FDP Forum / Help identifying a tube/ 18 messages in thread.

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Guitar Fool

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Sunshine State

Just a pawn in someone else's game
Dec 19th, 2017 07:19 PM        

I have a pre amp tube that I believe to be a 12AX7...but the lettering is worn off...<br /> <br /> I've tried using a flash light, I've tried to fog it up by breathing on it, and even placed it in the freezer for a short time so that the condensation on it might help show up the lettering...nothing..<br /> <br /> I put it in an amp and it certainly works....is there another method that will make it possible to see the lettering on it?..<br /> <br /> since I know it works and it's probably not as big a deal as I'm making out of it, I'm curious if there is a better way of determining this in the future if I happen to run into it again...



Peegoo

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Dec 19th, 2017 08:54 PM        

Some close-up pics of the internal structure--especially the metal can in the middle, and what's in the top of the tube.<br /> <br /> Snap a few and post 'em here, and we can probably figure it out.



Pinetree

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NW Pennsylvania

Dec 19th, 2017 09:52 PM        

What amp did it come from?<br /> <br />



Guitar Fool

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Sunshine State

Just a pawn in someone else's game
Dec 20th, 2017 09:07 AM        

Hard to say what amp it came from ..I've been accumulating tubes for some time...I'm guessing I have around 30 12ax7's not in amps an maybe close to 10 in amps...I got a bunch out of a Baldwin organ..I believe them to be Sylvania but labeled as Baldwin..the lady that used to live 3 houses down, her husband was a TV repair guy and he passed away... She gave me a bunch of tubes and a tube tester...major score!<br /> <br /> I've compared the tube to the others I have and certainly looks similar...I tested it and the reading is consistent with a 12AX7...<br /> I took some pics and post them in a couple of minutes



Guitar Fool

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Sunshine State

Just a pawn in someone else's game
Dec 20th, 2017 09:27 AM        

here's the whole lot minus those in my amps



Guitar Fool

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Sunshine State

Just a pawn in someone else's game
Dec 20th, 2017 09:28 AM        

another pic



Guitar Fool

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Sunshine State

Just a pawn in someone else's game
Dec 20th, 2017 09:29 AM        

last but not least



Peegoo

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Curled up

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Dec 20th, 2017 09:53 AM        

Hmmm...small halo getter and short plate with two narrow stake holes on the flange. Looks like a Siemens or perhaps a Telefunken.<br /> <br /> But I think it's an Amperex ECC83; not certain tho.<br /> <br /> More pics of different side views would help.



Peegoo

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Dec 20th, 2017 10:05 AM        

Here's a pic of a late-60s/early 70s Amperex 12AX7-ECC83, stamped HAMMOND for the organ company of the same name. <br /> <br /> Compare what you have there with the details in this pic.<br /> <br /> Amperex (Holland) made tons of these for radios, hi-fis, organs, militaries, and medical devices. Many were re-branded under production contracts. And some escaped the factory with no markings on 'em.



Guitar Fool

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Sunshine State

Just a pawn in someone else's game
Dec 20th, 2017 12:48 PM        

tks for the help...I think your in the right territory... definitely European...I pulled out all my 12ax7's and compared them to this one to look for consistency in the getter, and plate. etc,...and I found a match...but the lettering is worn off as well but I can read ECC and I know that's the European designation..<br /> <br /> I'm inclined to think its German..either Telefunken or Seimens as you say... I had a bunch of Amperex 12AU7 that I sold and it doens't look quite like that..the only other possibility would be a Mullard....<br /> <br /> since it works and all I'm going to let it go at this point....it would be nice to know though....<br /> <br /> I'm curious if anyone has a different method of determining the writing on the tube when its worn off....<br /> <br /> this has been fun!<br /> <br />



rfrakes331K

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IL USA

RonHalen Jokingly He Says
Dec 24th, 2017 06:38 AM        

Have you tried Black Light.



Guitar Fool

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Sunshine State

Just a pawn in someone else's game
Dec 24th, 2017 07:29 AM        

no...but it sounds like a good idea....have you tried it or suggesting it?



Elmo66

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Midwest USA

Dec 26th, 2017 04:35 PM        

Telefunkens will have a diamond shape on the bottom of the tube between the the pins. No diamond, not a Telefunken.



Elmo66

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Midwest USA

Dec 26th, 2017 04:49 PM        

Mullard/Amperex tubes will "flash" the first side heaters upon a cold start. Take a look when you fire it up.



Guitar Fool

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Sunshine State

Just a pawn in someone else's game
Dec 26th, 2017 06:39 PM        

thanks for the great info....



Guitar Fool

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Sunshine State

Just a pawn in someone else's game
Dec 27th, 2017 07:33 AM        

on of them has a diamond....learn something new every day!<br /> <br /> thanks Elmo!



Peegoo

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Curled up

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Dec 27th, 2017 01:24 PM        

Bam!



Elmo66

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Midwest USA

Dec 27th, 2017 05:46 PM        

In the 1960's, Telefunken was trying to make inroads into the U.S. market by giving away tubes for free to the major stereo manufactuters like Fisher, H.H. Scott, Marantz, and Mcintosh. I have a 1967 Princeton Reverb with original Telefunken's. Leo probably LOVED free tubes. Luckily, they were/still are fantastic tubes. Enjoy!



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