How important is low W & F performance anyway?

@elliottbnewcombjr 

"The tolerance of the housing and bearing shaft were so fine that an air spring was created, it took several minutes for the air to get out and the platter/shaft to descend fully. I’ve never forgotten that precision."

Even inexpensive bearings work that way. I remember first setting up my Revolver Rebel turntable decades ago, after squirting the premeasured lubricant from the syringe the manufacturer provided and dropping the spindle into the bearing housing, there was very long period of settling of the shaft, might have taken up to an hour if I recall and the manual cautioned not to touch anything while this was happening since it might damage or score the assembly.

All Rega turntables go through this during the manufacturing process and the mating parts arrive sealed and protected from foreign matter prior to assembly. These bearings can remain untouched for decades without any maintenance at all.

You should all take a lesson from @richardkrebs.

@faustuss 

this video, assembling a Linn TT in the Bedrock Plinth (it’s not a plinth, merely a frame).

https://www.youtube.com/watch?v=SqP4eHBSlI4&t=2s

watch and listen at 5:15, see the platter and shaft drop like a stone, AND listen, a clunk, what the hell is that?

The motor has four shaded poles, so it is not quite synchronous, instead slipping slightly with the braking effect and stylus drag.  Personally I think stylus drag is tiny compared to the eddy current brake, which could explain why these decks are valued for their ’drive’ when playing heavily modulated passages.

I’ve seen this rationale applied before in the past and it is counter-intuitive to me.  The concept is if you load the drive/platter with torque (either through an eddy brake or thick bearing lubrication), then small dynamic changes in torque will be "swamped"  by the static torque load and will therefore go unnoticed.  If the speed is stable with whatever static load is placed on it, the system is in balance and dynamic loads will still disturb that balance proportionate to the amplitude of the dynamic load, not in ratio of the dynamic to static load.  The only way this makes sense is if the torque load/rotor angle is not linear, which it is not-torque is proportional to the sine of the rotor/field angle, but the relationship is very nearly linear at the lower end of the torque curve.  So unless you are applying a static load that is very near the stall torque (close to 90° rotor/field angle where the slope starts to flatten) it’s difficult to see how this could have any benefit.  I suspect the improvement in sound that some report with thicker bearing oils is due to mechanical damping and not to speed stability.

@phoenixengr. I tend to agree with you.  Viscous pre-loading of the drive can be beneficial as it damps the bearing and by extension the platter. But perhaps more importantly, it damps any tendency of motor to oscillate about the synchronous speed when presented with a sudden change in load, torque demand. 

Cheers. 

I think the earliest version of the 301 did use a grease lubricated bearing which then became the eddy current brake that RB describes.  301 aficionados may correct me if I am wrong.  Some 301 cognoscenti seek out the grease bearing version ahead of the later version.