Try the NAD w a line level source. that should help you isolate it. Also check cart leads.
Almighty TT hum --- help
I have seached the archives on the topic of turntable hum and found some info, but nothing that helps my situation, so here goes...I just ressurected an old (23 years) Technics turntable with an Audio Technica cartridge (...I know --- decidedly LOW FI, but I have young kids that suck up virtually all of my time and money). I am aching to get back into vinyl and I just wanted to see what the old table sounded like on the NAD 3020 I bought a couple of years ago. Holy hum, Batman!! Sounds like bad grounding, but I checked and cleaned all connections and that didn't help. The hum is only slightly louder when the ground wire is disconnected altogether. I would like to determine if my old TT is to blame or the old NAD. Any suggestions on my next step would be greatly appreciated.