I'm a newbie here, and this is a long shot hoping that more experienced hands might have some insight. A couple of years ago I built a PC to integrate with my not particularly impressive HT setup. It has hardly been used. But I've got a burning desire to dub some old LPs to CD, and this is my only realistic option. So I fired it up, but have been thwarted by an insidous hum problem. I've spent hours trying to diagnose it, and my conclusion is that I'm SOL. Everything is hooked up thru a fairly modern Denon AVR-4800 receiver. The PC is hooked up to VCR2. When I play a CD on the PC the signal is weak and there is what I think is 60hz hum. It is not the sound card, I just replaced a Guillemot Fortissimo with a Turtle Beach Santa Cruz. What totally befuddles me is that the hum is present only when: 1. The CATV jack is plugged in to the cable box or directly into my VCR (VCR1). 2. VCR Out from the receiver is plugged into the input jack on the sound card. 3. The AC plug is put into the PC, whether is is turned off or on. i.e. the hum occurs only when the CATV and the PC are hooked into the system at the same time. If either one is disconnected the hum disappears (although the actual sound coming from the PC is still weak when the cable is unplugged, but it is clean) Two things baffle me. (a) why does the presence of a CATV cable connected to a different input on the receiver cause a hum when a different input is hooked to the PC sound card, and (b) continues to do so even when the PC is turned off, but plugged in? Any keen insights or possible solutions will be appreciated. O/w it appears that this PC will have to be parted out.