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.
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.