asylum, RE: This is precisely why I bought 250 cinch NOS sockets to fit (0.00)
Posted by Jim McShane on 2016-09-04, 13:32:43 (50.151.166.185)
Mikey, After reading your post I wanted to pass along my opinion on NOS vs Belton sockets. IMHO the 9 pin chassis mount Beltons are superior in every way to the NOS. When I had NOS Cinch 9 pins to put .......
423: Tubes Asylum, RE: Replace them with NOS US made sockets (0.00)
Posted by Jim McShane on 2016-09-03, 10:15:34 (50.151.166.185)
I have to take issue with your advice Chip. And I do so simply because retensioning of tube sockets (IMHO) is "normal maintenance" for tube gear. As I've posted in my FAQ entry, poor pin to socket con .......
424: Tubes Asylum, RE: Pentode/Triode Operating Points (6BL8,6U8,6GH8,7199 etc) (0.00)
Posted by Jim McShane on 2016-08-30, 13:13:13 (50.151.166.185)
That's not uncommon. The Cit II uses a higher screen supply on the 12BY7A pentodes as well. .......
425: Tubes Asylum, Understood! (0.00)
Posted by Jim McShane on 2016-08-24, 17:05:24 (50.151.166.185)
There are a lot of people who don't realize how good the 3 rectifiers I mentioned are, so I thought I'd ask if you knew of them. .......
426: Tubes Asylum, RE: Mike, I wouldn't use a VR in any tube amp I'll own. (0.00)
Posted by Jim McShane on 2016-08-24, 13:13:40 (50.151.166.185)
"Good real NoS GZ34s which are the ONLY good GZ34s around now," Did you try the recent releases - the Genalex U77, or the Tung-Sol or Mullard branded 5AR4/GZ34s? .......
427: Tubes Asylum, RE: Current KT88 with least bass bloat (0.00)
Posted by Jim McShane on 2016-08-21, 12:00:40 (50.151.166.185)
We use the Genalex KT-88s in our Citation II amp rebuilds - they are absolutely great. No bass bloat at all. Superb tube! .......
428: Tube DIY Asylum, RE: Standby switch...pros and cons? (0.00)
Posted by Jim McShane on 2016-08-20, 09:34:37 (50.151.166.185)
I would have chosen a device with a higher cold resistance and a longer time constant. A CL-140 (50 Ohms cold vs. 10 Ohms for a CL-120) would have been my choice. Also, I've never had any luck using t .......
429: Tubes Asylum, RE: How about trying 12BH7 in the driver tube position (0.00)
Posted by Jim McShane on 2016-08-20, 09:28:09 (50.151.166.185)
Yes. I recommend the 12BH7 for the "center" position and then use 12AU7s for the other sockets. It works VERY well! .......
430: Tube DIY Asylum, RE: Totally agree ... (0.00)
Posted by Jim McShane on 2016-08-17, 17:15:17 (50.151.166.185)
"Hopefully it was conduction *at rated/maximum power*...:)" I know what you are saying Doug, and for purposes of accurately describing an amplifier's design I agree 100%. But from a purely engineeri .......
431: Tubes Asylum, RE: Warmer sounding output tubes in VTA 70 (0.00)
Posted by Jim McShane on 2016-08-17, 09:18:22 (50.151.166.185)
Charles, You might like the 6CA7 EH output tubes. Have you tried them? .......
432: Tubes Asylum, RE: Look what I founded in your attic Mommy. (0.00)
Posted by Jim McShane on 2016-08-16, 08:50:50 (50.151.166.185)
Wow, that's surprising that they didn't come down. Thanks much for the clarification. Just FYI I ran mine at 465 volts on the plate and screen and -50 on the grid which usually resulted in cathode cur .......
433: Tubes Asylum, RE: Look what I founded in your attic Mommy. (0.00)
Posted by Jim McShane on 2016-08-15, 10:00:02 (50.151.166.185)
If you have a way to run them the gassy tubes will be fine after a good run in. But don't use ANY of the 6P3S-Es unless you test them thoroughly, especially for grid current/gas. .......
434: Tubes Asylum, RE: 8417 tubes and their history. (0.00)
Posted by Jim McShane on 2016-08-10, 07:40:14 (50.151.166.185)
Apparently 8417 tubes were quite difficult to make as well. In fact some say the only good 8417 is a Sylvania, the GEs had some grid issues IIRC. The very high Gm of the 8417 (about 50% higher than a .......
