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Tables That Feature Bearing Friction

I recently had the opportunity to audition the DPS turntable which, unlike most tables, has a certain amount of friction designed into the bearing. This, when paired with a high quality/high torque motor, is said to allow for greater speed stability--sort of like shifting to a lower gear when driving down a steep hill and allowing the engine to provide some breaking effect and thus greater vehicular stability. I am intrigued by this idea and was wondering what other people thought about this design approach. Are there other tables which use this bearing principal? One concern I have is that by introducing friction you may also be introducing noise. Comments?
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dertonarm
1,042 posts
 
The only turntable so far which did it right (i.e. - correct application of "friction" to stabilize movement AND to provide additional damping to the platter) is/was the old venerable Platine Verdier in its original form (pre-1992) of bearing (without the ball support). Its a true eddy-current brake applied on a large diameter and fairly strong. The large diameter provides excellent damping on the turntable platter itself (which however was only a side-effect of the vertical bearing being suspended by magnetic force). Somehow archaic in execution, but very effective indeed.
dan_ed
2,451 posts
 
Dertonarm,

the only table? Really? Perhaps you should try to listen to more 'tables. ;-)
larryi
4,047 posts
 
This is an interesting discussion, thanks to all. It seems to be the case that some other manufacturers take a quite different approach. Nottingham, for example utilizes an extremely low torque motor, so any kind of breaking is out of the question.

I have no idea myself what are the merits of any particular design choice. All I can say is that I have, and like, my Basis Debut table and I have, and liked some of the others mentioned.
dgarretson
2,599 posts
 
On a related point, one thing I've been wondering is why not integrate a flywheel with the motor pulley. For AC motors in particular this would have the advantage of smoothing out cog noise at the motor source, rather than pass it on to the platter(or an outboard flywheel) through the drive system. I know some of the older heavy-duty high-speed motors have some built in flywheel effect; it's surprising that this approach is not taken with some of the smaller motors in current vogue.
dertonarm
1,042 posts
 
A flywheel can very well create problems if not done the right way.
It is only suitable to motors featuring a solid axis shaft and a very good and rigid bearing. The flywheel - if done the right way - add considerable amont of inertia to the motor shaft and to the whole moving system. Therefor it requires solid construction. Especially if the flywheel is directly attached to the pulley or part of it (which is the only way to use the inertia moment of the flywheel to smooth out most imperfections of the motor itself). The smaller motors envogue right now do not fare very well with flywheels.
The small motors common today have 3 big advantages. Even if all turntable-manufacturers using them do list some other advantages, it all comes down to these 3 only....:
1. they are inexpensive.
2. they are inexpensive.
3. they are inexpensive............
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