Dear Banquo, Your remark directed to Halcro speaks honestly to one point I have been trying to make with the plinth-less crowd. The torque of an SP10 motor (Mk2 OR Mk3) is sufficient to move the chassis, if the chassis is unfettered by a plinth. Thus I would fear in theory what you may be observing in fact, that your turntable may be able to "walk" away from correct alignment. I think this is fixable by maybe using double-sided tape between the bottom of your chassis and the top surface of the AT616 footers. Of course, I personally would fix it by building a plinth or some sort of substantial anchor for the chassis. I recently read that the servo mechanisms in these turntables apply full torque instantly, each time they are triggered by a speed variation. Heretofore, I thought the motor controller via the servo system could call up "just enough" torque to return the platter to correct speed, when needed. If that were true, the effect of torque to move the chassis would be minimal during actual play. But now that I have learned that the servo simply gives a full on or full off signal to the motor, I am even more convinced re the value of a good plinth. By the way, I did not mean to imply that you (personally) were dogmatic re AT616 feet, but there seems to be a general trend in that direction among other disciples of the Copernican approach.
As regards the tendency of an LP to slide on the surface of a Boston Audio mat, I have observed the same thing. I use a Mat1 on my Lenco. The Mat1 had a tendency to slip against both the surface of the platter underneath it AND against the surface of any LP on top of it. I finally cured the former issue by inserting a few slivers of double-sided carpet tape between platter and mat. Just small pieces were sufficient. As regards the tendency for LPs to slip, I too notice that when using a carbon fiber brush to remove dust from the surface of an LP prior to play, but it does not seem to be an issue during play at all. You might want to try an SAEC mat; they are often for sale on eBay and Audiogon for around $300. No slipping issues with SAEC. But based on what I hear from my Lenco, I think the Boston Audio mats may be (even) more neutral sounding than the SAEC. After hearing either one of these mats, I could never go back to the OEM rubber mats. And I am sure there are other candidate mats that would best the OEM ones. This was very true for my Denon DP80 as well. The OEM Denon mat might be even worse than the Technics one. (Alas, the Denon sits, loved but unused, on a shelf in my basement.)
Dear Ecir, Idler-drive turntables need to be mounted in well built plinths for best performance, IMO. I think that is much less controversial than the use of a plinth with a direct-drive. I don't think you will ever get the best out of your Garrard without some sort of plinth.
