Hum in my system; its the turntable R and L interconnects. Huh?

buellrider97 and ditusa, Thanks for your suggestions. I read the article and several others by PS.

1. The hum is created by the TT R and L interconnects even if the TT is not plugged it. If fact plugging it in or out makes no change.

2. I tried using a 2 prong; no change

3. I plugged everything into a HT Monster Power HTS2000 power strip I had on hand; no change. I tried eliminating the ground prong on the power strip, no change. The only thing that works is disconnecting the R & L signal lines from the TT. 

I can only guess that it is a fault inside the TT wiring.

You might also want to try making sure the cartridge clips are tight on the phono cartridge.  Use a needle nose GENTLY and close them down if they are loose.

@jereeb  -  What cables are you running from the turntable to the phono-pre?  Is it possible that they are picking up the 60Hz hum from one of the power cords, the AC wiring in the wall, close by power suppy, etc.  I had a problem once where I was picking up EM interference from a nearby radio station on the cables from my VPI table and the phono-pre.  I could actually hear the radio program/music.  I switched to a set of shielded cables and it went away.

I've also heard, somewhere a long time ago and I don't remember where, that some Grado cartridges are  susceptible to EMI.  Might be complete bs, but might be possible.

Just a thought.

Good tips! I'll try the additional ground wire, dbl check the cartridge clips are tight (pretty sure they are, they were a tight fit going on). The TT cables picking up EM is a suspect as even when the TT is disconnected from power, the hum is there. I am also going to try a different TT later this week.