Direct Drive

@sokogear , Why? A Sota Sapphire with a Kuzma 4 Point 9 is $8000. The Thorens is 1/2 the price. 

Ketchup, I take the bearing as a given for any turntable of any type.  So there is no special problem of a bearing in a DD type.  All platters ride on some sort of bearing.

Mijostyn, I don't know precisely how a Cosmos is constructed, but I do know that  SOTA have improved upon basic design of a suspended BD.  When you mention a "separate platform" for the motor, it must nevertheless be either suspended along with the bearing and platter or fixed in space.  Which is it? How is the platform isolated from the subchassis or shelf?  I'm just curious, not contentious.

You wrote, "Above that frequency such as at pulley speed all vibration is absorbed by the belt. Nothing gets to the platter."  Come on.  Nothing designed by men is that perfect.  The belt is a filter with a certain cut off frequency and rate of attenuation of mechanical energy.

@mijostyn - gotcha. I thought the Sota was around $4K. Also thought you like Schroeder arms. You should be a turntable market analyst/consultant. BTW the record clamp/device I asked you about works nicely, really for thinner or warped records - the Hexmat Molecula. Really it is the only option for light. short spindle tables that strongly discourage putting any weight on the platter. Also, their record isolator (mat), the Hexmat Eclipse, also is an improvement over any other mat I have tried (felt, polymer-Herbie's, and rice paper). They are pricey items, and they make a less expensive isolator, the Yellow Bird, but compared to the price of a good TT, worth considering. I know you are the heavy platter, stick the record to the platter proponent, but I think the isolation of the record barely touching the platter (1 sq. mm surface area makes sense, and more importantly sounds nice.

@sokogear , I am a proponent of Schroder arms. I have one but, the CB is $1000 more than the 4 Point 9 and I was trying to showcase the Sapphire in the least expensive combination I would find expectable. 

Making sense is an assumption. Assumptions are the mother of all F-ups. The record vibrates the stylus, then there is Newton's third law. To stop the record from resonating under the stylus that "energy" has to be dissipated in a much heavier mass by pinning the record as firmly as possible to that mass which in this case is the platter. With the record firmly fixed all that energy goes into moving the stylus which is also connected to a much heavier mass, the cartridge and tonearm which in turn are connected to an even heavier mass, the turntable.  I think the vast majority of turntable aficionados agree that the record should be firmly pinned to the platter and most of the high end turntables have a mechanism to do this.  

@lewm, Correct, the belt is a first order filter so the attenuation would be 6 dB/oct. But, by the time you get up to the vibration generated by the motor nothing gets through to the platter. 

The motor platform or bracket is attached to what Sota calls the cover. The sub chassis which holds the platter and tonearm is isolated from the cover by damped springs with a resonance peak at 2-3 Hz vertical. Sota does not specify horizontal resonance which is certainly higher perhaps 5-6 Hz. The Superiority of the MinusK platform is that it's horizontal resonance is almost as low as it's vertical resonance. The problem with the MinusK  is that it can be a bitch to handle a turntable on it because it is very floaty. You have to be very gentle to keep it from bouncing. The Sota on the other hand is a delight to handle. You can use the cover to brace your hand when you cue the record. You can drop the dust cover and nothing happens. In order to get the record to skip you have to hit the turntable on it's side hard enough to move the entire turntable.  

The next advantage of the Sota is that it uses a magnetic thrust bearing. It is the thrust bearing that generates the most noise as it is subject by far to the highest pressure. 

My real problem with direct drive turntables is the presence of a large oscillating magnetic device right under a very sensitive magnetic device.  Speed wise they can be very accurate. Noise depends on the quality of the bearing. I know of no direct drive table with a magnetic thrust bearing. In the end, stable, accurate speed is stable accurate speed by whatever means. I prefer my motors as far away from the cartridge as is practical. It is an instinctive preference I admit. The requirement for a suspension is not instinctive. I can demonstrate the superiority of suspended turntables to anyone in just a few minutes without playing any music.