Ground loop filter noise isolator, eliminating the hiss, buzz and interference caused by ground loops which happens when the audio source and the speaker use the same power source in some car speakers ...

I recently set up a cheap little A/V system with parts my friend gave me. It sounds pretty good, but when I attach my VCR (still have one...) to the input on my Sony TA-AX380 control amp, I get a ...

So in my car I think i have a ground loop problem, but im not positive. Its sort of a cyclical noise, so its quiet, then buzzes, quiet, then buzzes, etc. Its not terribly bad, I really dont notice it ...

So you just unboxed your new entertainment gear, hooked everything up, and you hear buzz, whine, hiss, chatter, or any number of other annoying noises that have been known to plague audio equipment.