Help, my Sherwood Newcastle AM-9080 amp buzzes

Discussion in 'Archived Threads 2001-2004' started by sarat, Jan 10, 2002.

  1. sarat

    sarat Auditioning

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    I bought a new Sherwood Newcastle AM9080 amp in an auction after reading good reviews for it on AudioReview.com. I have this amp paired up with Magnepan 1.6 QR fronts,

    Infinity surrounds and a Harman Kardon AVR 310 receiver (acting as preamp).

    I am very dissappointed with this amp. With the Receiver turned off and only the amp turned on, my speakers keep buzzing and the sound is irritating. The buzzing is worser on the smaller infinitys. The buzzing remains even when playing audio sources, but, obviously less apparent. When listening to CDs in stereo mode, I have to disconnect the surrounds as the buzzing is intolerable.

    I don't know why this is happening, as there is no signal

    going to the amp. I tried connecting the amp to a Monster Power conditioner, but the buzzing is still there. The power conditioner has a ground loop light which is on, so I am guessing the unit is properly grounded.

    Anybody else notice similar buzzing with their amps or is mine a defective one? Any suggestions or tweaks to fix this?

    This is my first step into separates and am feeling like going back to Receivers. I had an Onkyo receiver before which was dead silent @ full volume with no source. Do all amps do this?

    Please help. Thanks.

    -Sarat
     
  2. Evan S

    Evan S Cinematographer

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    I can't answer much of you inquiry except to say that my Anthem Amp is totally dead silent, either in standby mode or when activated with a source. Don't know what to tell you there. Sounds like a grounding problem (dispite the readout from your Monster), or otherwise I would say you have a defective unit.
     
  3. Jay H

    Jay H Producer

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    Sounds to me you have a ground loop problem. Don't think that your amp is bad or defective, just you happen to have a ground loop problem.

    Possible solutions:

    Try to plug in all your devices into one power strip/outlet.

    Try to see if there's another culprit for the hum, lights, refridgerators, etc, in your house/apt on the same circuit. It might require some homework with the circuitry here. If so, perhaps try to plug the Monster Powerstrip into a different circuit/output.

    Get one of those ground loop circuit buster things. Can't recommend anything but I think you can probably find it by searching the old Hardware forums for "ground loop".

    Last resort or if you want to diagnose it as a ground loop, get a 3-to-2 prong converter and put that on the plug of your Sherwood and plug that into the Monster power strip. if the hum goes away, then you know it's a ground loop problem. Yeah, you can fix it by leaving the amp ungrounded but most people would recommend against this cause now you are at risk for electrocution if something major goes wrong with the amp and the unit is now not grounded to earth (except through you).

    Jay
     
  4. sarat

    sarat Auditioning

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    Thanks for the suggestions. Yes, it turned out to be a Ground Loop issue. I connected the 3 pin plug to a elcheapo 2 pin adapter and the buzzing was gone [​IMG]. I am worried about this setup though, as I have no grounding for my amp now and any sudden surges in power will probably destroy my amp.
    Is there any other way to ground the amp? There is a little screw at the back of this amp for separate grounding.
    Thanks,
    -Sarat
     
  5. Legairre

    Legairre Supporting Actor

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