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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
erik_squires
16,430 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. 
millercarbon's avatar
millercarbon
12,531 posts
 
Erik is confusing DC offset with AC noise. DC offset is a common cause of hum. Whole different thing.
steakster
1,948 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.

It’s a very good idea to understand how a house is wired. It’s an extremely bad idea to mess around the utility box with a flat blade screwdriver. Instant death can occur if you don’t know what you’re doing.

millercarbon's avatar
millercarbon
12,531 posts
 
Well what do you use steakster? Fingernails?

Still I must admit, if you want to avoid ever learning anything irrational fear is a pretty good tactic.
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