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
The wiring in your house can be the culprit. Somewhere along the way some lines are shared which shouldn't be. In the meantime, may I suggest having your wife, it she's so inclined, go the Sinead O'conner route? 😄

All the best,
Nonoise
No big deal. The low speed of the dryer fan is similar to a dimmer switch for a lamp. The lower voltage causes the audible hum via the shared circuit. The higher fan speed is at full voltage - no audible hum.

Most good hairdryers are about 1800 watts - which draws about 15 amps. This is a significant number. The 240 volts from the utility company are split into 2 120volt legs (phases) that are shared by the various circuits in your house. If one leg is affected by carrying more load than the other or has disrupted voltage, than an imbalance occurs. This affects the neutral which is shared by each of the legs (phases).

If there was a wiring problem, your house would have burned down a long time ago.

Hi mtrot,
DC is induced in the line, refrigerators, heating elements....hair dryers (especially). Has nothing to do with new or old houses and lines. DC can be picked up even at nearby station and distributed to your house easily. Can only be cured with the addition of DC filtering (i have tried it it works). Apart from buzzing noises more heat is generated also.
Post removed 
How will throwing out the current hair dryer help? They all have variable power settings.

Please no one suggest throwing the wife out....   but possibly would she get's a buzz cut?
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. If you’re worried about your wiring mtrot this will be worth it for peace of mind alone.

Three great big utility cables bring power into the panel. Two are connected to the breakers, one to each row of circuit breakers. Think of these as one being the 120v positive half of a 60 Hz sine wave, the other being the 120v negative half. Connected together they give 240v.

Easy enough if you want to flip a breaker off and pull it, which if you do you will see two great big copper bus bars. All 120v breakers connect to just one of these. All 240v breakers connect to both.

The third big cable is utility ground. Notice the utility ground is connected to a great big bus bar. Notice all the hot black wires come off each 120v breaker. Notice all the white wires connect to the same utility ground bus bar. So each of these seemingly separate 120v circuits runs from its own individual hot breaker through the house and your outlets and completes back at the same utility ground.

Might want to read the above sentence one more time. Because this is kind of hard to sink in. Because people have this false notion that circuits are separate when they are in fact all wired together. Pull the cover and see for yourself.


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. 
Erik is confusing DC offset with AC noise. DC offset is a common cause of hum. Whole different thing.

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.

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.
@millercarbon Your insults don’t bother me. Your stupidity does. You are advising people to do something that is extremely dangerous. Stand down. Safety first and foremost.   Getting a shock from a wall outlet is nothing compared to getting electrocuted from a buss bar.
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 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. 
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.
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 writes:
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.

Right. Easiest would be if there's another same amp breaker directly across just swap the wires relabel the breakers and done.


Does this happen in just the bathroom receptacle? Is that bathroom receptacle a GCFI?

Try running the dryer on another outlet. If the hum persists you may have a grounding issue at the main panel. If there is no hum, check to see if the bathroom outlet has the wires secured/installed correctly. 
OP: 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.

Your assumption is most likely correct. If the family room is on the other end of the house, there’s a good probability that it is on a different circuit than the master bathroom. Swapping wiring around at the utility box for the circuit in the bathroom will not remedy the problem for the other circuit in the family room.

As cleeds pointed out, the wiring in a house can be complex. A master electrician needed to guesstimate the potential loads on each leg (phase) from the HVAC, kitchen appliances, HT in the family room, bathrooms (with hairdryers and curling irons), etc.  Building codes also take these concerns into account.  Most temporary electrical noise from appliances cannot be easily detected - but a good stereo is sensitive enough to be annoyed.

The easiest and least expensive solution is simply to not listen to your stereo while your wife is drying her hair.
Although a potentially pricey option, divorce may fix this "issue" as well ;-)
Even though I have a dedicated line to a dedicated listening room, I still have some hum and sound quality degradation when the dishwasher or blow dryer or clothes dryer are on. 
Agree with @steakster -  The easiest and least expensive solution is simply to not listen to your stereo while your wife is drying her hair.
And that's what I do.

Tom
Hi,
DC present in line is common and is not minimized or eliminated if you have a dedicated line for Audio and does not go away if you use different wall sockets. A nearby station may also be affected occasionally and distribute DC to your home line easily. To make things more complicated not only hair dryers but dimmers, refrigerators, led power supplies, micro wave ovens load DC to a line. Few audio equipment use DC filtering, the rest are more sensitive and their transformers will produce noise and heat most of the time. I have found a way to eliminate the problem through a dedicated DC filter (made of 12x 4700mf/25v caps, one for Power amp and one for sources and preamp). Sonically they are not subtracting .
George
Tell her to stop calling her 240v
toy a blow dryer.
Millercarbon, and several others, please don’t spread misinformation about how residential electrical systems are wired and how they work. Get a real licensed electrician who is qualified if you don’t understand this stuff. If you still want to do your own work, at least get educated on the subject, and make sure you have your electrical safety authority inspect and approve all work you do.

Sorry if this sounds harsh, but if you don’t understand the difference between neutral and ground, and the difference between grounding and bonding, and where to ground and where to bond, you are putting yourself and your families in danger if you undertake your own electrical work. For the record, residential electrical feed is single split phase. 
i used to have an audible hum in my system. I thought at first it was a ground loop and chased it for the better part of a year. I replaced every power supply with low noise, all power cables were upgraded, isolation was added, all fuses switched to synergistic, ps audio noise harvesters, I tried hum -x  and on and on. I even took one of my amps in.
Turns out it was the bug zapper in my detached garage. DC on the line i guess. 
On the bright side, all those upgrades and I have an incredibly accurate and quiet system now. 
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

Sounds like you have it down to two choices- get rid of the hair dryer
or the wife. Your choice.

millercarbon:


"Appears no one so far has ever wired a house or paid much attention to how its wired."


Is there anything you haven't done or not an expert at? 


Thanks much for all the replies!  It's really not a big deal for me; I just thought it was interesting and wanted to get some opinions on the issue.  I did wonder why the buzz only occurred when the drier was on its low fan speed.

Yeah, she doesn't dry her hair that often, so I just don't run the systems while she is using the drier, which is a rather expensive one.  No other device in the house causes the amps to produce any buzz or hum whatsoever.