Tubes

Reading Tube Specs

feeds@yuku.com (jbmojo) — Sat, 07 Nov 2009 21:39:18 GMT

This will sound dumb but how does one read tube specs? I see things like "Ia(o), Ia(b). Is that the current draw at idle and full load? What's a good link for a rosetta stone on tube specs?
Some of the figures I see do this number on me-

KT66 heater current

feeds@yuku.com (StoSoStu) — Fri, 23 Oct 2009 00:33:57 GMT

Is anyone aware of a current manufactured KT66 that only draws 900 mA of heater current, like the original Mullards? I have some QUAD amps in that need new KT66s but all the current manufactured ones I look at draw 1.3 - 1.6 A of heater current and the owner is worried that the extra current draw will burn up his PT. The ones I have looked at are Gold Lion, Shuguang, and Saratov which all draw too much heater current. I couldn't find the heater current data for JJs, and the owner...

This is amazing you guys have to see this!

feeds@yuku.com (spoony) — Tue, 13 Oct 2009 19:09:13 GMT

Maybe this has all ready been posted? When I saw this I felt if any group of guys would appreciate this it would be everyone on this forum.

http://www.youtube.com/watch?v=gl-QMuUQhVM&feature=related

spoony

AVO VCM Mk2 tube tester question

feeds@yuku.com (jambogus) — Sun, 20 Sep 2009 18:39:36 GMT

I don't know when my AVO VCM Mk2 was last calibrated and I suspect it is supplying erroneous results, so I thought I should check it now. I have the manual and it has instructions for calibration, but they are not very precise. As a non-electronic person, I don't want to damage either the tester or myself. If anyone here has experience of calibrating this type of tester, I would be grateful for some assistance.

KT90,99,100 info

feeds@yuku.com (jbmojo) — Wed, 09 Sep 2009 19:08:44 GMT

Lookin' for info/opinions on KT90, KT99, & KT100's along w/ sources to obtain them. Anybody had any experience with these critters?

Shuguang Valves

feeds@yuku.com (StoSoStu) — Tue, 04 Aug 2009 20:10:54 GMT

Anybody used these? Any comments, good bad, indifferent? Specifically their EL34 and 6L6GC, as they have recently become available locally at very good prices.

purchased New Microtech TechTube™ Blackburn Legacy Series E813CC valve

feeds@yuku.com (blee) — Thu, 16 Jul 2009 21:00:30 GMT

I purchased one of the new tubes being made at the old Mullard factory in England the .TechTube™ Blackburn Legacy Series E813CC valve which suppose to be a 12ax7/ecc83 direct replacement. I got the first one & put it in the V1 position of my guitar amp & it sounds amazing so I ordered another one. I got it today & put it in the V2 position & it dropped the gain & volume way down & in the V3-V5 position it does not even work but works in the V1. Any body know why?

Current production 5Y3 tubes. Which one to use??

feeds@yuku.com (Fenderonly) — Wed, 08 Jul 2009 20:13:53 GMT

Seems my choices are Sovtek and Fender. Is the 5Y3 by Fender the same tube or made by someone else? I have also read the Sovtek is more like a 5V4 as far as its internal resistance. Any one know if the voltage drop is true to the norm for a 5Y3 on the Sovtek tube?

I need to get 22 ordered for my 5D6 amps I am building. Any help or advise appreciated.

5751

feeds@yuku.com (jbmojo) — Sat, 02 May 2009 08:46:06 GMT

Where does a 5751 go in the hierarchy of tubes? Same as 12AX7? 12AU7? Or in-between? Just curious since I got some in a bunch of tubes someone gave me. BTW, the're Sovteks.

12DW7 Brown Deluxe

feeds@yuku.com (Jammin John) — Wed, 29 Apr 2009 08:17:51 GMT

I got a humbucker guitar and am looking for some clean headroom in the 'ole Brown Deluxe. I put 12AY7's in v1 & v2 and a 12DW7 in v3. The DW has a gain factor of 100 on one side and 20 on the other. Will this hurt anything ? It sounds good and is a lot cleaner. JJ

CV492 same as 12AX7?

feeds@yuku.com (Idunknow) — Wed, 04 Mar 2009 19:18:31 GMT

CV492 same as a 12AX7?

