For point of clarification it wasn't an AVR that was causing any ground loop issue, but, the adjacent cable box which is not uncommon. Initially, I was using the regular RCA(unbalanced)connections with my current Pre-Pro because the amp I previously had connected had no balanced connection option and at that point I actually had no problem with the ground loop hum. It started when I upgraded to a considerably more powerful pair of multi channel amps that had both connection options and although a filter I purchased got rid of most of the hum, late at night when I was watching a movie at low volume , some hum was audible, so it still bothered me. It seems sometimes when you introduce larger power supplies into the picture cable boxes don't want to "play nice" with them, hence, the hum. My audio friend suggested trying the balanced connections so I bought a set on-line, connected them which ultimately, got rid of the balance of the hum. Of course, this was my experience so others may not have the same problem, it was just a case of a Pre-Pro would give one that connection option that an AVR wouldn't.
I have seen on-line alot of A/V "coinosseurs" with "separates" recommending the "balanced" connection route anyway because they are built in such a way to deal more efficiently with any potential noise issues and the connections are more secure.
Last edited by casey01; 02/21/21 12:24 AM.
