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The Standby Switch has moved to the top of my bad words list

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  • The Standby Switch has moved to the top of my bad words list

    Over the past few months I've read a handful of repair stories that ended up with replacing old, pitted, noisy standby switches. And today I have a new victim on the bench, and again, it's the damn standby switch.

    This amp is a Carvin V3M head. Owner complains of intermittent hum, hissing, bacon frying, pops. This is stuff we normally attribute to failing tubes, cold solder joints, bad grounds, failing plate resistors, etc., etc.

    I powered up this amp, waited ten minutes, and sure enough, the noises started up. I turned all the gain and Master Volume controls to zero. Still the noises persisted. While they were sounding off, I had a chance to wiggle and chopstick everything, and nothing made any difference.

    Then, I flipped the standby switch to standby mode, and WOW, what a exciting noise that was, like a locomotive engine coming to a stop and letting out a cloud of steam.

    My next step was to bypass the standby switch (and this proved to be easy, because Carvin uses fast-on connectors). FIXED! One step, and the problem is solved.

    So, bottom line, when I hear bacon frying or other intermittent and mysterious sounds, I'm eliminating the standby switch as a first suspect.
    --
    I build and repair guitar amps
    http://amps.monkeymatic.com

  • #2
    Everything has its useful life (3-5 years) and even a standby switch.
    It's All Over Now

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    • #3
      This is almost exactly my experience with a bad HT fuse holder that followed a standby switch on a Dr Z just today. All kinds of chaos remedied by a new and better fuse holder on the B+ feed.
      It's weird, because it WAS working fine.....

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      • #4
        The usual place of standby is just plain wrong,as well as it's typical rating,there are better ways to implement it and take the flyback spikes around.
        Usually Carvins used a 47n cap across to tame he spoke,mine still working from the 90s.

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