2. amps-preamps
  3. 1275515892

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 livin_262002

livin_262002
187 posts
 
I had a terrible (transformer) hum problem in my B&K MC101 preamp and my Integrated Amp. Both units use toroidal transformers. It was a mechanical hum and not the speaker (ground loop) hum. It drove me nuts too, till I installed a DC blocker between the wall outlet and the units. One of the A'goner was kind enough to build me one for a very reasonable price. If you have a good understanding of electrical components you can build one for very cheap. I now use PS Audio UPC 200HB and there's no trace of hum, even when I put by ear against the amp.

Hope this helps.
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