Tables That Feature Bearing Friction

Lewm, regarding my belief in Dertonarm's contentions... if you look at the first paragraph of my second of two consecutive posts above, I state...

I, for one, am not at all convinced Mr. D is right (though I would love to listen to the table he created) about high mass BD (even though my preferred TT at home is a HM BD with slipping thread drive). I expect DD is probably 'better' because I expect it is easier to control the electromagnetic slippages than the mechanical ones.

Regarding Chris Brady's DD TT... in paragraph two of the first of those two consecutive posts, I state...

It is obvious through Chris' assertions here that he believes his new DD system, and perhaps others', improve(s) upon those highly-praised BD TTs). I am sure they do.

I, for one, would love to have the chance to listen to that TT. I am sure it is fabulous. All the anecdotal evidence points to a conclusion that he has made one of the top commercially available TTs out there. But your next point:

Rather, these are good data that have to be explained.

is the crux of what I was trying to get at. I believe that Mr D's point is that anecdotal evidence of one or two commercially available TTs sounding better than another couple of TTs is fine, wonderful, and nice, but beside the point. He has asked for technical arguments WHY DD should be less of a compromise when attempting to create the perfect TT and so far noone has come up with the technical arguments, the physics, or experimental results detailing why that should or could be so. I think he would welcome the philosophical debate. I know I would.

And yes, I think the escape clause for most of us will be to say that we haven't heard the best BD TTs or DD TTs out there. But again, for Mr D, that is beside the point. I may not agree with his assertion that high-mass thread-slippage BD TTs are the best method to approach perfection, but I have no science or experimentation to back up my disagreement, so instead I hope to learn.

Cheers,

Dertonarm:I knw that is more easy in this way because you don't have the precise-scientific information/tests on the " neutral " build materials that are very important part on any TT build/design. Yes I know your answer: futile.

Regards and enjoy the music.

Indeed Berlinta, you did not get a direct response.
You did not ask for it either.
I layed out all the points the days before. I could again answer to all the points in your last 4 posts. But I do not see any attractivity to repeat myself over and over again. All the answers were already posted in this thread before the questions came up.
It will not be to the benefit of this thread - especially not right now as it is finally back to technical discussion again - if I post direct response. Rereading some of my earlier posts will show that the answers are already there. They just got "buried" in the interim when the discussion left the original intend.

I do have a file - 3" thick and 8 lbs heavy - of extensive test and data sheets to about 5 dozens different materials which at one moment or another were part of the turntable design pre-thoughts (some finally made it). However I remember that one particular poster stated yesterday:
"I don't need that you convice me, normaly I take the steps by my self to convince me about any subject that has interest on what I'm trying to achieve."
I respect that position.

Air would be a poor choice for a drive mechanism since it is compressable. Hydraulic fluid on the other hand is not compressable. Driving the platter with hydraulics would be an alternative choice. A pressurized bearing could also be utilized.

I'm not a turntable expert, just a bmw tech. I believe some models of Jeep/Chrysler used hydraulic cooling fan motors powered by the P/S pump due to the fact they are quieter. Perhaps a similar system could be made for a turntable? Just throwing out ideas.