Reviving an old post:
I have an A52+ Parasound amplifier, and I love it’s sound, but it has started making a hum in channel 1 that is very noticeable from the listening position (accross the room.) Replacing the amp with another amp and the system is dead quiet. The A52+ makes the noise with no inputs connected, just a speaker connected. This noise is still present using a different power outlet.
The Parasound technical support says this: "It sounds like the normal noise floor of the amp. Channel 1 and 2 will have slightly higher noise than 3-5 because of the proximity to the power supply. If your speakers are higher sensitivity than average (above 90db) it will be more noticeable."
I think that is totally unacceptable. Going to take it back and try and get it fixed. It’s still under warrantee. I hope to get a better resolution than "that’s the way it is".