Lafayette (or Univox??) U-80A mystery amp

Discussion in 'Amps and Cabs' started by jrcstudios, Dec 19, 2009.


  1. jrcstudios

    jrcstudios Member

    Messages:
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    Dec 19, 2009
    Location:
    Thomasville, Ga
    I am re-building this amp for a friend. Upon power up, one of the power tube's plate glows red after less than a minute, and the output is terribly distorted and reeks of 60 Hz hum. The capacitors are oil filled.. or at least they were!

    The entire chassis was covered and almost dripping of an oily substance. I washed it so I wouldn't get it all over me while handling, and now some of the resistor's color codes are gone.

    It is a "Muscal Amplifier" that's right no "i" Searching online, I found this was a Japanese-Univox thing? can't find an "80" model though.

    It uses 12AX7's for preamps and 6AQ5's for power tubes. Solid state rectifiers.

    I've ordered all new capacitors, if that's all it takes to fix it, I will be in good shape, but would love a schematic to be able to troubleshoot with.

    Schematic, anyone?? Please?!?!

    Pictures:
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    Transformers were removed before washing.... I do have them...

    [​IMG]
     
    Last edited: Dec 19, 2009
  2. nmiller

    nmiller Drowning in lap steels Silver Supporting Member

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    Location:
    Rocky Hill, CT
    Built by Unicord (maker of Univox) in Westbury, NY. Mid-1960s, based on the solid-state rectifier. There was probably a U-80A Univox model as well, and if you're looking for a schematic I'd look for a Univox-labeled one. That amp will sound amazing if you can get it to work - all '60s Univoxes do. They did wonderful things with 6AQ5s.
     
  3. jrcstudios

    jrcstudios Member

    Messages:
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    Joined:
    Dec 19, 2009
    Location:
    Thomasville, Ga
    oops, yes, by Vox in my post I meant Univox (big difference!) I'll edit my title to fix that.

    I had been on that site already and could not find a U-80 listed.. maybe they called it something else? I'll keep digging. And thanks for your last comment, I'm glad to know I'm not working on a terd..

    --John
     

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