Good NOS 12AX7 for PI?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by RobBozic, Jun 4, 2008.

  1. RobBozic

    RobBozic Member

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    Can someone recommend some NOS 12AX7's for the Phase inverter position. I don't want to spend over $40.

    Thanks
    Rob
     
  2. Blue Strat

    Blue Strat Member

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    Try an ANOS GE or Raytheon.
     
  3. RobBozic

    RobBozic Member

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    Thanks Mike, does it matter if it's a long plate, short plate, gray plate etc..?

    Thanks
    Rob
     
  4. Blue Strat

    Blue Strat Member

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    Not at all. There's been some "net myths" circulating about long plates being especially good for PIs but I have no idea where that notion comes from.
     
  5. solitaire

    solitaire Senior Member

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    There's also some myths saying NOS valves are always better than new ones, which isn't exactly true. Unless you're shooting for a particular tone - I guess not since you're open for any suggestions - current prod valves can be nearly as good. Also this is the phase divider which is perhaps one of the least crucial valves in regards to tone.
     
  6. scottl

    scottl Member

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    Could be that they are more prone to microphonics in the preamp stages. Makes the rejects worthwhile to try in the PI.

     
  7. Blue Strat

    Blue Strat Member

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    ...unless you're talking about longevity/reliability when looking at a large sampling (small samples can show anything).

    If you mean "better" in terms of "sounding better", of course they're not always better. That's a subjective issue which means, by definition, that NOTHING is better.
     
    Last edited: Jun 4, 2008
  8. mbratch

    mbratch Member

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    Are you really looking for a 12AX7, or a 12AT7 for a PI? (just double checking)
     
  9. AintNoEddie

    AintNoEddie Member

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    I guess this is one of these sources:

    http://www.guitaramplifierblueprinting.com/files/Phaseinverter.pdf

    I have to admit that I just recently bought an LPS in order to check it's magic PI capabilities :) I don't have to too high expectations, though.
     
  10. Blue Strat

    Blue Strat Member

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    I'm not saying they'd be any worse, just can't imagine why they'd be "better". ;)
     
  11. Timbre Wolf

    Timbre Wolf GoldMember Supporter Gold Supporting Member

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    I'll second that notion! The phase-inverter position is a great place to put that coveted long-plate tube that you can't use in V1, due to microphonics. I have used '50s Mullard long-plate 12AX7s as PI, for just this reason.

    - Thom
     
  12. rockon1

    rockon1 Member

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    Perhaps... Ive recently gone to trying to find the PI tube I think sounds the best before diving into V1,V2,etc. tube roliing. Make the power section happy then move on. Bob
     
  13. RobBozic

    RobBozic Member

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    Both actually. But I've read that the Mullard CV4024 is great for Fender PI, but I also need a 12AX7 as well for another amp. And I'd rather spend the extra $$ for something that's going to last longer than new production tubes, & if it sounds better as well, well that's a bonus!

    Thanks again
    Rob
     

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