12ax7 tube issue Faulty or weak tube maybe???

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by jh45gun, Jan 31, 2008.

  1. jh45gun

    jh45gun Member

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    OK here is the issue on my 5e3 build I am going to the amp tech I go to tomorrow to get some more tubes for this amp either a 12ay7 or a 12ax7 depending on what sound I prefer I know the 12ax7 should give more gain. I have two 12ax7s in the amp now and if I switch them from V1 to V2 the one that was in V2 for the half preamp gain stage and half PI starts out loud and then just fades down to nothing. If I put that funky tube in V2 where It was on the old amp chassis (Preamp/PI) the amp works but I am sure I am not getting the gain this amp puts out as it stays pretty clean. I will know more tomorrow when I swap tubes, but my question tonite is is that one tube faulty to do what it does in V1? (Preamp stage) I am guessing there is something screwed up with that tube or at least part of it.
     
  2. Rosewood

    Rosewood Member

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    Just sub it out, it could be bad. Also could be a tube socket problem.
     
  3. jh45gun

    jh45gun Member

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    Doubt it is a tube socket as I tried a 12au7 in there as that is the only extra tube of that type I had on hand with out taking out one out of my Silvertone and since I am going to the tech's tomorrow I did not want to bother and that 12au7 worked in the V1 fine as does the other 12ax7 so it is not the tube socket. Gonna take my guitar and the amp to the techs so we can try tubes in the amp there before I buy them.
     
  4. jh45gun

    jh45gun Member

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    Bought two tubes today one was a 12ax7 for the Preamp/PI stage though I had a 12ax7 I bought this one and kept my other as a spare. The other was a tube That while marked as a 12ax7 has some of the characteristics of a 12ay7 for the V1 spot. These tubes were specially made for Baldwin Organs and have more gain than a standard 12ay7 yet not as hot as some 12ax7s. I tried a 12ay7 and a 12ax7 plus this one and this one sounded the best yet was cheaper than a 12ay7. My 5e3 now sounds like it should with that snarl that you get when it is turned up.
     
  5. Lonely Raven

    Lonely Raven Member

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    Good to know. I'm thinking about building a Deluxe from parts I have, and I've got a few of those Baldwin 12AY7 kicking around.
     

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