Hum in Sub


Curious issue w my Sub. Paradigm Monitor 10. When I use my turn table It gets a random intermittent low level hum Just in the sub. 60 hz I think. It comes and goes every few seconds. It doesn't hum when I use any other source; CD, Computer etc. Oddly enough when I listen back to my TT thru headphones its perfectly clean, so I'm quite sure it's not my Pre-amp or TT. TT is a VPI Scout. Phono Pre is a Pro-Ject Tube Box S. Integrated Amp is Peachtree Audio Nova 300. I also have another set up consisting of a pair of KEF LS50Ws. When I connect the sub and same sources the sub does exactly the same thing. Again no other source causes this random intermittent low level hum in the sub. Wondering if I should ground the TT to the Sub? I've seen a few posts talking about locating the sub further away from the TT. I might try that too. Any input would be appreciated. Aside from this minor annoyance, my system sounds great on all sources.
ronwave
When you say a second setup, is it in a different room? And exactly what do they share? Do you move the turntable or more? 

Check the cables between your cartridge and pre. Gently touch the tonearm cable as well. See if you can cause the problem mechanically. 

Try to ensure you keep your turntable and the cables away from AC noise sources such as power cables, amps and preamps. Especially anything with a transformer in it. 
Probably a ground loop hum. Is your sub plugged into a different circuit than your turntable?