I trust this is in the correct forum, I'm looking to hopefully find the root cause of my power supply hum in my amp. I don't want to call out any vendors to avoid any negative feedback as I don't believe it's the amps fault. I have been hearing a very faint hum in my toroidal transformer that's well damped. There's a chance I have some DC in my line, but not sure how to verify.
The amp is on a 20A circuit by itself, however it does this in other outlets. The amp is wired from the main panel, however if I shut the 50A feed to my sub panel, the noise stops, even if I turn it back on again. The amp will also hum in a varying pattern if I turn on my Plasma TV which sits about 12" above the amp....the amp is not connected to the sub panel.
The neutral and ground are separate in the sub panel. If I shut off every breaker in the sub panel, the noise remains, only if I kill the feed will it stop. The transformer will either have a very, very faint hum, or it will be slightly loud, when it's loud I can stop it by turning off the breaker for the sub panel,
Also, when the hum is quieter, if I kill all the breakers in the.. main panel except for the 20A circuit for the amp, the hum is still audible.
Sometimes there is no noise, so just trying what could cause the transformer to hum.
Outlets are good, new wire, power cords are good, what's really odd is when the plasma is on, it hums in waves, comes and goes.\
All thoughts and crititicism appreciated.