Record clamp and mats coexistence

What Psychicanimal has stated pretty much coincides with my opinion. I would add that the old Goldman mat on this table with the Michell clam would be a much better combo than what you have.

I have zero experience with the DIY / TNT mat. Do an audition with both if you can swing it.

I have a J A Michell record clamp; I think it's the best performer (dollar for dollar, that is). What you need to watch out is the following:

1) The way it works: it raises the record at the spindle by means of the felt washer and then when the clamp is locked in place it flattens the record (well, not quite, but good enough).

2) The nature of the record mat. Overdamping will destroy bass snap. For example, the guy that sold me my clamp is very knowledgable and has my very same TT. He said not to buy the Audioquest Sorbothane mat on my particular TT because it would smear the bass. I agree.

3) The shape of your mat. It might not be a good match with anything, for what matters. If you can readily adjust VTA, try a regular, cheap rubber mat and listen to it for a week or so. Then switch back.

If you are using a belt drive, you can always try the DIY record mat design in tnt-audio. It addresses my last two considerations and should work very well with your clamp:

http://www.tnt-audio.com/clinica/januse.html