Axiom Home Page Forums General Discussion Home Theater Am I going insane?

I am having a problem that is driving me crazy. It began when I hooked up a 15" driver to my left main channel to run some test tones (building DIY subwoofer). I realized I had a pronounced hum. I put my front speaker (10 plus year old B&W 2004) back on - realized there was a hum there also.

So I researched ground loop hums - possible culprits include cable TV, wrong polarity of plug, etc. After confirming the polarity of my outlets with my polarity tester, I proceeded to disconnect cable, etc.

In the end, I was left with my receiver (old Sony STR-D1090) and only my speakers. I removed all other connections to my receiver - EVERYTHING. With the volume at listening levels, there is an audible hum a few to several feet away from all speakers, although not very loud. I hook up the 15' driver - slightly louder hum. Even my rear QS8s have a hum from a few feet away. The receiver is grounded to a grounded outlet, but still there is a hum.

Note, no other funky appliances (like a bank of flourescent lights) are on in the house. The house is only 12 years old and the wiring is solid.

Is it just that my receiver a piece of crap? (yes is the default answer, but is that the problem?)

Or is this normal?

When nothing is being played through the receiver, should any hum be heard from speakers?

Any aid for my sanity will be greatly appreciated.

Pete

Do you still hear the hum if the volume is all the way down?

Yeah, that would be my question. Does the hum vary with the volume? I've heard a bit of a hum from my M50s with the volume on the H/K 525 turned almost all the way up (and nothing playing).

It's the fridge

Yes, I hear it with the volume all the way down, but it does get louder with increasing volume.

Pete_D, if I read your posts correctly, the cable tv is not the problem? Try using one outlet and see if the humming stops. If not, borrow another receiver to see if yours is having an issue.

You can try one of these. It has worked for me a few times.

To be more clear, when I turn the volume all the way down, I can still hear a hum. Granted, my ear needs to be within a few feet of the speaker to hear this.

I assume it should be completely quiet in this scenario. Right?

Right now, my polarized plug on the received is plugged into a properly polarized and grounded outlet. I also have a grounding wire running from the grounding terminal on the back of the receiver to the outlet. I have hooked this wire up to the screw on the outlet as well as inserted it into the hole for the grounding prong on the outlet itself.

It seems to me (I am no expert) that this plug may not help in my situation. Have you used it with success in this scenario?

Pete,

What you are describing is exactly how a ground loop occurs to create the hum and the "cheater plug" that has been suggested is the usual, inexpensive and effective fix. Give it a try.