Bring the unit to another location and give it a whirl - I had something similar happen with a Mesa Boogie Dual Rectifier 4x10 "Blue Angel". Ultimately in my situation there were two problems - one was RFI at my location (which was clear after moving the amp) and the other was a bad capacitor. A quick repair to address the 'singing cap' and we were good to go (especially once I moved to a new apartment and the amp had a friendlier environment). Unfortunately, I sold the amp to pay for my first wife's engagement ring... woof, did I get it wrong with that one lol :D :D :D
Never heard an amp do this before, ideas?
I have a primaluna 100 unplugged from any inputs. It has this awful high pitched sound coming from the speakers when it's turned on. It happens on both channels, and through headphones.
I have turned off all electricity in the apartment, turned all breakers off except the one it's on, moved the amp around the apartment, tried a humx, and different power cables. I even replaced the unit with another primaluna and they both do it.
I'm running out of ideas, anyone ever seen this before?