12AT7, which tube position?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by jordiesaenz, Feb 29, 2012.

  1. jordiesaenz

    jordiesaenz Member

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    I need to lower the gain that's on tap with my Blues Deluxe Reissue. It's too loud for the places I play at. I have a 12AT7 tube. Which spot should it go in?
     
  2. phsyconoodler

    phsyconoodler Member

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    The spot closest to the power tubes.You could try it in V1,the furthest away,but it's not really the right tube for that spot.You should have gotten a 5751 or a 12AY7 for that.
    Google or go on E-Bay and find the 'HRD volume control'. You put it in the effects loop and you get control over that touchy volume on those amps.
     
  3. Blue Strat

    Blue Strat Member

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    In the phase inverter, the spot closest to the power tubes, you probably won't hear any difference in volume. V1 would be the spot but you may not like the tone.

    A 12AY7 would probably be a better choice.
     
  4. Timbre Wolf

    Timbre Wolf GoldMember Supporter Gold Supporting Member

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    :agree

    Might even consider using a 12AU7 for V1 (closest to 1/4" input jack) for lower volume. ...Or a much less efficient speaker.

    - Thom
     
  5. guitarcapo

    guitarcapo Senior Member

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    I've heard it said that 12AT7 tubes were never designed for audio amplifying applications. Just functional applications like phase inversion. Something about frequency responses etc. I've used them in V1 or V2 with no problems in sound myself. Usually I'll use a 12AV7 or 12AY7 instead, though. Maybe a 5751 tube....
     
  6. Timbre Wolf

    Timbre Wolf GoldMember Supporter Gold Supporting Member

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    In my opinion, personal experience trumps InterWeb theory every time. Go with what you know.

    - T
     
  7. Blue Strat

    Blue Strat Member

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    Indeed. Try everything that's safe.

    The meme about "never designed for audio applications" is repeated often...by people who don't know Ohm's Law that read it on the web. ;)
     
  8. phsyconoodler

    phsyconoodler Member

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    Get a few and try them out.
     
  9. Heady Jam Fan

    Heady Jam Fan Member

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    I agree with all of the above - people often say an AT7 in V2 is to brittle or harsh, electronically it has many difference from other preamp tubes IIRC, but I don't know what causes the tonal difference. I think the 5751 is close as far as the amount of headroom before it distorts.?. and is consider to be a bit creamier than an AX7. That was SRV's V1 choice. AYs and AUs are other good choices depending on how much you want to drop the volume, maybe try one of each other those along with a 5751.

    The RI has a master volume, but I am assuming you don't really like it? You could have that moved to after the Phase Inverter - I have that and really like it.
     
  10. jordiesaenz

    jordiesaenz Member

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    @ Heady Jam Fan

    The master volume is only for the drive channel, which I never use. I'm a clean channel guy, and I use pedals to do all my dirty stuff, but mostly I'm doing delay/trem/verb stuff for worship in small rooms, or rooms where I don't want to be too loud. I'll just experiment :)
     
  11. Heady Jam Fan

    Heady Jam Fan Member

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    Oh cool, I am not too familiar with the RIs - on my '65 Bassman, I have a master volume on the dirty channel (modded from the bass channel) and the PPIV (post phase inverter volume) that (obviously) effects both channels.

    I have to admit - I have been completely opening up the PPIV lately when playing Jam (so the amp is clean, but 1-2 TS9s), probably pissing off my whole neighborhood. Just sounds/feels so much better (probably power tubes and speaker compressing).
     
  12. ptrickamp222

    ptrickamp222 Member

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    12AT7 is for the phase inverter or reverb. 5751 for V1 or equivelent. Search the net I find what's on sale.
     
  13. jordiesaenz

    jordiesaenz Member

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    So most of you are saying that the phase inverter spot is where I want it. Will that lower the volume/gain significantly?
     
  14. phsyconoodler

    phsyconoodler Member

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    No.Get a 12AY7 or a VOLUME box.

    Go to E-Bay and search HRD volume box.It will solve all you volume woes.
     
  15. Timbre Wolf

    Timbre Wolf GoldMember Supporter Gold Supporting Member

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    Do you have a plausible source document for this 5751-SRV statement? I would love to see it.

    Nothing personal, and I'm not picking on you - you're one amongst many who promote this InterWeb mythology. I'm guessing that you probably don't have the evidence, but I always ask, just in case someone can finally come up with documentation. I've never seen any convincing evidence identifying 1) which position, and 2) which 5751 SRV preferred. There are lots of different 5751, and I wouldn't call them creamy, from my personal experience.

    - Thom
     
  16. Nickstrtcstr

    Nickstrtcstr Lactose Intolerant Guitar Slinger

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    I put a 12AT7 in the V-2 of my Hot Rod Deluxe. I have a 12AX7M in the V1. It eliminated the buzziness that was inherent in the amp. So from my experience the V2 was the magic spot. YMMV.
     
  17. phsyconoodler

    phsyconoodler Member

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    thats only for the distortion channel.Useless for clean as the OP was asking.

    GET A VOLUME BOX !!!!
     
  18. Nickstrtcstr

    Nickstrtcstr Lactose Intolerant Guitar Slinger

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    You might want to re-read the OP here:

    jordiesaenz [​IMG]
    Supporting Member
    Join Date: Oct 2011
    Posts: 64


    12AT7, which tube position?
    I need to lower the gain that's on tap with my Blues Deluxe Reissue. It's too loud for the places I play at. I have a 12AT7 tube. Which spot should it go in?
    __________________
    Good deals with:
    Jesus freak, JWALKER, vanguard, fugot,
     
  19. Heady Jam Fan

    Heady Jam Fan Member

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    I have read that many times in the past, maybe it is internet myth, but nearly all 'evidence' stated on forums (if not all) is internet myth, right? We are on the inter-webs?

    I definitely don't remember were I read that, I thought it was common knowledge, but certainly could be wrong. For me to find the source would probably be the same process as anyone else doing an exhaustive search and I'm to exhausted.

    Maybe tomorrow I will have the energy to look, but then my source would probably be a website (still an internet source). But that has me wondering if I ever read it in any old guitar magazines... and if they are still sitting in my parents house from 12 years ago.
     
  20. zenas

    zenas Member

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    My take on preamp tubes is this.
    Stick whatever you have (thats safe for the amp) into whatever spot and see how it sounds.
     

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