Hi, New to this forum and have a question I hope someone can answer. Just installed my new Yamaha RX-V1400 and I want to hook up my sub. On my old yamaha, I did not have a sub out so, the b speaker outs were driving the sub. When I ran the wire, I ran 2 pair oxygen free cable under the floor to the sub. For my new reciever, I thought I'd try soldering some RCA plugs to a pair of the wires. The sub works but, I am now getting some 60hz hum. Is there anyway I can use the wire I have in the floor to go from my sub out to my sub? Or, am I going to have to run a sub wire? Is sub wire sheilded? Like coax?