To Kr4--Searching here probably would be more useful.
Tim, a ground loop is a situation in which electical components in one system get plugged into electrical outlets with grounds (neutrals/commons) unintentionally at different zero voltages. Hence the different chassis are at different 'zero' voltages (all of which SHOULD be zero but aren't). Current then flows thru the common legs of interconnect cables and induces 60- or 120-cycle hum into the signal. It happens quite often in systems with many pieces of equipment (such as mine, damn it!), and it's most-easily patched (but not solved) by floating (detaching) the offending equipment's third-wire ground. I said 'patched' above because while the system's most-obvious hum may be mostly gone, there's still low-level garbage deteriorating to some extant the sound quality.
The real solution is to have one's house or at least room rewired by someone who knows how to bring EVERY outlet in the room to the same 'ground'.
.
Tim, a ground loop is a situation in which electical components in one system get plugged into electrical outlets with grounds (neutrals/commons) unintentionally at different zero voltages. Hence the different chassis are at different 'zero' voltages (all of which SHOULD be zero but aren't). Current then flows thru the common legs of interconnect cables and induces 60- or 120-cycle hum into the signal. It happens quite often in systems with many pieces of equipment (such as mine, damn it!), and it's most-easily patched (but not solved) by floating (detaching) the offending equipment's third-wire ground. I said 'patched' above because while the system's most-obvious hum may be mostly gone, there's still low-level garbage deteriorating to some extant the sound quality.
The real solution is to have one's house or at least room rewired by someone who knows how to bring EVERY outlet in the room to the same 'ground'.
.