SP-10 Mat

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.

I have an Artisan Fidelity SP-10 with upgraded copper platter. I've found George Merrill's GEM Dandy cork mat to work very well.

Td, That's the first I have ever heard of a Boston Audio Mat being warped. Both my Mat1 and my Mat2 appear to the eye to be perfectly flat, and certainly there is no tell-tale sign of warpage when they are spinning. I trust your judgement, but be sure there is no other possible cause of your perception that yours is warped. If it IS warped, BA should take it back and exchange it for no cost, IMO.

One other thing: Why do you deem it to be so important to maintain the exact same thickness as the OEM rubber mat? A slight tweak of your VTA should take care of any minute difference between the BA and the OEM mats, and placing the rubber mat in between the BA and the bare platter will probably alter the sound, for good or ill.

Considering the materials of which they are made, I cannot imagine a BA mat warping post-manufacture. It could conceivably have been warped as a manufacture defect, I guess.

Chris, would love to know what you think of the two Mk3's, with vs without the Krebs' mods. (Of course, there are nothing but positive reports from other sources of which I am aware.)