On April 9, 2024 at 16:21, Mac Burks (39) said...
In a home theater where we had a 35' RG59 and a 16/4 ran between a surround receiver and a powered sub...
The RG59 was causing a crazy hum in the sub. The 16/2 was ran JIC we went with a passive sub. Out of desperation i soldered an RCA male at each end of the 16/2 and it worked just fine.
Whatever caused the hum with the RG59 wasn't bothering the 16/2. I don't remember what the RG59 was but we used it often for line level audio back then. Never had any issues with it until that subwoofer.
The RG59 was most likely causing a ground loop. Differential in electrical phases would be my guess. The circuit used for your rack was on a different phase than the circuit being used for the sub.
