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Preamp Woes 8080 H(Valvestate 80V)

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  • #1

    Preamp Woes 8080 H(Valvestate 80V)

    Hi I have a Valvestate 80V that I am repairing for a friend. The clean chanel sounds fine but there is a volume drop on the od1 and 2 channels and the crunch is around the same as the clean.

    All the caps look good and the resisotrs etc all test out...

    IC9 and IC10 are both hot but I think this may be a sytomp rather than the problem, the rails were reading around 15.5v here so seems fine. I am going to replace the IC's anyway as this had a new volume pot fitted by a dealer who looks to have made a hash of rewiring the reverb unit so best to be safe than sorry.

    Does anyone else have any suggetstions? Not cables or connectors as I have checked here.

    Thanks...
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  • #2
    Since someone has screwed around with the reverb circuit I would bet that's what blew those IC's. Typically there should be no DC on pins 1 and 7 of OpAmps unless it's part of a floating ground. Also I would double check the value of the volume pot that was installed.

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    • #3
      Hi I have replaced IC 9 and 10 but OD1 is still noticeably quieter than the clean and even OD 2 Channel.

      Does anyone have any suggestions?

      Cheers

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