The hum is from my new RR2160. Here are the connections that it has (no antennas connected yet):

Power:
- I have only the RR2160 and SVS sub connected to a CyberPower UPS

Audio:
- Digital Coax connection to my hires media player
- Cat 5e network cable
- Single RCA cable from sub output to SVS sub
- Speakers connected

Unfortunately I can't switch to Optical Digital cables/input as they are limited to 24/96 and I have 24/192 music