435: Tubes Asylum, RE: 7189 and 6BQ5 - Plate Voltage and Dissipation (0.00)
Posted by Jim McShane on 2016-08-03, 14:22:32 (50.151.166.185)
Exactly! You cannot compare tube specs unless you know what rating system was used: 1. Design-center - the most conservative and most commonly used; the most tube-friendly of the three systems 2. Desi .......
436: Tubes Asylum, RE: The 6P14EV and EL84M are the same tube AFAIK (0.00)
Posted by Jim McShane on 2016-07-21, 11:57:20 (50.151.166.185)
Tim is correct. The EL84M designation is just the Sovtek numbering for the 6P14P-EV (or EB) tube. .......
437: Tubes Asylum, RE: EL84 Russian Military 6P14P-EV- (0.00)
Posted by Jim McShane on 2016-07-21, 09:03:10 (50.151.166.185)
I can tell you from experience that the match on those "quads" is suspect. Properly matched quads are hard to find, so what I take as your inference that I am misrepresenting the availability is not a .......
438: Tube DIY Asylum, RE: "few hundreds of mA, max." (0.00)
Posted by Jim McShane on 2016-07-19, 08:02:59 (50.151.166.185)
That's likely still more than needed. The amount of current through the tube grid is measured in microamps - with the exception of tubes/gear designed to push the tube grids into positive voltages! Th .......
439: Tubes Asylum, RE: You aren't raining on our parade and I'm glad you chimed in. (0.00)
Posted by Jim McShane on 2016-07-17, 19:48:01 (50.151.166.185)
I've found they do a fairly decent job on many (not all, but most) power tube Gm readings - but as you say - what test conditions were the tubes subjected to? Hey, Gm readings on a given tube vary fro .......
440: Vintage Asylum, RE: Magnavox 9303 amp question... (0.00)
Posted by Jim McShane on 2016-07-17, 19:15:47 (50.151.166.185)
Wait just a minute! The new Tung-Sol 6EU7s are very good. There is no shortage of good 6EU7s anymore as a result. Its a lot of work to rewire those sockets, I'd recommend keeping the 6EU7s. ::: TOPIC: .......
441: Tubes Asylum, RE: Michael, a broader question (0.00)
Posted by Jim McShane on 2016-07-17, 19:00:46 (50.151.166.185)
I hate to rain on everyone's parade - but the Gm of a tube varies with the operating conditions under which the tube is being run. So unless you can test using the exact conditions (or quite close to .......
442: Tubes Asylum, RE: Server Not Found (0.00)
Posted by Jim McShane on 2016-07-14, 17:57:13 (50.151.166.185)
It's fixed - it's the Tube Asylum FAQ. .......
443: Tubes Asylum, RE: Have you tried a know, good set of EL84? (0.00)
Posted by Jim McShane on 2016-07-14, 11:19:22 (50.151.166.185)
Or you can simply install a new production Tung-Sol or Genalex - problem solved! BTW, if it was my amp I'd remove the 18 Ohm resistor and install a 10 Ohm 1 watt resistor at EACH EL84 tube cathode so .......
444: Vintage Asylum, RE: I got some measurements so far (0.00)
Posted by Jim McShane on 2016-07-12, 08:34:14 (50.151.166.185)
Make sure the bracket is thick enough, and also make sure you look carefully at the picture I posted for where the clamps mounting holes go along with the other holes in the bracket. The same goes for .......
445: Vintage Asylum, RE: I got some measurements so far (0.00)
Posted by Jim McShane on 2016-07-11, 09:49:45 (50.151.166.185)
Also the holes for mounting the caps are 1.375" diameter except the one for the old bias cap which is at the opposite end of the bracket from Mike's picture. But I'd make it the same size as the other .......
446: Vintage Asylum, RE: HK Citation II PS bracket (0.00)
Posted by Jim McShane on 2016-07-08, 10:14:19 (50.151.166.185)
FYI - that is one of my early PS kits installed on the bracket. So if you think my kits are okay it might be a better deal. The inrusk limiter strip and the large Panasonic film caps are installed .......
447: Vintage Asylum, RE: HK Citation II PS bracket (0.00)
Posted by Jim McShane on 2016-07-07, 19:38:21 (50.151.166.185)
You need a PS bracket and the terminal boards to put the amp back together. I don't have a bracket nor do I know of anyone who can supply a dimensional drawing to have one made. The bracket also serve .......
