So what would happen...

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by webs, Oct 5, 2006.

  1. webs

    webs Supporting Member

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    ...If I put a 12AT7 without matched sections in the trem spot of a DRRI? The tremolo is shot and I have an AT lying around but I don't know if it's matched or not. Is it ok to throw it in to see if it will work?

    Also, I can't for the life of me find a schematic of this amp. Anybody want to hook a brother up? At least a tube diagram....anything...:AOK
     
  2. brad347

    brad347 Member

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    you dont need matched triodes for the trem tube. Only one section is used IIRC and in any case, the tube itself is not in the audio path at all, it is only an oscillator. It's the best place for your cheapest, most microphonic, worst sounding tube. An AT7 would probably work fine and definitely wouldn't hurt anything.
     
  3. webs

    webs Supporting Member

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    Great, thanks! Is it the reverb driver that needs to be matched then? I'm new to this kind of thing.

    One more- Would an AX be ok in the trem spot?
     
  4. brad347

    brad347 Member

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    yes an AX would be fine in the trem spot. I think that's the stock tube for that location. The reverb driver doesn't have to have matched triodes. In fact, none of the tubes "have" to have matched triodes.

    Some people like to get matched triodes for their phase inverter tube. I don't. I like the sound of a regular old "maybe mismatched a little" tube just fine.
     
  5. webs

    webs Supporting Member

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    Excellent, thanks so much.
     
  6. tonezoneonline

    tonezoneonline Member

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    All good advice.If you can't find a schematic for your amp at www.mrgearhead.com email me and I'll send you one.
     
  7. brad347

    brad347 Member

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    This is my reasoning too but I wasn't going to go into it. Too lazy. Thanks! :AOK

    it's also why I think rigidly matched power tubes are semi-futile as well. Sure you can get closer and maybe notice something but with a long-tailed pair phase inverter that isn't balanced anyway, in order to get anything totally balanced it would be really hard work of testing both triodes of a tube and selecting 12AT7s for specific values/current draw in each triode, etc.

    And you know what? That would maybe get it sounding a lil' more 'hi-fi' if you could tell at all, and it would probably sound LESS like a guitar amp that you want to hear. As long as the tubes are matched close enough to spec that they're not humming or creating a really unbalanced situation then you're fine. Within 10% is probably fine.
     
  8. rockon1

    rockon1 Member

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    Matched pre amp tubes are unnecessary in any slot-PI included. Save your money! : > )
     
  9. Chris Scott

    Chris Scott Silver Supporting Member

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    Here's an idea for you--

    Play a bunch of tube amps.

    Make that Fender amps, maybe even tweed, just for kicks.

    Keep playin' them 'til you find the one that just knocks you into the cheap seats with "the tone".

    Take out the tubes, and give 'em to that guy that can properly measure them (especially to see how well they're "matched")

    What did he tell you?

    Don't be shocked--it's only magic!

    While you're at it, go and find a nice and microphonic 12A-7 and throw into the V-1 slot.

    Whoa! -got that one while watching Roy Buchanan at the Troub one night years ago-- he could barely keep the thing in check. But you could tell-- there was something goin' on there.......
     
  10. brad347

    brad347 Member

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    MICROPHONIC PREAMP TUBES RULE

    and i'm not kidding.

    Heaven was when I found a pretty microphonic old Amperex to put in v1 of my 6G4-A super. Heaven.
     

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