Interesting thread and interesting comments how different vinyl thickness effects VTA and subsequently the sound. Reading Fremer's piece in the June 2010 issue of Stereophile, a difference of 1mm in record thickness has an insignificant, if any, effect on VTA and therefore sound. I quote:
"A change in VTA as small as 1 degree requires a rather large (4 mm) vertical displacement at the pivot point of a 9" tonearm, which is why one online story, about using the thin shims included with the Ringmat system to 'fine-tune' SRA, is sadly misinformed. Use of all eight of the supplied shims and the total height change is 1.255mm, which represents a change in SRA/VTA of about 0.29 degree for a tonearm of 239mm effective length. Sorry, but once you're properly locked in at 92 degrees [he's referring to SRA], you're unlikely to be able to hear a difference of 0.3 degrees!"
Since the difference in thickness between a 100 gram and 200 gram record is 1 mm, this should have no real effect on VTA and therefore sound. This begs a question what those who claim it does have an effect and adjust VTA for different vinyl thickness actually hear.
"A change in VTA as small as 1 degree requires a rather large (4 mm) vertical displacement at the pivot point of a 9" tonearm, which is why one online story, about using the thin shims included with the Ringmat system to 'fine-tune' SRA, is sadly misinformed. Use of all eight of the supplied shims and the total height change is 1.255mm, which represents a change in SRA/VTA of about 0.29 degree for a tonearm of 239mm effective length. Sorry, but once you're properly locked in at 92 degrees [he's referring to SRA], you're unlikely to be able to hear a difference of 0.3 degrees!"
Since the difference in thickness between a 100 gram and 200 gram record is 1 mm, this should have no real effect on VTA and therefore sound. This begs a question what those who claim it does have an effect and adjust VTA for different vinyl thickness actually hear.