Humming from center with sub plugged in.

I have an EP350 subwoofer and a VP150 center connected to my Onkyo TX-RZ820 along with the M60 for a 3.1 system. I can hear some buzzing from the center when the sub is connected, whether its powered on or not. Any suggestions?

Is the sub plugged into the same outlet as the 820?

Originally Posted by rrlev

Is the sub plugged into the same outlet as the 820?

Its plugged into a power conditioner and the sub is on the non-switched outlet. I will try on a different outlet and report back.

First just unplug the sub and see what you get. I'd then try bypassing the conditioner (plug directly into the outlet). If that doesn't help move the sub or get a heavy extension and try same outlet as the reciever ...

Just an update on this. I havent been able to resolve the issue and need a longer power cord in order to get to another plug that is not connected to the same as the stereo.
I just found another cord. The problem is when Axiom updated the sub they changed the amplifier. I was able to get the updated sub amp and it no longer has an RCA type input but replaced with a 1/4. That is loose and causing the humming. I am just going to replace the sub with another brand.

Seems like an expensive solution but I'm not there and don't know what you've tried.

Have you tried to make the repair yourself? Might be super easy and save you some money.

Actually I think I'd lay money down that the replacement sub does the same thing ... i.e. you said it happens when it's off. Sounds very ground loopy to me ...

Originally Posted by TrevorM

Have you tried to make the repair yourself? Might be super easy and save you some money.

I did replace the amp that I received from Axiom to repair the Sub. The problem actually started when I replaced this. I can shake the cable in the back of the sub and hear it cut out.

Originally Posted by rrlev

Actually I think I'd lay money down that the replacement sub does the same thing ... i.e. you said it happens when it's off. Sounds very ground loopy to me ...

This happened in my old house before I moved too. I am going to try a Klipsch from Costco and see if I can replicate it.

Here are some of the reviews from Costco's website on the Klipsch R-12SW Reference Powered Subwoofer:

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Got it from Costco online and loved it very much. After turning off AV, the humming noise was expected to stop after a few minutes and it did. Unfortunately, the humming noise lasted longer and longer each day. In less than a week, the humming noise did not stop. Tried switching it to off and unplug the power core several times. No help. The humming noise came back non-stop in either auto or on position. Had to return it to the store.

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The speaker sounds great but has a loud hum when not in use.

Again, for what it’s worth, my guess is that the problem is most likely up stream from the sub (assuming that the sub,“conditioner” and outlets are wired correctly ... both internally & externally).