Three immediate things to check:
1. make sure TT ground is connected to good ground point;
2. make sure preamp ground is good;
3. make sure that interconnects are solidly seated.
If all this checks out OK, you may have a ground problem with the cartridge.
1. make sure TT ground is connected to good ground point;
2. make sure preamp ground is good;
3. make sure that interconnects are solidly seated.
If all this checks out OK, you may have a ground problem with the cartridge.