What are the audio differences you hear with turntable Mats.

I might be wrong, but my impression is you need to use a record clamp with the Oracle mat due to the concaved nature of it.  
 

Does anyone know if you need to use a record clamp with the BA The Mat?

Thank you,

Don

@no_regrets , as stated in my previous post, no, you do not need a clamp on Oracle mat! I’ve been using one for 12 years, so I should know. The concavity is not that deep. Any weight will suffice, even the featherwight Gravity One that I prefer. Nor is a clamp needed on the BA mat, which I have had for 3 years. Cannot say it any plainer than this. I’m getting the sense that people just aren’t reading my posts!

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.

@wrm57, Please accept my most sincere apologies.  I have suffered 5 major strokes and there are times when I don't comprehend/understand or process thoughts very well.  It can be very frustrating to me as well as to others... so for that I am very sorry.

I have read your posts and I greatly appreciate you taking the time to share your thoughts and experiences with me and others.

When I read your previous post, you had written...."It works perfectly well with weights and clamps other than the one made by Oracle. Personally, I like the Origin Live Gravity One (out of many I’ve tried), which weighs almost nothing but sounds terrific on the Lenco."   To my mind, that tells me that you have successfully used the Oracle mat perfectly well with several "weights and clamps" but you prefer the Origin Live Gravity One which weighs almost nothing ( but yet, it is still a record clamp/weight, is it not?)  I did not see anywhere in your post where you specifically said that the Oracle Mat does not need to be used with a record clamp/weight.

So, with my challenged brain... I guess I didn't understand that what you may have meant to say is that because the Gravity One weighs almost nothing, that it would be the same as not using a clamp/weight at all.  Is this what you were implying?

It is helpful to know that a record weight/clamp is also not needed to be used on the BA mat.  Thank you for that.

Please forgive my "slowness" in understanding and don't give up on sharing your thoughts and experiences with us, as I and others do indeed appreciate your contributions.

Best wishes to all,

Don

no_regrets, I do use a both a weight (about 250g) and a clamp (SOTA) with Boston Audio mats (two different turntables).  However, with a bare platter surface that is concave or dished as mentioned above, I don't know how that would work out as the graphite is not very flexible, if at all flexible, so it would not readily conform to a concave platter surface. And there would be a remote danger of the BA mat shattering if too much pressure was applied at the spindle over a concave surface.