Raul, I am surprised that in your post above, you seem to be saying that the platter mat should be "seen but not heard". That's a good goal, but in fact we know that the platter mat is always heard, even if it is heard to be neutral, which is the way I would put it. Can you say more about the SOTA mat? I used to own a Star Sapphire Series III with vacuum, and as I recall, it had a felt-like material that was glued directly to the main body of the platter; it did not have a removable mat. And of course one could not put a mat on top, because it would interdict the vacuum.
Ferrari, Thank you for pointing out that the MS mats are gunmetal copper, not pure copper. I did not appreciate that fact, because I have never seen, much less owned, an M-S platter mat. I did read that the Tenuto mat is also gunmetal copper, not pure copper. However, my recent experience with a true pure copper mat that I had custom-made for my Kenwood L07D is consistent with your observation that pure copper seems to sound superb, and I do not really know why copper seems superior to all other metal mats I have tried, albeit on turntables other than the L07D. Except whereas Raul concedes that a metal mat may function to block EMI, which I think has a lot to do with its superiority on my L07D.
In this case, the pure copper mat replaced the OEM stainless steel "platter sheet" (Kenwood's term for it) supplied with the L07D. Copper is superior to stainless as an EMI shield, which may account in part for my experience with the L07D. Both mats weigh about 5 lbs; I did not wish to greatly exceed the mass of the stainless steel platter sheet in creating the copper replacement, because the L07D platter is partly supported by magnetic repulsion, and also because I am categorically opposed to using after-market mats that are very much heavier than the OEM mat on DD turntables that rely upon a servo mechanism. It may be OK to do it, up to a point (the capacity to tolerate a very heavy mat without disturbing speed stability) , but that point is likely to be different for different turntables. One would have to test the speed stability on a case by case basis using sensitive equipment, in order to feel certain that no new problem is created by a very heavy mat. And this is in addition to putting stress on the bearing and thrust plate. Just my 2 cents on that subject.
Ferrari, Thank you for pointing out that the MS mats are gunmetal copper, not pure copper. I did not appreciate that fact, because I have never seen, much less owned, an M-S platter mat. I did read that the Tenuto mat is also gunmetal copper, not pure copper. However, my recent experience with a true pure copper mat that I had custom-made for my Kenwood L07D is consistent with your observation that pure copper seems to sound superb, and I do not really know why copper seems superior to all other metal mats I have tried, albeit on turntables other than the L07D. Except whereas Raul concedes that a metal mat may function to block EMI, which I think has a lot to do with its superiority on my L07D.
In this case, the pure copper mat replaced the OEM stainless steel "platter sheet" (Kenwood's term for it) supplied with the L07D. Copper is superior to stainless as an EMI shield, which may account in part for my experience with the L07D. Both mats weigh about 5 lbs; I did not wish to greatly exceed the mass of the stainless steel platter sheet in creating the copper replacement, because the L07D platter is partly supported by magnetic repulsion, and also because I am categorically opposed to using after-market mats that are very much heavier than the OEM mat on DD turntables that rely upon a servo mechanism. It may be OK to do it, up to a point (the capacity to tolerate a very heavy mat without disturbing speed stability) , but that point is likely to be different for different turntables. One would have to test the speed stability on a case by case basis using sensitive equipment, in order to feel certain that no new problem is created by a very heavy mat. And this is in addition to putting stress on the bearing and thrust plate. Just my 2 cents on that subject.
