My semi-expensive (for me) record playing setup is not working properly and it is making me pissy.

So I've got a hand-me-down Pioneer PL-518 with a Grado Green cartridge hooked up to a Bellari VP129 preamp, listening with SR-80s.

Before I moved, I hadn't bought the Green yet and was listening with the OEM cartridge, and it sounded pretty good. I picked up the Green on the way into town, and in the "hay audiostore guyz lemme make sure I'm getting the right thing" process, the old one got fuxored. I installed the new one, but now I'm getting an annoying low hum, most records sound like they're clipping, and even brand new records sound moderately scratchy.

I've got the ground cable attached correctly, did all the tracking/anti-skate stuff, but still no dice.

Any ideas?