448: Tubes Asylum, RE: "Matched" power tubes, what am i missing? (0.00)
Posted by Jim McShane on 2016-07-05, 08:48:37 (50.151.166.185)
You might find my post regarding "tube problems" in the FAQ to be useful, check it out at the link below. Item #6 in my post details why a responsible dealer will try to verify what is occurring befor .......
449: Tube DIY Asylum, RE: Wooo-Hooo...finally scored a Cit.II OPT (0.00)
Posted by Jim McShane on 2016-06-29, 16:07:42 (50.151.166.185)
FYI - the earlier units were around 270 KHz - and the later ones were about 450 KHz. This is according to H-Ks own publications. I've never measured them personally. .......
450: Tubes Asylum, RE: Misrepresentation In eBay Auction (0.00)
Posted by Jim McShane on 2016-06-22, 12:04:37 (50.151.166.185)
I didn't complain on this case because the auction closed before I could. But I definitely will in the future. .......
451: Tubes Asylum, Misrepresentation In eBay Auction (0.00)
Posted by Jim McShane on 2016-06-21, 09:39:10 (50.151.166.185)
There was a sale yesterday of a Citation II amp on eBay: HARMAN KARDON Citation II Stereo Tube Power Amplifier 6550 KT88 KT120 #131844552498 In the description my name was mentioned in this context: .......
452: Tubes Asylum, RE: Reissue GL or Psvane KT88 II (0.00)
Posted by Jim McShane on 2016-06-15, 07:49:49 (50.151.166.185)
Let me also point out that in a high bias current amp like a Citation II the KT-88s break in much quicker. Whether your ears "break-in" quicker I can't say, but I agree with Mikey. I had original Gena .......
453: Amp/Preamp Asylum, RE: Fair enough (0.00)
Posted by Jim McShane on 2016-06-02, 18:58:44 (50.151.166.185)
The schematic is on the ARCDB site (link below). Scroll down that page and the Mk II schema is there. .......
454: Amp/Preamp Asylum, RE: Here's the distinction (0.00)
Posted by Jim McShane on 2016-06-02, 15:46:23 (50.151.166.185)
Abe is correct. I looked at the schematic, and as you would expect the output stage is a cathode follower. Cathode followers (a.k.a. "buffers") have a voltage gain of less than 1. In other words - no .......
455: Vintage Asylum, RE: I would love a 32v3 (0.00)
Posted by Jim McShane on 2016-05-27, 12:17:15 (50.151.166.185)
"I should send McShane over there." On no you don't!! I'm already in enough trouble here... .......
456: Tubes Asylum, RE: replacement for 7868 tubes (0.00)
Posted by Jim McShane on 2016-05-24, 17:08:14 (50.151.166.185)
What do you mean? They are in production now, many of the AA sponsors (and others) carry them. They are easy to get (even matched sets) and plentiful. As well, they are FAR less costly than the little .......
457: Tubes Asylum, RE: replacement for 7868 tubes (0.00)
Posted by Jim McShane on 2016-05-24, 15:30:16 (50.151.166.185)
Yes, that's my feelings exactly. And keep in mind for many vintage amps you need matched quads of 7868s - where are you going to get those? Just go with the excellent sounding EH and you'll be set. :: .......
458: Tubes Asylum, RE: HK Citation One heater lines (0.00)
Posted by Jim McShane on 2016-05-17, 10:15:11 (50.151.166.185)
No. Only the phono stage tubes are grounded, just as it's shown in the schematic. BTW the voltages on the rails are about + and -11.5 volts. The 12AT7 and 12AX7 require about 12 volts when using pins .......
459: Tube DIY Asylum, RE: any one here using kiwame resistors on grids stopper ? (0.00)
Posted by Jim McShane on 2016-05-11, 18:10:02 (50.151.166.185)
Since the current through the grid stopper is miniscule the "microarcing" noise from a carbon comp resistor is not an issue. I try to use them whenever possible. The near total lack of inductance make .......
460: Vintage Asylum, RE: Eli, you happen (0.00)
Posted by Jim McShane on 2016-05-09, 15:29:28 (50.151.166.185)
I'm not Eli, but the current production version of the 6P14P-EV is the Sovtek EL84M. Nice sounding, TOUGH tube! .......
