Over on Lenco Heaven there is an individual who sells copper mats (SCuMat) his name is Sien and he posts under sph. I purchased one his bearing a few years ago and a SCuMat last year, both transactions were flawless but there is wait time in-between batches. I also agree with other posters who say combing and experimenting with different mats can lead to positive results...
I have purchased an Oyaide BR-12 for my Technics SL-1500C which arrived yesterday, and what amazed me is how if completely flattened out a warp I had on an album, even without a weight. Plus, it has certainly firmed up bass notes, quite apparent. I haven't readjusted the VTA yet though which I think I need to, and maybe the azimuth, as the right channel now seems to be a little more dominant.
Any ideas about how a platter mat can flatten a warp? Seems unlikely that simply placing an LP on a platter mat of any kind could make a warp go away.
The mat is slightly concave on purpose and meant to be used with a clamp or record weight. It can help mitigate the effects of warps but does not eliminate them IME.
I put an album on that had a noticeable warp when I used the stock mat, when I used the Oyaide, the warp wasn't there.
Swapped out the Achromat on my 1200 to try the Oyaide BR-12 and really like it. Not sure if I necessarily prefer it to the Achromat, still deciding. Mind I'm using an Orsonic clamp.
I just received a used Technics RGS0010 6mm mat from an eBay seller in The Netherlands, and it looks as good as new and I couldn’t be happier with the sound quality and the VTA adjustability with my SL-1200GR. I wonder why Technics doesn’t supply this mat or something similar in 6mm as a stock mat.
Well to each his own. I use the Music Hall Mat on top of three Oyaide BR-ONEs (necessary to achieve the right VTA at the lowest setting of the arm, as the Music Hall Mat is thin). I'd like to try the Oyaide BR-12 though. The Music Hall Mat is also slightly lower in the middle than on the edges, but I use a weight and it works fine.
BTW, the Music Hall Mat is more like a cross between cork and rubber. It's not your typical hard cork at all, but more like some type of cork hybrid material. The design is that the record is lifted off of the mat (and only air is under the record except for small round lift pads on the edges. Playback is very quiet with no static.
I have the Herbies Way Excellent Mat II 4mm on top of a cork/rubber mat on my 1210 mk2, solves the vta problem and sounds great.
Any reason not to use a leather mat? I have one and it works fine with no static or slipping. Really looks nice and is easy to notice if needs dust removed as it is black. Have not found any downside to using it as top mat on my GAE. Others with better hearing might disagree.
Another nice rubber mat is the Ultima THT-291 from Tokyo Bouon (Tokyo Soundproof). It's made from hanenite rubber (HANENITE | 内外ゴム株式会社 ), which is used for vibration control in some very high end audio products, such as the $4700 Audio-Technica AT-SUT1000 step up transformer, and is reasonably priced at around $35 from Amazon Japan ($50 with shipping). It's 291mm x 4mm and weighs 330g. I bought one recently to use on my Micro Seiki DD-40 so don't know how well it works on the Technics, but very nice mat...