What are the audio differences you hear with turntable Mats.

For those looking for a great reflex clamp, don’t forget about the two made by BDR (Black Diamond Racing): a solid 1-pc., and a 2-pc.. Made of Carbon Fiber, with 1/4-20 threading. They show up on USAM used every once in a while for about $150.

Frank Smillie of Groovetracer renown (he makes excellent Rega upgrade parts. I visited his shop in San Jose, and was very impressed.) machines a turntable platter for Rega tables in both Acrylic and Delrin versions. Here’s what he has to say about Delrin:

"Delrin is considered the material of choice for record platters by the many of today’s high end turntable manufactures (that may be debatable). There are several reasons for this but the primary consideration is that it shares many of the same properties of the vinyl record. It also carries more mass than the majority of high performance thermoplastics which is important in maintaining speed stability."

"The sonic benefits include well balanced frequency response with no loss in dynamics. Upper frequencies are better defined which in turn allows more inner detail to shine through. The improved presentation of instruments within the soundstage provides better imaging."

Harry Weisfeld made platters for his HW-19 and TNT models in aluminum (with a layer of lead bonded to it’s underside), solid Delrin, an aluminum/Delrin "sandwich", a couple different stainless steel/Delrin sandwiches, a solid Acrylic version, and finally back to aluminum. Delrin became too expensive to manufacture (Frank Smillie again: "The challenge in using Delrin is that it is quite expensive in raw material form and requires extra attention during the manufacturing process."), so VPI made the switch to solid Acrylic. The VPI Acrylic platters are now almost worthless---no one wants them, while the Delrin versions (especially the stainless steel/Delrin TNT-5 version) are very much in demand.

Max Townshend chose Delrin for the LP interface/top layer of the platter on his Rock Elite table, and if I’m not mistaken so did SOTA (right?). I went to a great plastics supply/machining shop in Portland to have armboards made for my VPI Aries and HW-19 tables, and compared raw Acrylic to Delrin. The Delrin was substantially less resonant (when struck Acrylic "rang" quite a bit more than did Delrin), and far greater in mass.

Is anyone making a Delrin platter mat? I’ll bet the Graphite mat is close in nature to Delrin.