I took a second wire and ran it from the ground post on my turntable to the earth post on the plug of my surge protector - basically I just wrapped the 3rd post on the plug. With the main wire in place, put your finger on the turntable ground post. If this diminished the noise at all then additional grounding should help. It touching the post doesn't help any then the second ground wire might not do much either. Over time I've accepted that the problem I had is only really a problem at higher than normal volumes. Part of the solution for me was to decide to stop worrying about it. Oh, - and save up for a higher end turntable.