Buzzing in turntables/speakers

I have a Gemini TT-1100 USB turntable connected to a Behringer PP400 Ultra-Compact Phono Preamp and some Klipsch Promedia 2.1 speakers. There is always a constant buzzing sound coming through the speakers while connected to the turntable. It is really only audible when no other sound is playing, but during silences or in between songs, it is noticeable. What could be causing this? Is it because I don't have everything connected to a receiver? Note that the speakers sound clear when connected to my TV or my laptop.

 

Sounds like it could be a ground issue - do you have a ground wire connected between the turntable and the preamp?

 

Yep, the RCA cable that connects the turntable and the preamp has a ground wire part, and I connected them to the grounding peg or whatever you call it on both the preamp and turntable. The turntable was bought used, so maybe I should buy a new cable?

 

I'd try running the ground cable to a different ground on your receiver...perhaps a different screw that connects the cover to the chassis.. if that doesn't work, try a new wire from the turntable chassis to the receiver's .