Direct Drive vs. Idler Drive vs. Belt drive

@thuchan , the need for an all air design became obvious when I attended a manufacturer’s rollout for the big new Technics. They had a naked motor available for admiration, and so I picked it up, put it next to my ear, and I could hear the sleeve bearings when I twisted the spindle. Not loud, obviously, but the noise was there if you listened carefully. My New Way amorphous carbon thrust bushing is dead silent!

terry9,

Did you install that air bearing on the main platter bearing?  Is the motor that drives your set up similarly equipped with an air bearing?  

@larryi , I installed that New Way thrust bushing on a platter board which is isolated from the motor. Technology is belt drive - as others have noted, anyone can build a belt drive in his workshop. 

Alas, I could not find a low power, ultra-low-noise motor with air bearings, and I have not got around to replacing the sleeve bearings with air. It’s pretty fiddly!

But those sleeves are a problem. This is demonstrable by removing the belt and manually bringing the platter to speed. The latter sounds more refined, less high frequency hash. When the belt is restored, hash returns. When the motor is turned on, nothing changes. Hence it is the motor’s sleeve bearings to blame, not cogging or other electro-mechanical effects.

This is a little surprising, given the platter's mass, about 45 kg.

Thanks, that is what I thought.  The motor then has the same issue with noise/friction, albeit attenuated by the isolation provided by the belt.  The New Way bushing looks like it provides effective isolation of the shaft from the bore in the bushing itself, but, does it, or something else provide for levitation of the platter (no thrust bearing at the bottom of the shaft)? 

Also, what do you use to pressurize the bearing?

I applaud DIY efforts to to build something new, or improve upon an existing design.