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 !!!
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
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
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
Larry
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
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
Larry
The fault almost always is sitting in front of the amp
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- 5150loveeddie
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Re: Tung Sol Reissue 12AX7 not for CF stage !!!
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
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
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
Larry
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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.joshwilson3 wrote: From reading other threads, I'm guessing that is V2?
For classic Marshalls though, don't put these tubes in V2.
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- HARLEYIII
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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.
My Marshalls aint feedin' back....They're Laughin' at your Line-6
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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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tung-sols
good experience here also----------
used at least a dozen......no prob.
any mass production item is prone to the occassional "f"-up !
BTW- Lord Valve......is he "right" or "left" in the political sprectrum??
just curious!
used at least a dozen......no prob.
any mass production item is prone to the occassional "f"-up !
BTW- Lord Valve......is he "right" or "left" in the political sprectrum??
just curious!
- Tuco
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Re: tung-sols
I'm not sure I can see that far to the right.lifer wrote:good experience here also----------
used at least a dozen......no prob.
any mass production item is prone to the occassional "f"-up !
BTW- Lord Valve......is he "right" or "left" in the political sprectrum??
just curious!
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Re: Tung Sol Reissue 12AX7 not for CF stage !!!
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.