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Mechanical buzz coming from the chassis

I have noticed a mechnical vibration causing a low level buzz eminating from the chassis of one of my monoblocks. The buzz is not audible through the system. It is only audible when your ear is close to the amp. Also if I squeeze the chassis the vibration stops.

The amp is a Quicksilver mid-mono with KT88 tubes.

Any ideas on how to solve the problem?
nick_sr
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stonedeaf
101 posts
 
This is a matter of degree - so how close does your ear need to be to hear this ?
yogiboy's avatar
yogiboy
5,464 posts
 
I had the same problem with my Quicksilvers. I called and was told if the amps were on a shelf I should put carpet underneath amps which solved the problem. I bought a set of isoblocks (cork blocks)and put them under the feet of the amps and they work great. I think that should have been mentioned in the owner's manual.
nick_sr OP
263 posts
 
I have the amps sitting on 1/4" thick cork mats. This helps, but regardless the hum is not audible from my listening position.

The other strange thing is that only one amp hums but both amps had relatively loose screws.

Also, soft mats and tightnening screws will eliminate the symptoms but do not address the root cause.
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hifihvn
943 posts
 
Double check your bias also.A tube starting to short can cause this too.If this amp is easy to bias,you can try swapping the tubes between the two amps.If its hard,it may cause a problem that's not there.
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