Here is a late breaking tweak, this one really rocks on TT.
After reading about the spot mat on a couple of sites, I made up a quick version of my own.
It consists of a thin sheet of non slip rubber matting (the thinest I have) and nine spots the size of a 20cent coin made from stick on cork, covered with a thin layer of bluetac with thicker non slip rubber mat circles stuck to the blutac.
It is nicely level and easily the best sounding mat I have used, the noise floor seems is gone to virtually inaudible. Nicer bass and improved resolution and the sound was great before the mat so I'm chuffed big time with this one.
I have another idea but it is a little radical, I reckon the remaining residual noise/vibration getting to the LPs would have to come via the spindle (mind you I can't really hear any at all now, but there must be something there according to common sense).
What if a made a little tube that neatly fitted over the spindle, then drilled a larger hole in the LP, then I put the LP on the deck over the dummy spindle. The disc won.t slip at all with the non slip matting on the circles.
Once all is centred I could pull the dummy spindle and I should be left with a disc that is virtually decoupled from the deck completely. I reckon it would take very little effort and If I needed to play the disc on a regular TT I could leave the dummy in place.
The only problem I see is drilling the LP without getting rubbish in the groovese etc.
I have twin copies of several discs so I will try it on one I don't like much.