getting hum sound from sub

[Shake The Rug]

As I said in the previous post, I'm getting a hum from the subwoofer (I have a Polk 5.1 speaker system) and it's just loud enough to drive me bananas. No, the power cord does not have 3 prongs.. only 2 so I don't think it's a "ground" issue. I tried taking the power cord out of the surge protector that everything else is plugged into and plugged it into the wall directly (just as a test) and the hum still could be heard. There's only one cable plugged into the back of the sub - a high quality sub cable that goes into the back of the receiver. However, even if I pull this cable out, the hum can still be heard so I know it's a power thing. I don't think I necessarily have a bad sub as I've heard this is a very common problem. My sub does have 3 settings (on, off, and standby) but I'm trying to figure out how to get the sub to power off and on with my receiver (see other post) :-) Of course there was no manual that came with my Polk speakers and a lot of what is written in my Yamaha receiver manual goes over my head. Right now I'm just manually hitting the switch on the back of my sub to turn it on everytime I wanna use the stereo... but I know that's gonna get old quick. Can anyone help?

[likeitloud]

Run the cable through a RF filter, Ebtech "Hum Buster" or Clean Box(forget the company).
That plate amp may also be on its last legs. Later.

[hydroman]

Mine as well. It is a Denon. I (wrongly) use the switched outlet on the H/K reciever. It is tolerable.