Amplifier HUM


About 6 months ago I completed building a pair of AudioNote 300B parallel mono block amps. I love the sound, but hate the hum I'm hearing from 15+ feet away. I have gone over and over the circuit, changed the location of wires, re-soldered many points, and done the usual things such as lift the ground wire, and some unusual things such as purchase a PS Audio Humbuster. NOTHING eliminates the hum, or even reduces it. The hum emanates from the mains transformer, and combines with the speaker to produce a most annoying situation. I am using PHY speakers mounted in an open baffle. I don't seem to be as annoyed when I use a "box" speaker. The PHY has a pizzo tweeter, and I've read that that can upset some transformers, but I've disconnected the tweeter, and the hum persists. Any thoughts will be appreciated. Again, I love this speaker/amp combo, but am about to shelve the amps. Thanks.
dawg

Showing 1 response by roscoeiii

I've got hum probs too, that only exist for my 45 tube amp. Not a problem when it is plugged into other folks' systems, so a prob somehow connected with my apt.

Dawg, is the hum present even when the amp is only plugged into the speakers, and no inputs plugged in? That is my case, and the hum satys constant no matter what the attenuator is set to, even turned all the way down...