Need to find capacitor for my preamp.

Discussion in 'Community Discussion' started by velocityg4, Jul 17, 2015.

  1. velocityg4 macrumors 68040


    Dec 19, 2004
    I'm trying to find this specialty audio grade capacitor for my venerable Yamaha Pre-Amp (C-80 as I recall). When in use for an hour or so audio in the right channel will get static or cut out. I've gone over everything on the board. I can't find any cracked solder joints. The pots all seem fine. All I could find were these two slightly bulged capacitors. So I think they are the problem.

    The problem is I can find ones which match their voltage and uf ratings. But they are all two pin and appear to be rather small. While the capacitors I need are four pin and rather large.

    One side reads Nippon Chemi-Con. Audio Neg. Black 85 (degree symbol) C. It appears the part number on top is 58GAH. They are rated (B) 35v4700uf(M), (A)(C) Blank, (-).

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  2. D.T. macrumors 604


    Sep 15, 2011
    Vilano Beach, FL
    Check out, that's where I score my caps, they carry a _huge_ assortment, possibly some high grade like you're wanting.
  3. chown33, Jul 17, 2015
    Last edited: Jul 17, 2015

    chown33 macrumors 604

    Aug 9, 2009
    Also try for caps.

    Here's the manufacturer of the existing caps:

    Search their site to find their US distributors.

    Crackling in the output can also be caused by a failing transistor. Basically, it malfunctions when it gets warm.

    It might be a power transistor in the output stage, or one of the small-signal transistors earlier in the amp channel. There might be no visible indication that the transistor is bad. Some freeze-spray may help find it, or it may not.

    Without a schematic and some way to look at signals in the channel (e.g. oscilloscope), you'd probably have to take it to a repair shop.

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