Turntable speed accuracy

After reading the posts, I thought it would be helpful to add my experience with a turntable design that is very unique (at least as far as I know).

I have been working for 4+ years on a turntable design that came to fruition recently. The turntable is a rim drive turntable with a super massive bearing (the largest built, as far as I know) and a massive platter. The theory behind this design was to have very high inertia to overcome stylus drag derived speed variations.

I can tell you with great confidence that the design/theory does work as intended. The high inertia platter/bearing combination brings forth drive and rhythm like no other turntable that I have heard. It is quiet amazing.

That said, the turntable is not perfect, as the rim drive motor speed variations need to be tamed. Speed accuracy is not a problem, but minute variations in speed is an issue for now. I have been working extensively with different rim motor solutions, including rim wheel materials, sizes and durometers. Each has there own sonic signature and pros/cons.

IF the motor speed variations can be tamed, then I believe the current design is unmatched. BUT, I am still seeking a better motor solution that I currently have.

Here is another finding that I came across: if the table has a stable the motor speed and has the ability to rip thru transients and not be adversely impacted by stylus drag, then you will discover that your next culprit is eccentric record centers. Wow/flutter derived from eccentricity in the LP will become more apparent/audible.

This is just an FYI and thought it might help in your thinking.

I agree with Banpuku about hearing the effects of record centre eccenticities.
On mt Victor TT 101 DD turntable.....which demonstrates admirable speed accuracy via the Timeline.....I am more aware of this phenomenon on certain records than I am when using the Raven AC-2 belt-drive.

I guess in the best of all possible worlds, your turntable's speed irregularity would combine with your LPs off-center spindle hole to give you perfect pitch.

Thanks, Peter, for your further description.

Banpuku, Have you looked at the TT Weights rim drive or the Trans-fi Salvation rim drive? Each has its strong advocates. Both seem to ascribe to the heavy platter/rim drive paradigm. I have not heard either, but I note that both seem to use a rather small diameter wheel to drive the huge platter(s). On the other hand, the VPI and Teres rim drive(s) use a rather larger diameter drive wheel. Where do you come down on this design choice? No doubt you've given that a lot of thought. Just off the top of my head, I would have thought that the larger the circumference of the drive wheel, the better, right up to where the diameter of the drive wheel would equal that of the platter.

Lewm ~ I have the TTWeights rim drive and the Timeline shows it does not have speed stability, this on 2 different TTWeights rim drive models. Does it sound OK? Yes but when I now listen to a DD table I can clearly hear the difference.
(dealer disclaimer)

Dear Skos, You are preaching to the converted. I am a confirmed DD junkie. I still do like my highly modified Lenco, however. I was unable to test it with the Timeline, because the spindle hole in the Timeline is too small to admit the spindle of a Lenco (or of my Kenwood L07D). This to me is a major oversight in the design of the Timeline, as I think it would have been easy to supply alternative spindle hole pieces for it, especially at the price. (I could imagine a removable rim-threaded bottom puck; three such pucks could accommodate all typical spindle diameters, with a snug fit.)

I think I remember your earlier posts on the TT Weights. It appears that their drive wheel and the rim of the platter have been re-engineered in their latest models or their revised older models. Perhaps those issues were resolved.