Rotel 5 channel amp causes hum through speakers

Bypass the PLC and see what happens.

I had a Rotel. I used a cheater plug. Thats a plug that turns a 3 prong plug into two. Available at Radio Shack and most hardware stores. Also experiment if you have Cable TV hooked up within your system. If so disconnect it to see if it goes away. If so thier are alternate remedies.

Make sure it isn't happening with you TV on only. I find the same thing with my Parasound amp. TV on, hum, TV off, no hum. Some after market PC's such as PS Audio's nicer ones have a removable ground pin. Also, Ernie M (Subaruguru) sells a PC that has a disconnect on the ground. You can then use a good quality PC rather than put a cheater in the mix. I suggest the cheater as a cheap way to check if this is a potential fix however.

Had a similar problem which turned out to be the cable TV feed coming in my place. Once I placed a ground device on it, hum was gone.