I don't have a cable box.
The inputs to the Marantz are CAT 6 network cable, HDMI from HTPC,
The outputs from the Marantz are HDMI to JVC RS-50 Projector, Front L,C,R XLR to active xover, Rear L,R RCA to powered Sub

Everything is plugged into the Furman AR1220, which has a home run 20A pulled to breaker box.

I have attached a ground strap from the Marantz to the Outlaw, no change.

With no signal (no cables) into the Outlaw there is no hum.

I have tried to isolate this by eliminating components, but to no avail