I recently added a Revel B112 sub to my AV system. I have the cable box and dvd player going into a Creek 5350SE integrated amp. The Creek has a preamp out and a power amp in that is usually closed with a jumper. I’m running the preamp out to the sub, and the line level out from the sub to the power amp in on the Creek, which is connected to Revel M106s.
Since putting the sub in the system I’m getting a quiet white noise hiss from the speakers that does not change volume with the volume knob. The hiss is affected somewhat by switching cable order and even just grabbing one with my hand. It also gets better when I unplug the coax cable from the cable box but I can’t watch tv with the cable unplugged, obviously. However, the hiss does not sound like a normal ground loop hum, which I’ve heard before. It sounds exactly like radio static when you lose a station. I actually think I had a ground loop hum AND this separate hiss, and solved the ground loop by switching outlets and cables, but I’m not sure.
I hope the issue is a bad cable or two so I have some better cables on the way. Before they arrive would it be worth it to get a HumX or 2 and see if they improve things? About a year ago I tried using an in-line coax filter but it didn’t play nice with my digital cable, so that option’s a no go.