Tung Sol Reissue 12AX7 not for CF stage !!!

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novosibir
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Tung Sol Reissue 12AX7 not for CF stage !!!

Post by novosibir » Sat Jul 19, 2008 4:35 pm

Although I've already had some bad experiences a while ago with the Tung Sol Reissue 12AX7 (and also the Sovtek 12AX7LPS), when putting it in CF stages, I recently buyed some again - hoping, that they became better meanwhile. But unfortunately I was mistaken :evil:

This week I got a VOX AC 15 for service and supplied all preamp stages with Tung Sol's. Only after 10 seconds (in Words: AFTER TEN SECONDS) playing the amp the CF tube died.

Ok, pulled it out and stuck another TungSol in this spot - this 2-nd one died immediately WITHIN THE FIRST SECOND of operation :twisted:

Ok, tubes in the CF stage of a VOX are under higher stress than in a Marshall CF stage, because due to the 56K cathode R there's more current through the tube, than in a Marshall with a 100K cathode R - but...

... the previous (Chinese 12AX7) tube in this spot was working flawlessly there 12 years :wink:

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Re: Tung Sol Reissue 12AX7 not for CF stage !!!

Post by 5150loveeddie » Wed Jul 23, 2008 8:44 pm

novosibir wrote:Although I've already had some bad experiences a while ago with the Tung Sol Reissue 12AX7 (and also the Sovtek 12AX7LPS), when putting it in CF stages, I recently buyed some again - hoping, that they became better meanwhile. But unfortunately I was mistaken :evil:

This week I got a VOX AC 15 for service and supplied all preamp stages with Tung Sol's. Only after 10 seconds (in Words: AFTER TEN SECONDS) playing the amp the CF tube died.

Ok, pulled it out and stuck another TungSol in this spot - this 2-nd one died immediately WITHIN THE FIRST SECOND of operation :twisted:

Ok, tubes in the CF stage of a VOX are under higher stress than in a Marshall CF stage, because due to the 56K cathode R there's more current through the tube, than in a Marshall with a 100K cathode R - but...

... the previous (Chinese 12AX7) tube in this spot was working flawlessly there 12 years :wink:

Larry
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Post by joshwilson3 » Thu Jul 24, 2008 1:52 am

What is a CF stage?

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Post by thousandshirts » Thu Jul 24, 2008 2:47 am

It's top secret code for cathode follower stage Josh. How's that amp coming? :lol:

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Post by joshwilson3 » Thu Jul 24, 2008 12:48 pm

thousandshirts wrote:It's top secret code for cathode follower stage Josh. How's that amp coming? :lol:
From reading other threads, I'm guessing that is V2?

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Post by thousandshirts » Thu Jul 24, 2008 7:18 pm

joshwilson3 wrote: From reading other threads, I'm guessing that is V2?
The V2 cathode follower driving the tone stack hit it big and got popular with the '5F6' Tweed Bassman. This was copied by Marshall to the JTM 45, where it survived through to the Plexi and Metal Panel amps, and JCM 800, as well. But not all guitar amps have cathode follower stages, and not all of them that do are V2.

For classic Marshalls though, don't put these tubes in V2.

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Post by jbzoso2002 » Sat Jul 26, 2008 2:36 pm

what is the prefered current manufacture 12ax7 for v2 in a classic marshall ??


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Post by LivewireBlanco » Tue Aug 05, 2008 6:29 pm

I have a Tungsol RI in my JTM45 V2. It's been there since April and has seen a few gigs and many practices...
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Post by HARLEYIII » Tue Aug 05, 2008 11:55 pm

I must have got ahold of a good batch of the Tung Sol re-issues. Ive been using them for a couple of years. Have used them in both of my '80 2203's, my 79 superbass, my hacked up 1959 reissue, and my metro 68 12xxx. No problems at all with them.
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Post by Kapo_Polenton » Fri Aug 29, 2008 9:51 am

Hey guys, bringin gback this thread.. I wonder if you guys can help me diagnose an issue i am having with my 1987x clone. I have the tung sols in V1 nd V2 and have swapped them out one at a time for a no name chinese with no difference. balnced JJ in phase inverter. What i've got is ugly distortion when i bend notes in unison.. if i play a D chord for example and strum heavier, a raspy thin distorion comes through almost like it is out of phase. Is this a preamp issue? Do you guys need some soundclips to help diagnose? Its brutal..

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Post by Tuco » Sat Aug 30, 2008 5:44 pm

I've had TungSol reissues in my Metro JTM45 for a year and in my Metro JMP50 for about six months without problems. I buy from Lord Valve, who reportedly test hits them pretty hard to weed out the chaff. (Just don't talk politics with him. :wink: )

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tung-sols

Post by lifer » Sun Aug 31, 2008 7:01 pm

good experience here also----------

used at least a dozen......no prob.

any mass production item is prone to the occassional "f"-up ! :lol:

BTW- Lord Valve......is he "right" or "left" in the political sprectrum??

just curious!

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Re: tung-sols

Post by Tuco » Mon Sep 01, 2008 11:36 pm

lifer wrote:good experience here also----------

used at least a dozen......no prob.

any mass production item is prone to the occassional "f"-up ! :lol:

BTW- Lord Valve......is he "right" or "left" in the political sprectrum??

just curious!
I'm not sure I can see that far to the right. :shock: :lol:

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12ax7 tung sol

Post by lifer » Tue Sep 02, 2008 12:55 am

:lol:

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Re: Tung Sol Reissue 12AX7 not for CF stage !!!

Post by rockford » Thu Sep 18, 2008 8:35 pm

I have one I've been rotating in amps for about a year, no problem. sounds good, maybe a little compressed but very fat and juicy, more than almost any tube i have, even NOS mullard. This Tung Sol reissue really sounds good in the pi slot, and gives the amp a great feel.

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