461: Tube DIY Asylum, RE: PIO coupling caps and leakage? (0.00)
Posted by Jim McShane on 2016-04-26, 07:55:19 (50.151.166.185)
I'm 100% with Mikey on this. I have had ONE K40 with an issue out of all the ones I've handled. And while I haven't had the amount of exposure to the other NOS oilers he mentioned I have no reason to .......
462: Tube DIY Asylum, RE: On Capacitors.. (0.00)
Posted by Jim McShane on 2016-04-25, 08:21:36 (50.151.166.185)
Lee, my apologies - I interpreted your post to mean you were disappointed! Thanks for setting me straight. .......
463: Tube DIY Asylum, RE: Need help from Jim McShane (0.00)
Posted by Jim McShane on 2016-04-25, 08:20:35 (50.151.166.185)
You're very close - connect the turntable to Phono 1 on the Cit I - that's the input for a modern phono cartridge. Otherwise you have it nailed. The lowest capacitance high quality cable I know of is .......
464: Tube DIY Asylum, RE: On Capacitors.. (0.00)
Posted by Jim McShane on 2016-04-24, 18:06:23 (50.151.166.185)
Lee, your experience runs counter to (I'd say) 95% plus of the experiences I've had personally or have knowledge of. I can tell you that often the older caps (especially older Mylar/polyester caps) ha .......
465: Tube DIY Asylum, RE: Need help from Jim McShane (0.00)
Posted by Jim McShane on 2016-04-22, 13:30:46 (50.151.166.185)
You can pick up the signals from the phono stage at the Tape Out jacks. When you do that all the controls (volume, balance, tone controls, etc.) are inoperative except the Turnover and Rolloff control .......
466: Tube DIY Asylum, RE: I love our Constitution, our government is fleecing us blind with corporate welfare PCBs are overblown hazard (0.00)
Posted by Jim McShane on 2016-04-15, 15:06:25 (50.151.166.185)
Come on Mike - you MUST know that the move to severely restrict use and sale of R-12 was put into place by an INTERNATIONAL agreement, the Montreal Protocol. That agreement was ratified during the RON .......
467: Tubes Asylum, RE: Extinct?? (0.00)
Posted by Jim McShane on 2016-04-07, 13:19:17 (50.151.166.185)
I ran out and couldn't get more other than onesy-twosies! .......
468: Tubes Asylum, RE: Jim, just to be clear... (0.00)
Posted by Jim McShane on 2016-04-07, 08:15:49 (50.151.166.185)
I'd be willing to place a bet that says most of that gear never gets used. I have the same thing occur here. I don't have as much test gear as shown in that picture he posted, but even with less gear .......
469: Tube DIY Asylum, RE: Here this is a catalog I found on Russian capacitors (0.00)
Posted by Jim McShane on 2016-04-06, 07:26:44 (50.151.166.185)
Thanks for sharing it Mike, it'll be very helpful! .......
470: Tubes Asylum, RE: Jim, just to be clear... (0.00)
Posted by Jim McShane on 2016-04-05, 09:15:44 (50.151.166.185)
The Philips family tubes (and companies that used Philips machinery/parts later such as Ei) are the ones that use the high inrush current heaters. There are others like (IIRC) the 2E26 that flash at s .......
471: Tubes Asylum, RE: Tech's view on European tubes heater flash (0.00)
Posted by Jim McShane on 2016-04-04, 20:06:10 (50.151.166.185)
I'm sorry, but... If this is true how come we don't have piles of dead ECC series Bugle Boys lying around our benches? I have NEVER had a "flasher" fail due to an open heater. NEVER. And a lot of them .......
472: Tube DIY Asylum, RE: Sprague Vitamin Q (again) (0.00)
Posted by Jim McShane on 2016-03-30, 18:09:48 (50.151.166.185)
ALL K40Y caps are PIO. Whether there is oil free to run out of the cap isn't indicative of their construction. Paper saturated in oil is the dielectric. .......
473: Tube DIY Asylum, RE: Jim, good to see you are ok. (0.00)
Posted by Jim McShane on 2016-03-30, 18:05:43 (50.151.166.185)
Thanks for the kind words Steve (and everyone!). I still have some issues but I'm WAY better than even a week ago. I'm headed back to the doctor tomorrow to see if I need any more help. Those Cornings .......
474: Tube DIY Asylum, RE: Help needed identifying resistor manufacturer (pic) (0.00)
Posted by Jim McShane on 2016-03-30, 15:24:13 (50.151.166.185)
They were made by Corning Glass Works, thus the CGW marking. They are really good resistors, but they are so old now that they are crumbling in some cases. They are not made anymore, but I may be able .......
