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Carver PM900 power amp with hum/buzz

I have a Carver PM900 power amp with what sounds like a ground hum/buzz in both channels. My repairman here in Atlanta can't figure it out after two hours of scoping and manual/schematic research. The best he can come up with is that it may be some kind of power supply issue. any suggestions? Thanks, Jerome.

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1-shut down all flourecent lamp and check.
2-check for your cables in a good condition and no touching of wires to the body of amp.
3-connect(ground loop isolator)code number(270-054)from radio shack near you and connect it between your audio device(like cd player and amp)

Posted on Apr 15, 2009

  • Jonathan Ansell Dec 08, 2010

    The buzzing is inherent in the design of the PM range. It is due to the triac in the power supply.
    You may wish to try replacing or improving the passive snubber network around the triac.
    Personally, i prefer to add a large mains filter (similar to those found in washing machines) to the mains cable.



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