I have two receivers in two separate rooms connected to each other via two 20 ft optical cables and two 20 ft analog rca interconnects. The in/out on either receiver goes to the out/in on the other, that way I can mirror sound in both rooms from all my digital and analog devices. Anyway, here's the (analog) signal path I'm trying to get to work: Cassette Deck -> Receiver 1 -> Receiver 2 -> Computer. (I'm working on trying to get computer to record my cassettes.)

Now for digital devices, the setup works great. I can play a DVD in my living room and have a very clean signal in my study (I attribute this to the optical cable). For analog devices, it's not quite so good. In Cassette Deck -> Computer signal path above, I have a constant line buzz noise on the speakers connected to Receiver 2. I tried disconnecting the output rca cable from receiver 1 and the buzz disappeared, so apparently it only exists when a signal is getting sent that rca cable (i.e., the cable is not picking up the buzz sound on its own from outside influences). Even when I'm not playing a tape, I can still hear the buzz from the Receiver 2 speakers -- simply having the two receivers connected over such a long run causes it.

The rca cable is a 20 ft radio shack red/white interconnect, and I think this may be the problem. My theory is that the signals in the rca cable are suffering inductive interference -- it's in a fairly hostile environment, since it runs right alongside three speaker cables and a coax line for about 15 feet of its 20 foot length.

Any suggestions on how to fix this? My next step to validate my theory would be to disconnect receiver #2 and put it within 3 ft of receiver #1 and see if it gets that same buzz (in which case I blame the receiver, not the cable), but this is a pain because I hafta disconnect all the connections to move it to the other room for a quick test. Do you think I should do this, or is it more likely to be the cable's fault?

If it is the cable's fault, any suggestions on a set of decent-quality shielded 20 ft RCA interconnect cables that I might purchase? Thanks in advance for any help!