My Marantz TT-15 and Parasound JC3 don't get along

I'm having compatibility issues between my Marantz TT-15s1 turntable and a Parasound JC3 preamp. I'm hoping someone on this forum might have some suggestions as to why.

Here's the story (in brief):

I had a Marantz TT-15s1 turntable and a Clearaudio Basic + preamp. They got along well and everything sounded good. Then my house got burglarized, and the thieves took the turntable and preamp. Thankfully, they left my NAD 375BEE integrated amp and speakers.

I liked the Marantz turntable, so I repurchased it. While I was happy with the Clearaudio Basic + preamp, I thought I'd upgrade to the Parasound JC3. I'd read all the glowing reviews, so I thought I'd try it out.

When I hooked up the new Marantz TT-15s1 turntable to the new Parasound JC3, I got a loud buzzing hum. I swapped out my interconnects, I tried grounding to my power conditioner, I made sure the settings on the JC3 were correct and nothing changed -- loud buzzing hum every time.

Since both units were new and untested, I wasn't sure where the problem was. I bought the turntable locally, so I brought the Marantz and Parasound to the shop and hooked everything up through a Dennon receiver the shop had on display. Same problem. We switched the interconnects again and the loud hum was still there.

When we ran the Marantz though the Dennon's photo preamp, the hum went away. We also tried the Marantz with a Moon 110LP phono preamp through the Dennon's aux input and, again, it worked fine.

So I thought there must be a problem with the Parasound JC3, right? I sent it back to Parasound. They ran it through its paces with various turntables -- with MC and MM cartridges -- and said they can't find anything wrong with it. (My Marantz TT-15s1 has a Clearaudio Virtuoso MM cartridge.)

My turntable works. The preamp works. They just don't work together. And I can't figure out why.

Any ideas?
I had a similar problem years ago with a McIntosh C39, Rega P25 with Benz Glider and a number of phono stages, Creek, Phenonomen, and another I can't remember. I tried a Naim Stageline and dead quiet. I can't tell you what the incompatability was but they all had that hum. I did try different RFI Chokes and EMI isolation and could gain some reduction in hum but not elimination. You could either buy a different phono stage or spend a lot of money trying to eliminate the RFI/EMI with tweeks. IF and I do say IF that is the problem. It may be something else and maybe something simple. Will the dealer let you trade the Parasound back in?
I hope for your sake that you've taken steps to make your place more secure. Burglar's will commonly return to locations where they've stolen hi end electronics gear on the likelihood that a homeowner will make a new purchase after an insurance settlement. Any experienced law enforcement officer will make worthy recommendations. Post alarm signs at the curb for starters, and consider an alarm system. Good luck!
Grounding issues are ticklish things to take care of .... If there is a 3 prong plug on your preamp, use a cheater to eliminate the 3rd ground. If that doesn't work, use a thin wire you have around the house to ground the turntable to the preamp. If that doesn't work, get a long extension cord and plug the turntable into a socket that's not on the same circuit as the preamp....and so it goes.
I've have the same problem with the JC-3,a loud hum and I tried all different grouding connections switching outlets but no success and returned the unit to AUDIO ADVISOR which refunded my money (great guys to deal with). My equipment as follows is a Parasound C2 processor a Parasound A51 amp and my turntable is a Clearaudio Performance with a .4mv Benz Glider all going through a PS Audio P5 power plant.
I would add a Mossberg 18 gauge shotgun to your system. It won't cure the hum, but will discourage further burglaries! Seriously, it seems like there might be either design or quality control issues with the JC-3.
Not at all, Bondmanp. My customers love the JC 3, no noise issues. There's a lot we don't know without seeing what's there.