Hi and thanks for the replies. Since my post I have learned a couple of things. First is about grounding plugs to test a particular component. You insert grounding plugs in place of the interconnects to complete the circuit and this allows you to test an individual component for noise. So with regard to the headshell you are correct, it needs to be in the circuit, if you ground each channel of the headshell, in other words a lead between the plus and minus you can test for noise. In my case I needed a ground from the tt itself to the grounding lug on the preamp.
Again thanks for the replies.
