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Marvel 35 tube amp

Discussion in 'Musical Instruments' started by Lazarus Long, Sep 5, 2018.

  1. Lazarus Long

    Lazarus Long Super Member

    Messages:
    1,762
    Location:
    Michigan
    I picked up a Marvel 35 amp today. It appears to be all original. Cosmetically it is pretty rough, but if it actually works, ill build a new cabinet for it.. What should I do to test this thing before I plug it in and blow something up?
     

     

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  2. Binkman

    Binkman AK Subscriber Subscriber

    Messages:
    6,555
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    Chapel Hill, NC
    did you get an answer? or did you blow something? (or dead?) dealing with high v's on most tubes.
     
  3. Lazarus Long

    Lazarus Long Super Member

    Messages:
    1,762
    Location:
    Michigan
    Nope... Its still just sitting there, taunting me.
     
  4. dr*audio

    dr*audio Fish fingers and custard! Subscriber

    Messages:
    18,745
    Location:
    Cleveland, Ohio
    Do not turn it on. This thing is really old and the coupling caps going to the grids of the output tubes must be replaced. I would also test the power supply caps for leakage with a cap tester that can apply full power supply voltage to them.
     
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  5. Lazarus Long

    Lazarus Long Super Member

    Messages:
    1,762
    Location:
    Michigan
    Photo of the guts.. 3 of the yellow capacitors are 600 wvdc, one is 200... The blue one is marked, Mallory .033 600 vdc

    Easy enough to replace those.. But, what do i replace them with?
     

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  6. nj pheonix

    nj pheonix AK Subscriber Subscriber

    Messages:
    9,930
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    New Jersey
    Not too much to that. I suspect it wont put up much of a fight.
     

     

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  7. Lazarus Long

    Lazarus Long Super Member

    Messages:
    1,762
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    Yeah, its pretty damn simple. Another pic..
     

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  8. dr*audio

    dr*audio Fish fingers and custard! Subscriber

    Messages:
    18,745
    Location:
    Cleveland, Ohio
    Go to Digikey.com. Search for polyester capacitor. Limit the search to "in stock." Then look at the drop down boxes and select "through hole" and "Axial"
    After that you can pick the capacitance first, then the voltage. Same capacitance, same or greater voltage. Any polyester film cap will be fine. Buy the cheapest ones. Epcos makes good ones that are cheap, as does Panasonic.
     
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  9. JohnMac

    JohnMac Addicted Member

    Messages:
    5,271
    Location:
    Front Range, Colorado
    Cool amp. Is the cabinet really that bad? It would be nice to keep it original if possible.
     
  10. Lazarus Long

    Lazarus Long Super Member

    Messages:
    1,762
    Location:
    Michigan
    Yes the cabinet is that bad.
     

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