No one can assail Thuchan's stated preference based on his listening, but I tend to agree with Geoch; using the felt mat will certainly change the sound from that of the bare copper mat. However, if one does not like the bare copper mat, I believe the better cure would be to get rid of it in favor of a mat made of some other material. I am not sure that the impedance mismatch between a vinyl LP and copper is any worse than the impedance mismatch between felt and a vinyl LP. But that's the key, as Geoch says, IMO. Now Halcro mentions a pigskin mat on top of copper. That may be a completely different story vs felt. (Where the heck did you get a pigskin mat, Halcro?) I like the idea that the LP will probably not slip on pigskin, nor should the pigskin move against the surface of the platter. Also, the impedance of pigskin is likely quite different from that of felt, when matched with a metal like copper. I use the SAEC SS300 mat on my SP10. I have no idea what metal(s) its made of; I read once that it is an "alloy" of something. I tend to like it but I am open-minded about other materials that in principle may have merit, like graphite (or pigskin?).
I once owned a SOTA with a felt mat. Every turntable I have owned since then has sounded better to me in terms of ability to separate notes and musical lines and in bass definition particularly, so I am biased against felt, even though I think the main problem with the SOTA was a stretch-y belt.
I once owned a SOTA with a felt mat. Every turntable I have owned since then has sounded better to me in terms of ability to separate notes and musical lines and in bass definition particularly, so I am biased against felt, even though I think the main problem with the SOTA was a stretch-y belt.