Originally Posted By Stach
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
This type of hum is usually from DC on the AC line. Try turning off any lights, one at a time in the area to see if one of them is the culprit. I'd start with any desktop lighting, or stand-alone lighting fixtures.
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Main HT <> 976 <> 7200 <> Ultra-X12 <> sapphire ST2 mkII RF/LF <> sapphire SC center
sapphire ST2 mkII SBR/SBL <> sapphire SS SR/SL <> Verizon/DVR <> Vizio M70Q7 <> Oppo UDP-203 <> Amazon 4k Fire TV