The first six months of production, the Spacedeck came without a mat. One day, Tom showed up with a mat, saying "hey kid, for anyone who wants a tone control". From then on a mat was supplied as standard but to my ears, the TT sounds far more dynamic used as intended, without a matI never know that.
I presumed the fact that my Ace Spacedeck came with a mat the turntable was designed to be used with it.
I now have the Dais which I use without a mat, as designed.