How to balance Plexi clone while working on it?

Discussion in 'Shock Brother's DIY Amps' started by itsGiusto, Jul 9, 2020.

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  1. itsGiusto

    itsGiusto Tele-Meister

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    I'm still debugging what I think is parasitic oscillation causing weird fizzy swirly distortion in my Ceriatone Plexi clone (without much luck). I need to have the board in the chassis exposed while working on it so I can do things like take voltages, listen to the audio at various points, and use an oscilloscope to probe the signal.

    I can rest it upside down so that it's balanced on the transformers and EL34s, but the EL34s get so hot that I'm not it's safe to rest it on most surfaces - things could burn or melt.

    How do people manage this? Is there anything safe I can rest the amp on upside down?
     
  2. Wayne Alexander

    Wayne Alexander Friend of Leo's Silver Supporter

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  3. Peegoo

    Peegoo Friend of Leo's

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    In a pinch you can empty a small deep dresser drawer, place it on the workbench, and set the hangy-downy bits of the amp into the drawer with the amplificator's chassis supported on each end by the drawer sides.

    Necessity is the mother of amplification, I always say.
     
  4. Ten Over

    Ten Over Tele-Holic

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    I just take some of those books my girlfriend bought and put them under the transformers so that the power tubes are dangling in free air. If I'm going to do anything that is very involved, I put the amp in a cradle that I made for just a few bucks.
     
  5. itsGiusto

    itsGiusto Tele-Meister

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    Cool. I didn't do this exactly because I don't have the right size drawer. But I instead propped it up with two small drawers, one on either end.
     
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  6. Peegoo

    Peegoo Friend of Leo's

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    iMuy excelente!
     
  7. jtcnj

    jtcnj Tele-Holic

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    2 or 4 short cuts of 2x4 work well for me.
     
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  8. dan40

    dan40 Tele-Afflicted

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    Yep...I use wood blocks of various thicknesses on each end of the chassis to support it high enough that the tubes don't touch. For smaller amp chassis I have some hard foam blocks that I use to support it while working on it.
     
  9. tele_savales

    tele_savales Tele-Holic

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    One end on the coffee table and the other on your 1x12 combo amp
     
  10. rangercaster

    rangercaster Poster Extraordinaire

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    Peegoo is usually correct 99. 999%
    Of the time ...

    But when he's wrong ...

    It could be fatal ....

    Fair warning ...
     
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  11. Peegoo

    Peegoo Friend of Leo's

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    [​IMG]
     
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