Turntable speed accuracy

Hi Dertonarm, how in the heck can a bearing for a table cost so much?

Dev, Just read what Dertonearm is asking that bearing to do. (Did you take note of the 110-lb platter?) Then imagine the special tooling and labor required to make the bearing in very small numbers. Then you will understand the cost. Based on typical ratio of parts cost to retail price in the audio business, DT's turntable will have to cost around $70K, just to justify his use of that bearing.

Hiho, I am actually glad I did not know all those details about Papst. I have enough useless information cluttering up my mind already. Sherlock Holmes told Watson that the reason he did not know about Copernicus (or some other well known related body of knowledge) was that he had otherwise to keep in mind the appearance of the ashes and the distinct odors associated with 170 different kinds of pipe tobacco, in order to do his sleuthing. I have never owned a tt with a Papst motor, and I don't aspire to, so no need for me to know anything more than what I have learned by casual reading.

I and several others have been waiting for nearly 2 years for Mark Kelly's motor controller for Garrard and Lenco. I am not holding my breath. This is not to say that Mark is not a completely honorable and brilliant guy; he just has a lot on his plate to distract him. It will be worth the wait, I am sure, once it is done.

Lewm: "no need for me to know anything more than what I have learned by casual reading."

That's very zen. I need to do that myself. Bill Belichick has a sign at his team facility that says "Ignore the noise." Good advice.

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Hi Dev, the bi-planar air bearing for my turntable in the 1990s was only about half the cost of this new one. But this new one has much tighter tolerances and will do the same job with 1/3 the air volume of the former.
In all engineering the cost/performance ratio becomes a steep curve towards the most tight tolerances, as the manufacturing effort and production reject rate rises in a much higher rate than just proportional.
As said before - there are a lot of good quality bearings out there for a fraction of the costs, suitable to provide very good bearing for a high end turntable.
The turntable using this bearing ( plus the USD3500 dental/medical grade compressor needed to run it ) won't ( can't ...) be a commercial product anyway.
Cheers,
D.

However, he did also comment that with a true 3-phase AC synchronous motor controller (so you can throw away the phase-splitting capacitor), the Papst would have been MUCH quieter and therefore might outperform the Thorens motor in all other respects. So, Ralph, have you ever used such a motor controller with your Atmasphere [sic] 208 turntable?

Hi Lew, If the motor was noisy then its likely that there was some sort of defect. All I have ever heard from them is a hiss related to the air moving around the rotor. In my application it is isometrically mounted, so noise simply isn't an issue. What I have heard about the controllers is they are used to get greater stability than the AC line offers, but I am dubious about that- the AC line is quite stable!