analog newbie question/vinyl weight

Luke,

Be aware that using the weight/thickness of an LP to estimate arm height is only valid when comparing LPs on the same record label (and from the same pressing plant and era). Different plants and engineers used different gear and adjusted it differently. Therefore, cutting stylus SRA's vary widely between similar weight LPs on different labels. A 180g Decca/London will not want the same arm height as a 180g RCA or Mercury or MFSL reissue. Not even close.

We use weight (as a proxy for thickness) just as you're planning to, but only within the context of a single record label. We have a baseline setting for a typical weight on each label, then adjust for different weights from there.

That's still just an estimate of course. Fine tuning for each LP is by ear.

Doug the Luke method is the only real way to get it right or i should say get it to sound right to your ears.

I sent in my TP last month for a check up and on return decided to spend the time to listen for those changes from different VTA/SRA settings since i was starting from scratch. In the end my previous settings were high with arm height, and i knew UNIverse likes in low in the back. I listen to blues and classic rock mostly and like a sound thats more on the bright side of things. To my amazement you dont loose that nice tingly sound when you lower the arm instead you get that and better mids, bass, stage and sound thats fantastic/more seamless. The funny part is i thought my setup sounded good before i sent my TP in go figure.

I love vinyl playback with its hands on routines what i needed to learn and after 40+ years of hands on, you should never think you know it all and sit pat.

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.

Just off the cuff.. I think changing the record height or thickness will change the SRA much more than changing the pivot height a similar amount. It is early though.

I'd say one millimeter is one millimeter on either end, and change in VTA is a change in VTA. For simplicity, if you started parallel to the record surface, I don't see how one millimeter on one end could result in completely different SRA than one millimeter on the other end, except that they would work in opposite directions. But I've been listening till 5 am and doing extensive damage to my Scotch reserves so someone with a clear brain please chime in.