help for '61 Ampeg Reverberocket?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by hawkeyeinexile, May 22, 2006.


  1. hawkeyeinexile

    hawkeyeinexile Silver Supporting Member

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    well, the little sweetheart is still sick. sounds like a 60Hz buzz. pulling the back panel & tapping all around w/chopsticks seems to point to the power supply area at the right side (looking from the rear). tubes (some more than once), caps & cap can have been replaced, everything else in that "power" section has been re-soldered nicely. thought it was fixed, but the buzz is back.

    any recommendations where i can send this thing for a cure?

    thanks in advance,
    :cool:
     
  2. brad347

    brad347 Member

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    re-tension those tube sockets! Does it have a tube rectifier? If so, has it been replaced? If not, have you checked the diodes?
     
  3. slider313

    slider313 Silver Supporting Member

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    Does it sound more like a ground buzz? I believe early Ampegs all have some hum until you plug an instrument in because of the non shorting input jacks. Does the hum continue after plugging in?
     
  4. AL30

    AL30 Member

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    Death cap removed?

    I have a '66 Gemini 1 with non-shorting jacks and it does hum a little like slider313 mentioned.

    AL
     
  5. hawkeyeinexile

    hawkeyeinexile Silver Supporting Member

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    it has been exhaustively checked by our local amp tech, much replaced, cold solders found & corrected, etc.

    yes, they hum some before plugging in, but this buzz comes on after a few minutes of playing. at first intermittently, disappears after giving it a little slap on the top, then comes back & stays on - is louder than the notes being played. the effect can be reproduced by pulling the back panel & tapping around right side of the board (where the cap can, etc. are). tube sockets appear to be fine.

    :cool:
     
  6. JimiB

    JimiB Member

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    sounds like a cold solder joint or an intermitent tube. does your tech have a scope? does the buzz keep on if you pull the first preamp tube? if so keep pulling preamp tubes in order to see if it stops at some point. if it does stop at some point try replacing that tube. if you can't fix it or get it fixed send me an email.
     
  7. slider313

    slider313 Silver Supporting Member

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    Make sure the foil insulation on the back panel is not worn to the point of it not making contact. A ground problem or cold solder joint would cause this for sure.
     
  8. donnyjaguar

    donnyjaguar Member

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    My only advice is that most problems with tube amps that cause this radical of a change in character can usually be nailed down by checking the operating voltages throughout the amp itself. If the schematic doesn't have the voltages on it then you'll have to roughly calculate them. I'm guessing you'll find one that is wildly off and this will help you nail it down. If you're not comfortable working with these high voltages, or are unsure of the capability of your test instruments, I'd find someone who is.
     

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