Dealing with transformer hum

Photon46 is right on the mark. I have a Belles 150a hotrod which also had an intermitant transformer hum which I eventually tracked down to a humidifier on the other side of my apartment. Took me forever to isolate this. Before I figured this out I did try an AC power conditioner which solved the problem although I did feel it constricted the amp somewhat. I should add, hum issue solved, that I think this is a great amplifier. Good luck!

As mentioned, many appliances set off the humming. Even though I have dedicated lines from a separate sub-panel, I still hear the hum whenever the microwave is used. Other motors and appliances do the same. Worst case, you may need to go to a line conditioner of some sort -- preferably one that attacks both small amounts of dc voltage that could be in the line (you could check that) and the spurious high frequency noise that is part of our AC system.

I've got to agree. Mine hums if the dryer is running (I told my wife I'd beat her if she does THAT again!), microwave, etc.... I don't like to use a power conditioner with this amp. It normally sees duty as a sub amp, and the hum is never noticable there.

But, now I've got it hooked up in my main stereo system so I can track down a problem with my Audio Note amp. Mated to the Supratek Syrah with 93db AN speakers, any noise on the amp end comes through.

Admittedly, it's a pain in the A@#, but I do like the amp. So, I just have to be careful to schedule my listening time when the old lady's not home to turn shit on and annoy me! FWIW

My rig uses short paths throughout run from pole to meter base/through dual dedicated to units(less 40')second breaker after a/c,yet I heard torriodial humming late evening when the noise floor drops.
Tracked it down by throwing breakers off line one by one. Narrowed down the offending circuits,outdoor lighting transformer,toothbrush charger,cheap radio,refrig. So now I just throw those breakers off,when turning on the audio breakers.Ahhh ,the details emerge from a black hole now!

Interesting ideas. I don't know how thrilled my parents will be at me cutting off their electricity for my late night listening sessions. Hopefully they have some candles nearby or something. I kid.

Thanks for all the input. Like most Belles users, I really love my amp, save for this one annoyance that I can hopefully solve.