2. misc-audio
  3. 149105-154

Blow dryer causes audible buzz from power amps in two audio systems...

but only at one speed.  My wife's hair blow dryer causes the amps in both my bedroom system and family room system to audibly buzz.  It only causes the buzz when the blow dryer is on its low fan speed.  Strange.  The bedroom system is close to the master bathroom, where she uses the blow dryer.  But the family room is on the other end of the house and I assume on a completely different circuit.  Now, it does not cause any problem with the audio that the amps are producing.  It is just an audible buzz you can hear coming from the amp. Does this mean there is something wrong with the wiring in my house?  The house was built in 1987.
mtrot
Post removed 
Ag insider logo xs@2x
cleeds
5,960 posts
 
millercarbon
Appears no one so far has ever wired a house or paid much attention to how its wired. Takes about 90 seconds and a flat blade screw driver to see for yourself what is going on.
Nonsense. It takes a lot more than 90 seconds to ascertain whether a house is properly wired. It will require more than a flat blade screw driver to conduct that assessment.

Three great big utility cables bring power into the panel. Two are connected to the breakers, one to each row of circuit breakers.
That is mistaken. In a typical breaker box, each row contains both phases of power, which alternate between each breaker position. That's how a 240VAC breaker gets its power - one from each leg.

 
erik_squires
16,144 posts
 
Erik is confusing DC offset with AC noise. DC offset is a common cause of hum. Whole different thing.


No I am not. I quoteth the OP:


  Now, it does not cause any problem with the audio that the amps are producing. It is just an audible buzz you can hear coming from the amp.

DC can be produced in short, subcycle, durations as well. I know because I have seen it on a scope. 
millercarbon's avatar
millercarbon
12,531 posts
 
Hey if its coming from the amp, mechanically not in the signal coming out the speakers, then its definitely DC offset. Causes the transformers to vibrate producing a hum. Missed that bit. My bad.
There's a power strip that solves this. Furutech? Whatever. Not expensive either.
erik_squires
16,144 posts
 
One possible easy solution is to move the bathroom circuit to another phase. May work if it happens to share the same phase as the two amps.
More to discover