475: Tubes Asylum, RE: Reputable online vacuum tube stores (0.00)
Posted by Jim McShane on 2016-03-21, 15:35:23 (50.151.166.185)
Thank you for the kind words. I did want to mention that I haven't been able to live up to the "fast" part for a bit though. I contracted a severe viral infection right about March 3rd and today (the .......
476: Tubes Asylum, RE: Jim, thanks for that link (0.00)
Posted by Jim McShane on 2016-03-06, 13:13:29 (50.151.166.185)
You're close! What I said was I wasn't a big fan (or a fan at all) of the SLI-80 power supply. There is a lot that can be done to improve it and to make life much easier on the rectifier at the same t .......
477: Tube DIY Asylum, RE: Yes, thanks. On related note, what size coupling caps .... (0.00)
Posted by Jim McShane on 2016-03-05, 11:29:17 (50.151.166.185)
With 330K grid resistors following a .025 uf cap the cutoff point is pretty high - about 19.5 Hz. That means that you'll have some loss of low frequencies to at least 40 Hz. It may be that the bandwid .......
478: Tubes Asylum, RE: why change, he asks... (0.00)
Posted by Jim McShane on 2016-03-05, 11:15:38 (50.151.166.185)
"I suspect those tubes are running hotter than the design calls for" Actually exactly the opposite is true. .......
479: Tubes Asylum, RE: Biasing KT-77s in a Conrad-Johnson MV-60 (0.00)
Posted by Jim McShane on 2016-03-05, 11:14:11 (50.151.166.185)
He can use the KT-77 Genalex just fine, I help c-j owners fit KT-77 Genalex to their amps all the time. And they are FAR from worse, they are amazing tubes!! He just needs to get them from a vendor wh .......
480: Tube DIY Asylum, RE: Just an improvement (0.00)
Posted by Jim McShane on 2016-03-04, 15:33:45 (50.151.166.185)
I think the improved parts and some of the other things you do are GREAT Steve. I suspect that the amps you've done are far better now that you've redone them. But without some help from you or other .......
481: Tube DIY Asylum, RE: The ol' solving problems you don't have psychosis (0.00)
Posted by Jim McShane on 2016-03-04, 08:10:55 (50.151.166.185)
What Chip said! And please excuse the editorial opinion- but in my opinion MOST (not all, most) guitar amps are usually marginal products anyway. I'm not saying they can't create terrific tones, but I .......
482: Tubes Asylum, RE: Cary SLI-80 tube bias (0.00)
Posted by Jim McShane on 2016-03-04, 07:53:42 (50.151.166.185)
That is for more than one tube, yes? "Little details" like that are critical. That's why people need to pay attention to the maker's bias recommendations. That's not to say you can't try different se .......
483: Tube DIY Asylum, RE: ramp down (0.00)
Posted by Jim McShane on 2016-03-03, 19:16:34 (50.151.166.185)
Tubes! It has tubes... The tubes don't stop conducting immediately since the tubes' cathode temperatures stay high enough to conduct for some time after the power is turned off. You must have heard a .......
484: Tubes Asylum, RE: Cary SLI-80 tube bias (0.00)
Posted by Jim McShane on 2016-03-03, 10:53:11 (50.151.166.185)
It is VERY risky to set bias by ear! The bias current setting depends on the amp, not just the tube. For instance, 75 ma bias current and 400 plate volts gives you 30 watts of plate dissipation, that' .......
485: Tubes Asylum, RE: Ping Jim On GL KT-88"s (0.00)
Posted by Jim McShane on 2016-03-03, 10:46:54 (50.151.166.185)
Those numbers in black marker are cathode current, not Gm. They are a very close match already (better than 2%!) so you can pair up any two in a given channel. Believe me, the electronics in the amp a .......
486: Tubes Asylum, RE: Yes, I suggested 48 Watts (0.00)
Posted by Jim McShane on 2016-03-01, 15:10:40 (50.151.166.185)
And I agree with the 48 watt suggestion. I wanted to point out the rating system difference between the KT150 and many other power tubes though. You can't compare one to the other without knowing the .......
487: Tubes Asylum, RE: It is a 70 watt plate dissipation tube. (0.00)
Posted by Jim McShane on 2016-03-01, 07:42:40 (50.151.166.185)
I would caution that the KT150 ratings are listed under the "Design Maximum" rating. This is a less conservative rating scenario than the common "Design Center" values which are used on many tubes. I .......
