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amp noise with Quad 909-help needed

I have a new Quad 909 SS power amp. It is great to look at...but makes audible hum plus some FM radio noise, even when no premp or source component is connected to it. It has a two-prong IEC inlet, so I guess I cannot even try the cheater plug. I tried different power outlets, and conditioners at home, none gets rid of this hum. I also tried different power cords. I have two tube integrated amps, they are both much more quiet, even on 95db speakers! Any experience on common sources of hum in SS amps, or specifically Quad 909? ,and what to try next? Thanks in advance for any suggestions.
mercurypdx
fire_bottle
19 posts
 
I wish I could be of help here, but I don't have any ideas. I can tell you that my two 909s have always been dead quiet, and I've had them in systems raging from home theater to complex two channel systems. I would suggest either returning it or taking it in for possible repair.
bob_bundus
1,834 posts
 
The two conductor line cord suggests there's no ground. Perhaps try grounding the chassis with a separate wire?
Also try reversing the AC line polarity.
This last idea seems radical & shouldn't be necessary, but perhaps try a line isolation transformer?
mercurypdx OP
16 posts
 
Is a line isolation transformer different than those in power conditioners? Reversing polarity did not help. I will try the chassis grounding. Thanks for the replies.
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