Hi All, can you please assist, I have a NAD T 754 that I bought second hand last year, I've never connected a sub on it, only used it tow front speakers and a center speaker. I was going to buy a sub from a friend PolkAudio PSW12, at works fine at his house, but when I connect it on my amp I only get a humming sound. I've turned on the sub on the on screen menu but still there's no sound just the humming sound. Is it possible the the sub outputs are damaged?
