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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

Showing 4 responses by erik_squires

erik_squires
15,627 posts
 
For the record, residential electrical feed is single split phase.


Technically true, but I never suggested the OP should do this him/her self.

Best,
E

erik_squires
15,627 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.
erik_squires
15,627 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. 
erik_squires
15,627 posts
 
This happens due to DC being inserted. It happens when the device takes high current from one cycle, but not the other. A number of things may do this, especially dimmers and high efficiency bulbs and LED power supplies. 


You could possibly fix this with isolating the bathroom circuit back to the main panel, but there's' no guarantee. 


The most certain fix is using balanced power conditioners, but they are expensive and not worth it for short periods of time. 
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