Speaker noise

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PPBart

Member
Just in the past month or so...

I missed my own best clue to solving the mystery. On December 1st (IIRC) we had our home security upgraded to a wireless system (in part so we could finally drop the landline). The security system router was positioned inside a closet (out of sight, out of mind) adjacent to my office where the affected speakers ares located. I was reminded of the change when I got an email notice of the monthly bill this morning. I unplugged the power to the security system router and the noise vanished. Now I'm wondering what to do next...

There is no clicking in my headphones, but I really don't want to wear those all the time. The speakers are probably 8-10 yrs old. Would current technology provide better shielding against external interference?
 
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Agent Smith

Agent Smith

Well-Known Member
It could be the speakers, like a capacitor. Could be that you need a driver update for the sound card too. Not sure.
 
Darren

Darren

Moderator
Staff member
My old set of computer speakers would make a clicking sound when my bathroom down the hall would have its light switch flipped. Probably some kind of surge or something that's making that noise. I don't know how to fix it but it's going to be a wiring problem in the house. Maybe try different speakers or a different outlet for them. Or even a surge protector might help.
 
Okedokey

Okedokey

Well-Known Member
That's typically caused by a diode rectification effect in the preamp or amplifier input stage. It's more likely to happen with AM-band radio reception but any AM-type radio signal could theoretically be picked up. Once half of the carrier is chopped off, the residual signal looks approximately like an audio-frequency signal riding on a DC offset. An AM receiver would perform this step intentionally, but any audio circuit with a BJT transistor can approximate it, and under certain conditions the audio portion of the signal can be passed into the amplifier.

What's happening here is very likely an ordinary ground loop, but those can be notoriously difficult to chase out. Browse any DIY audio forum, and even the veterans will be posting for advice periodically.

My advice is to switch the amplifier to a different power circuit to the security system if possible. Failing that, a line-conditioner is another option.

http://www.newegg.com/Product/Produ...cm_re=line_conditioner-_-42-111-281-_-Product
 
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PPBart

Member
Okedokey said:
...My advice is to switch the amplifier to a different power circuit to the security system if possible...
Click to expand...

OK, there are two duplex outlets at opposite ends of my desk and I already knew they were on different circuits. I moved the speakers power brick from one outlet to another and the noise went away. Thanks for the info!
 
Okedokey

Okedokey

Well-Known Member
PPBart said:
OK, there are two duplex outlets at opposite ends of my desk and I already knew they were on different circuits. I moved the speakers power brick from one outlet to another and the noise went away. Thanks for the info!
Click to expand...

You're welcome.
 
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