488: Tubes Asylum, Thank you so much for your very kind words (nt) (0.00)
Posted by Jim McShane on 2016-02-25, 06:38:52 (50.151.166.185)
.......
489: Tubes Asylum, RE: NOS ? (0.00)
Posted by Jim McShane on 2016-02-24, 05:55:54 (50.151.166.185)
Pins are discolored quite often on brand new old stock tubes. That is NOT a reliable way to tell if a tube has been used. That's all I'm going to say. Buy tubes from a reputable source and you have no .......
490: Amp/Preamp Asylum, RE: AES SixPacs - Replacing caps? (0.00)
Posted by Jim McShane on 2016-02-23, 08:43:01 (50.151.166.185)
The K40 Russian caps are VERY reliable and quite nice tonally. Don't be afraid to use them, we do on the Citation amps we overhaul - ZERO failures with 100s of them in service. .......
491: Tubes Asylum, RE: New Power Tubes For Jolida JD-303CRC Amp (0.00)
Posted by Jim McShane on 2016-02-21, 08:22:32 (50.151.166.185)
If you can swing a set of the Genalex KT-77 reissues I think you'll be very pleased. Properly selected KT-77 Genalex will drop right in and bias fine. GREAT tubes! .......
492: Tubes Asylum, RE: EH EL34 - are these fakes (different green color) (0.00)
Posted by Jim McShane on 2016-02-18, 07:17:34 (50.151.166.185)
Come on now... by that definition anyone who made an EL34 other than Philips was a counterfeiter! That strikes me as a bit over the top. The color of the logo on the EH has changed a number of times - .......
493: Tubes Asylum, RE: Looking for something different. KT66 or 77? (0.00)
Posted by Jim McShane on 2016-02-17, 12:38:44 (50.151.166.185)
"The KT77s sounded like a poor cross between an EL34 and a KT88, with a discontinuity between the frequency ranges." Just so everyone knows - this is NOT a widely held view. I'm not saying he's wron .......
494: Vintage Asylum, RE: how about the "Five"? (0.00)
Posted by Jim McShane on 2016-02-17, 05:27:07 (50.151.166.185)
I should point out that there a a number of people that prefer the Cit V to the Cit II. I personally think the V has better imaging which when paired with the outstanding tone makes it a very formidab .......
495: Vintage Asylum, RE: HK Citation II modern equivalent? (0.00)
Posted by Jim McShane on 2016-02-15, 06:55:14 (50.151.166.185)
They are quite different. Not only the transformers, but the new amp uses a 5AR4 instead of the SS rectifier in the original. The new amp is monobloc construction. The new amp has 10 watts less RMS po .......
496: Vintage Asylum, RE: The two best things you can do to most speakers of the era is to change the cap(s) (0.00)
Posted by Jim McShane on 2016-02-12, 12:00:31 (50.151.166.185)
Do keep in mind that changing to a decent film cap from the original electrolytics WILL change the speaker voicing. The much lower ESR of a modern high quality film cap is definitely a reduction from .......
497: Tube DIY Asylum, RE: You don't want the atoms (0.00)
Posted by Jim McShane on 2016-02-11, 06:19:44 (50.151.166.185)
I mostly agree with Russ - but there are some occasions where the Atom is helpful in achieving a certain tone. And they are axial, and there aren't a lot of axial caps around anymore. .......
498: Tubes Asylum, RE: Conduction Angle (0.00)
Posted by Jim McShane on 2016-02-10, 06:10:50 (50.151.166.185)
What Eli said! The small second filter of the choke and cap makes a noticeable improvement. I know Mikey agrees too because we've talked about it on occasion. .......
499: Tubes Asylum, RE: Need help with KT-88 that tests good but plays bad (0.00)
Posted by Jim McShane on 2016-02-08, 06:53:04 (50.151.166.185)
Yes indeed. Or a wire that is broken inside the insulation where it can't be seen! That's why I have all this gray hair... .......
500: Tubes Asylum, RE: Need help with KT-88 that tests good but plays bad (0.00)
Posted by Jim McShane on 2016-02-07, 10:11:57 (50.151.166.185)
YES!! Jonesy nailed it spot-on! If that doesn't fix it THEN you can condemn the tube. .......
Found total of 500 records, Query: , Author: Jim McShane in All Forums, Time: 2 sec.