# Plugging plasma tv into outlet causes other equipment to hum/buzz



## george_k (Jan 23, 2010)

I noticed my subwoofer was humming today... I seldom turn it on as I live in an apartment building and don't want to annoy the neighbors too much.

I unplugged everything except the subwoofer and proceeded to plug in one component at a time. As soon as I plugged in my Pioneer 5010FD plasma tv, my subwoofer started to hum. I tried a seperate circuit used only by my amplifer and as soon as I plugged in the tv, the amplifier started humming as well.

The hum is there even when the tv is plugged in but powered off with all its inputs disconnected.

I did some searching on ground loops and could find any cases that were similar to mine. I don't subscribe to cable or satellite service. I strictly use this system for bluray/dvd movies and music.

Anybody have any suggestions?


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## dahlke2 (Aug 30, 2010)

Does the power cable for the TV run alongside the amplifier or sub signal cables? Sometimes the signal cables can pick up the 60Hz signal from the power. If the power cable for your TV has only two prongs try flipping the plug around.


> The hum is there even when the tv is plugged in but powered off with all its inputs disconnected.


 Is the output from the TV unplugged as well? If it is the only explanation would be a ground loop. If you did have output plugged in, the output from the TV must be picking up electrical noise from TV electronics.


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## lcaillo (May 2, 2006)

Plug all of your equipment in to the same outlets or at least the same circuit. Do you have any connections to a network or any other equipment?


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## george_k (Jan 23, 2010)

I'll try moving around the tv power cable or swapping it with a more heavy-duty one. The power cable is the same as what you'd use to plug in your computer (i.e. 3-prong). The cable runs down the tv stand's wire management loops and then along the wall to the surge bar.

I do have some components of my setup networked to my home computer (e.g. playstation, xbox, media computer).

I'm fairly certain the tv is the culprit as the moment I unplug it, the noise goes away and as soon as I plug it back in (even if the tv's power switch is off) the noise starts up again.

I'll try messing with the cable and report back.


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## Jason1976 (Aug 13, 2009)

hmm I wonder if a capasitor or another part in the tv maybe going bad and making a voltage leak or something. No way of knowning without a tech looking.


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## mr.chuckles (Jan 23, 2011)

Here's something to try, what TV service do you have? Cable, Sat, FIOS, etc..... Try unscrewing the coax from the set-top-box and see if the hum goes away. I've run into numerous situations where the building ground is poor and the devices (mainly Plasma TV's) are using the coax to get to ground, because the cable ground offers the least resistance. I've got into serious "back and forth" with building supers and power companies about that issue.


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