What B&O did should be the least prone to ground loops. Some day I will take it apart and sort it out but so far I have no ground loop problems with it. I just now verified with an ohmmeter that my cartridge returns and arm ground are connected together in the turntable. Why I didn't do that with the SME I don't know. The arm ground should go to the turntable chassis ground and then that node should connect to the ground terminal on your pre-amp. My recommendation is if possible keep the arm ground and the cartridge returns isolated from each other. I did not follow the advice which I will give you. I used RG188 which is Teflon insulated 50 Ohm RF cable. As I remember I just soldered cables to the SME terminal board.