SP-10 Mat

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.)

Lew, thanks for your response.
re: mat thickness versus vta/sra. Plus one other factor; the sp10mkII platter has a pocket that a mat must fit within. And to be functional any mat would need to at least show proud of the platter rim. Just noting that part.

In any case vta/sra becomes a necessary adjustment when comparing one platter mat to another. And I keep a number of platter mats around handy just because I like to experiment with these items. Yes, the arm I'm using makes it convenient to adjust vta/sra. And I did make use of this feature during the comparison. But combine with with some earlier comments made to this thread about the BA mats.....that there might be some concern about the carbon mat losing traction against the platter under moments of higher stylus drag / speed corrections, etc. So, with the BA Mat One, its undersize thickness does allow the placement of a layer of "something" that could, conceivably improve traction between the carbon mat and the platter. Just a thought.

RE; BA Mat One and warpage.
1) I'd think that the solid graphite material, if left bare, may or may not be susceptible to warpage. Either during production or at a later date if improper mat storage became a factor. Just a guess. Why not check to see if solid graphite is or is not susceptible to warp.
2) These mats are coated by the mfr with a "proprietary" clear coat of some polymer material. I say polymer because I've held the mat and detected what I perceive to be a minimal flexibility to it. And I suspect that the mat prior to these coatings may not exhibit the same properties. and the coating will keep the graphite from shedding its graphite surface whenever it comes into light contact with.....anything. Graphite; very soft stuff that rubs off.

3) yes I'm certain that the sample I saw was indeed warped. As noted, ~1/16th inch. I observed this while allowing the mat to lay flat against a thick pane of glass that I keep around. and the glass I have proved to be very flat.

4) The mat does not belong to me. It was on a brief loan from another audiophile living in my area so that I could try it out on my SP10 mkII. And I liked what I heard. I'd probably look into a BA Mat 2 for this application. Also, I'm thinking about the benefits of gunmetal copper in this platter. I'm also thinking about any diy mat I may try in the meantime.

5) back to the clear coating that BA applies to these graphite mats. Perhaps during this process, when the coatings are applied and allowed to cure, it could conceivable be possible for the polymer to shrink while it cures / hardens. If applied unevenly.... Just conjecture.

But I did mention the warping I observed just to see if anyone else had seen a similar situation with one of these.

-Steve

I've just received my Mat 2 today. Austin Jackson was very adept at quickly responding to my request for this mat. So far I've had enough time to spin a few albums through. My impressions are favorable as I had expected.

Some early observations:
Yes, it is a nicely flat sample. (see my earlier post to this thread)

Mat thickness. Both the BA Mat 2 and the original SP10 mk2 rubber mat are within .005 inches of the same thickness. Just call it 5mm thick for both mats.

Traction against the platter. The BA Mat 2 is lathe cut from a solid chunk of carbon graphite. It seems to have rather poor traction against the aluminum platter.

And the first evidence I saw of this was while holding a record brush against the spinning record. The brush did stop the record while the aluminum platter continued to spin unhindered.

At first I could not tell if it was the record spinning against the upper surface of the BA carbon mat, or if the BA mat was spinning against the sp10 platter.

I solved this by looking for a means to improve traction between platter and mat. Sparingly, I brushed a small amount of liquid solder flux (rosin based) in an array of spots onto the surface of the sp10 platter. Equally spaced. Not much. Just enough to see if when the rosin began to solidify it would improve traction between mat and platter. And then I replaced the BA Mat 2 onto the sp10 mk2 platter

After this I could hold the record brush against the spinning record and observe that the record did not slow or come to a stop as it had before. It was the mat spinning against the platter.

I expect the small amount of rosin I used to be a benign method. Hopefully I'm not wrong. I'll know next time I need to remove the BA Mat2 from the SP10 mk2 platter.

Listening:
it's early but I've already heard improvements over the standard rubber mat. Firstly, there is an improved clarity in the reproduction of various detail. Inner detail stands out a little nicer. But also macro detail improves as well.

Haitink / Amsterdam Concertbow....Mahler No. 5 on Phillips. Firstly, the horns are reproduced with less blare and more air. Less Glare.

Led Zeppelin II / Classic Records 180g remaster. No loss in rhythmic drive as noted before. No loss in bass energy. No loss in energetic drive. Improvements heard seemed to be a clarity throughout all frequencies...and the improved definition of micro detail such as harmonic overtones. Sustain and decay on the cymbals is very nice. Already nice before but just a touch better now.

Just a few notes. I'll spend more quality time listening to this and write down my observations to my website.

-Steve

Double-sided carpet tape.