This posting isn't intended to provoke hundreds of responses. Rather, I'm looking for insights I've missed, that might be of use to both me and others.
Everything in my main audio system _except_ the power amps are on the same circuit. This hasn't caused problems, because the audio connections to the power amps are balanced.
When I added a Sony BDP-550 Blu-ray player to the audio system (its analog audio outputs feeding a Parasound C2 controller), plus a Pioneer plasma TV on another AC circuit (or at least an outlet some distance away), I started hearing a buzz in the speakers at "ordinary" gain levels. It was particularly noticeable in the rear speakers when there was no audio signal to mask them.
The first thing I did was to put the Blu-ray player on an isolation transformer (that just happened to be lying around). That helped, but didn't reduce the buzz as much as I would have liked.
For cable reception, the Pioneer plasma is fed from a Motorola decoder box through an HDMI cable. Disconnecting the decoder from AC, and the HDMI from the Pioneer plasma further reduces the buzz.
It's worth noting that, as you turn up the controller's volume to check the buzz level, the buzz comes in abruptly at one point. Then, to get rid of the hum, you have to turn the volume well below that point. This might be a psychoacoustic illusion, but I doubt it. It seems more like some weird sort of hysteresis. Is it a symptom that points to a cause?
It should come as no surprise that the only way to really suppress the buzz is to disconnect the HDMI cable that connects the Blu-ray player to the Pioneer plasma. Of course, you can't do that when watching Blu-ray movies!
It would be nice if I could simply leave everything connected all the time. I've thought of connecting the plasma's AC to the main audio system's power outlet with a very heavy (12ga) cord. But I'm not sure I want to add 400+ watts load to that outlet. *
Thoughts, please. Thank you.
- Even with the controller and several other components running, I'm drawing less than 300 watts, so there's "room".