CBS & Westinghouse tubes?

feeds@yuku.com (Idunknow) — Mon, 02 Mar 2009 21:24:19 GMT

I see some Westinghouse, CBS, & Ratheon tubes here & there for sale but know nothing about them. Never had any to try out. So, I am currious about who exactly made these tubes & what kind of tone they have, say a 12AX7 CBS, Westinghouse, or Ratheon compared to a GE, RCA, Telefunken, Philips, or Mullard which I am familiar with. I Know Westinghouse made thier own tubes but not sure about CBS or Ratheon.

Sylvania 6L6GC / Philips 7581A Same tube?

feeds@yuku.com (Idunknow) — Wed, 04 Feb 2009 14:54:05 GMT

I got some Philips 7581A's on the way for my Rivera amp because Rivera recommends the Philips 7581A or 6L6GC STR Tall bottle Sylvania as the best old style tube for the amp & they act like it's the same tube. I have read that they are the same tube because Philips bought out Sylvania & kept making the tube just under the new name of 7581A instead of 6L6GC STR. Just wondering if they are the same tube or are actually different tubes. If they are the same tube then they would be...

Weber Copper Cap Rectifers?

feeds@yuku.com (GLUGSTER) — Mon, 12 Jan 2009 20:28:57 GMT

Has anyone ever used these:

http://www.webervst.com/ccap.html

Since they are affordable and totally reversible, I thought about dropping one in my '66 Super Reverb. Any thoughts?

GT EL34LS 30W?

feeds@yuku.com (Idunknow) — Sat, 10 Jan 2009 04:56:36 GMT

was wondering if anyone knew whether or not the Groove tube EL34LS is a 25w or 30w tube. I got a set & used 25w to bias them but I saw on Dougs tube site that they are 30W tubes. They sound very good, very surprized.

Tube recomendations from Kittleson

feeds@yuku.com (retrorod) — Fri, 09 Jan 2009 08:49:00 GMT

I just read an interesting article from Vintage Guitar mag. Just wanted to pass along these favorite tube recommendations,FWIW, from Charles Kittleson, the GURU of Vacuum Tube Valley. The following are his favs of 'current production'.

-12AX7-
-JJECC803
-JJECC83S
-E-H 12AX7EH
-Sovtek 12AX7LP

-6V6-
-New Sensor 6V6GTA(tung-sol re-issue)
-JJ6V6GTS

-6L6-
-TAD6L6WGC
-WingedC SV6L6GC or SED
-re-issue Tung-Sol...

Tech Tube Valves

feeds@yuku.com (KHAN) — Sun, 28 Dec 2008 17:51:49 GMT

Not sure what to think of this. Maybe building them on hallowed ground will bring some mojo.

http://www.techtubevalves.com/

A really cool vintage film here on the Blackburn factory:

http://www.techtubevalves...m/about_us/film_reels.php

Suggested EL84 brand?

feeds@yuku.com (retrorod) — Tue, 23 Dec 2008 18:41:04 GMT

What is the suggested brand of EL84 tubes for Blues Jr ? I have read that factory bias on these amps is on the hot side, Therefore, BillM's mods. I just got one in for fix-up. Looks to have the original tubes...Fender branded GT's. Thanks for advice, Rod

Groove Tube 6L6CHP ?

feeds@yuku.com (retrorod) — Mon, 22 Dec 2008 06:18:05 GMT

Gotta question. Got a Twin Reverb in for checkup/bias. Customer had already bought a new quartet of GT6L6CHP (black plate) aka;5881...all of this printed on the tube..ha. I have adjusted bias and was double-checking this morn and in the dark test noticed a blue ring(top and bottom) on each of the tubes. Is this normal for these tubes?....or should I be suspect for something else? Thanks, Rod

KT66 Instead Of 6L6

feeds@yuku.com (Jammin John) — Tue, 16 Dec 2008 10:13:38 GMT

I am running KT66's in a Low Powered Tweed Twin and in a Tweed Pro.
I am aware that they draw more heater current and they require a rebias but is there anything else I should do to safely run them ?
They sound great !

JJ