Direct Drive vs. Idler Drive vs. Belt drive

Yes, this is an advantage of a DD drive that is often overlooked. There is no horizontal force induced by a belt, thread, tape or idler wheel.

There is a toppling force if the thrust point is at the bottom of the bearing but this should be easily absorbed by a properly designed bearing. 
Invert the bearing with the rotating mass centre of gravity at the pivot and this force goes away as well. 

There is then the obsession with micro polished shafts. It might look great but technically it is sub optimal in an oil lubricated bearing. We want to maintain a continuous thin oil film. This is best achieved by a microscopically dull shaft surface finish which captures the oil film. Built properly a bearing like this has only the thrust pad as a contact point. Since this point has an extremely low radial velocity due to the small contact area, it can be made to be very quiet. Any noise in the bearing shaft/sleeve area is the shearing of the oil itself.  

cheers.  

In belt drive, you need to have everything ideal, otherwise the speed is floating.
A freqsion of needle, and bearing decrease the speed,  the motor doesn't control the platter but tries to hold a speed constant and it makes a belt tension change and speed oscillation.
Every small change of belt tension, material, width change sound dramatically.
Bass has rubber, soft sound, PRAT is broken. For classical music, especially piano music or fine rhythm jazz belt drive completely kills rhythm details and changes music for unconnected set of sounds. 

I respect all drives and am adamant they all have there strength and weaknesses. All have the ability to play quietly and appeal to the INDIVIDUAL'S preferences of what THEY believe is right for them. All of you that are biased closed minded to ownership not only ignore strengths , popularity, but embellish all faults of each in a general broad attacks not serving the truth to the improvements specific brand and model have.
Many inverted quality bearings in design and applied with a weighted platter show zero horizontal pull much less rubbing the spindle. General statements of ignorance not fact are common with all biased ownership rants. There were and are are an awful lot of horrible DD tables made not just the very very few better ones. Something few of you immerse in the generalized opinions paraded as facts.
Same as many belted units are sub par but far from all and idlers do indeed have a need of massaging out self noise. 

The final sound followed by users visual appeal is all that's important. Not what one or two gregarious opiners of one drive think here. Like when specs are brought up and championed, yet the fudging of how those numbers were done in Japan, a well known fact is left out. (Weighted )

Vinyl is a great medium for those that appreciate it and what it can bring to music. Bashing users like Rega owners who like the prat and prefer simpler less fussy of plug and play is childish. It would seem to me, inclusiveness would be a better way to respect choices and to learn. Being that guy that can only praise what he owns and shade anything or anyone else that doesn't fit their narrow view and generalized ignorance is killing interest and the participation in these forums.

It's not a simplistic obvious fact which is better. Its a choice in preference of appeal to tone and timbre, degree of difficulty and ability and willingness to achieve it ......and like it or not estetics are a key to most for appeal as part of the draw. I find it amazing what some have done and produced in all drives to better the playback and reduce drawbacks. The negative biased drivel of anything other than what one narrow mind owns here. ...not so much. Enjoy the music, respect the individual and his choice....after all. ..its opinion in the end..

Miyostin,
you are right comparing air bearing and magnetic designs.
nevertheless what counts are bearing hardness, batch braking moment and energy transmission by the bearing.

E.

has2be

I was merely (re)stating an inherent advantage of a DD design with respect to its bearing, after all the OP has asked this.....
"I'd like to know your thoughts on the strengths and weaknesses of each drive system"
I did not say that overall DD is superior. 

An inverted bearing is inherently more stable, on that I hope we agree?
My comment about the shaft finish is simply engineering 101. In the outside world it is common to not polish a sleeved oil lubricated bearing. This for the reason I raised. I know of one, possibly 2 TTs that use the non polished technique, both have well designed and engineered bearings. . These are the Final Audio Research and the big idler EMT. These TTs have very quiet bearings thru good engineering not bias 

Sure you can remove horizontal pull on a BD  bearing by having 180 degree opposed motors or an idler. That said, one would need to be very careful not to introduce noise into the platter from the second (or third) rotating element.

All TT drives have strengths and weaknesses, there is more than one path to enlightenment. On that we agree. I prefer DD, that is my opinion, others do not. I'm fine with that. 

 My experience is that it is by far the hardest to achieve good performance from a DD design. This because there is no filter between the drive and the platter. Any aberrations in the drive are exposed warts and all. This is particularly difficult if the designer chooses a high motor torque to platter inertia ratio. Difficult but not impossible. 


Cheers