SP-10 Mat

Thoughtful exchange above from many posters and valid points, including some helpful direct experiences shared. In my personal experience, the Technics Sp10Mk2 will indeed benefit from the use of an appropriate mat, the exact type and subsequent composition will depend upon the listeners tastes. I for one, enjoy both Copper based mats (i.e.. Micro Seiki CU-180) or a composite (rubber, or cork/rubber/leather) mat used in conjunction with an aluminum based mat, such as the Oyaide MJ-12. In fact, during testing, I found Copper based material to be so desirable, the result early this year was our manufacturing a brand new Sp10Mk2 composite platter consisting of stress relieved Aluminum + Copper. For those who may prefer certain playback characteristics of different materials, I am working on a design revision which will allow interchangeable upper platter combinations.

The material Delrin, solely used as a platter mat material, as suggested above by Mosin, we actually designed and manufactured for a brief period of time but production ceased immediately when the mats began to develop warping anomalies. Their musical characteristics I found to be pleasant, albeit slightly polite. A different type of Delrin composite based platter mat we are developing however, but the release date is unknown. Another issue faced when using pure Delrin is the potential for excessive residual static build up. I've yet to listen to (evaluate) the Boston Audio Mat1 or Mat2, however, the use of Carbon/Graphite seems logical and a good choice for material selection, given its rigidity and density. TTW Carbon hybrid record mats I have heard positive things about, although personally have not had the opportunity to evaluate at length, so I cannot comment.

Lewm, I wholly agree with your assessment of overtly heavy record clamps. In my experience, I have found that time again, they result in more degradation than good. This applies to all drives types mostly, with few if any known exceptions.

A quick word, comment rather, with regards to the Sp10Mk3. Having spent years designing plinths, playing, owning and testing this Technics model, I agree in that they are indeed a reference level analog playback machine and remain worthy of serious consideration. However, the secondary market prices for stock units, in my opinion, have now inflated to an extent which has made them less attractive an option than at one time in the not so distant past. It is for this very reason, that I continue to exploit the undeveloped playback potential of the Sp10Mk2 platform.

With respect to the forum thread poster, my apologies for straying off track of the original record mat subject.

Chris, Have you considered that part of the possible benefit you perceive from copper or copper-containing mats is related to shielding of the cartridge from EMI radiated by the motor? I doubt this is much of an issue for the Mk3, with its massive copper-containing platter (and maybe that's why it contains copper), but it certainly could theoretically help the Mk2. For the Kenwood L07D, the cognoscenti know to add such a shield, even though the platter is already stainless steel, a pretty good shield. I personally heard an improvement, removal of a kind of faint dull coloration, when I added an LP-size shield between the platter and the L07D "platter sheet" (which is 5 lbs of stainless steel). I made it out of TI Shield.

Lew, keen observation. Yes, I believe part of the enhancements gained when using Copper in conjunction with the stock platter I believe is its ability to provide an extra layer of shielding between the powerful motor magnets and stray EMI radiating within the Mk2. Fortunately, the stock factory damped aluminum alloy Mk2 platter exhibits very low levels of magnetism, which aids a hand as well.

I've been following this thread with interest because my latest project, an sp10mkII (early model) is in the works.
Here's a recent photo of the TT up inits plinth and doing its job.
http://www.theanalogdept.com/images/spp6_pics/User510/sp10mkII/Test%20Mule/TMbuild_31.jpg
and a link to the page where I document the entire process:
http://www.theanalogdept.com/user510_sp10_mkii.htm

At present I have the original mat on the unit. I was able to try out a BA mat 1 last Sunday. This was allowed when another sp10mkII owner brought over his BA mat1 for me to try out. I dealt with the obvious problem of the mat thickness being undersize for this TT. I placed a thin mat underneath the BA mat 1 and this resulted in a total mat thickness that was within a few thousandths of the oem mat thickness. this allowed me to hear the difference between my standard mat and the BA1.

Fwiw, I'm using a Graham 2.2 tonearm. And that allows a very convenient method for making adjustments to VTA/SRA on the fly. With that out of the way I can say that the BA mat definitely provided an overall improvement in comparison to the oem mat. The first thing I noticed was greater clarity in the upper frequencies. It might take me more time to fully evaluate the difference. But what I heard was enough to convince me that a solid graphite mat could be the ticket for this motor unit (and likely most others).

It is possible that the thin mat on the bottom may have improved "traction" between platter and mats.

The one negative I noticed about the BA-1 mat was that it was warped. When placed on a flat surface the BA-1 mat showed as much as 1/16th " of warp. And this was apparent as the mat was spinning on the platter. At one point I removed the underneath mat to allow the BA-1 mat to lie directly against the SP10 platter. Warp still the same and VTA was corrected via the Graham VTA adjustment facility. Roughly the same SQ. At least as near as I could tell during this brief listening review.

So my question now is; does anyone else have experience with a BA-1 carbon mat being warped? 2nd quetion would be; is it possible to straighten one of these mats without breaking it? I say this because I noticed that the mat is coated with some sort of polymer that (seems to) give(s) it a certain amount of flexibility.

Another thought to put out there:
Has anyone tried one of these players with a vacuum platter mat? I was thinking of the Vacuum mat produced by Thorens back in the 1980s. Now kind of rare, but interesting.

-Steve

Lew, on a side note, both a Krebs modified Sp10Mk3 and factory stock Sp10Mk3 reside here currently, although I personally have yet to directly compare at length.