60Hz hum from speaker with no input
this thing has been bugging for for a while now. I have searched so many places, and it keeps talking about "AC ground loop" ... which doesn't seem to be the problem I have. I hear a 60Hz hum on both speakers.
AC plug ---> Parasound A21 ---> speaker
The Amp is resting on a glass panel, only electrical wire connected to Amp are (a) AC power and (b) wires to the speaker.
It might be something wrong with the AC connections in this OLd house, but not able to figure out what.
Here are other facts,
- I tried connecting 2-prong power, didn't help
- I tried connecting to different AC outlet in different rooms, same problem
- I tried connecting different speakers, same result
- I have 2 brands of sub-woofer, even they hum with or w/o any input connected
- I have hum coming out of Marantz Sr5012, as well as Denon AVRX3400h
it seems that my house is *** haunted ***, can somebody point me to possible problem and solution ... thanks