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?
128x128dodgealum
Hi Dan_ed, nobody else aside from Jean Constant Verdier did combine these three effects with one very simple device (two magnetic rings of large diameter (in fact former Focal 15" woofer magnets pre-1990 vintage):

- a true eddy current brake on very large diameter to stabilise the movement
(which in fact is not really bearing friction, but acts in that way WITHOUT any noise added).
- vertical bearing elevated by magnetic force.
- further vibration damping on large surface-diameter of turntable platter (underneath) by magnetic force.

That is all I meant.
I have yet to see another turntable offering these three technical aspects with one simple design feature.
The thread was about bearing friction being applied to stabilize movement. Not comparing turntables regarding their "sound".
Here is one TT doing this AND combining the measure to achive some very nice side-effects.
I am certainly not going into any discussion about sonic pros or cons on this or that turntable.
I would be fruitless anyway.
This is - as always in audio - a subjective field alltogether.
My comment is about unique technical features being combined.
In no way do I want to promote the Platine Verdier here (especially so, as the current model no longer do indeed feature these 3 merits in the way the vintage model does).
There are several TT designs with good points and decent performance around.
All have their merits - all have their flaws.
Thats all.
Dertonarm, Are you saying that the vertical magnetic suspension of the La Platine per se simultaneously offered a form of eddy current braking of the rotation of the platter in the horizontal plane? If so, why would that not also be a feature of the current version of the La Platine? (I am going to check my physics books to verify that such a phenomenon would occur, but for now I accept the principle, if that's what you meant.)
Lewm, two magnets rotating in a horizontal = planar sphere do indeed produce an eddy current field.
The Platine Verdier folks and dealers will hate me for this .......anyway:
The current La Platine does feature somewhat lower quality magnets (compared to the old Focal magnets used till 1990/91 - that particular magnet was no longer available when Focal changed to the "6-tablet-magnet" - design invented by J. Mahul for the 15" woofers in early 1991) - thats why they promoted the ball to be inserted in the top bearing shaft hollow. To stabilize the vertical movement of the platter (in mid-90ies production was a tendency to instable magnetic field and often in loss of magnetic force causing many Platines in europe (and I suppose elsewehere too) to "oscillate" (= being unstable in height of platter)). To solve this problem the "top ball bearing shaft" was introduced (well, the hollow was there before, so they just put in the ball - smart move). That particular problem never occured with pre-1991/92 Platines. However the eddy current brake effect is no longer as dominat as it was in the original version with much better and more homogenous magnets.
Thanks. Very interesting, indeed. I do recall hearing rumors about La Platine platters "falling down", due to loss of magnetic field strength, but none of my (two) friends who own the table have had that problem. There are a few other brands that now sport magnetic suspensions, but as far as can tell from photos, none of those has magnets of nearly the same size as found even in the current La Platine. Nor are the platters as massive.
As to my knowledge all La Platine Verdier sold after 1995 do already feature the ball supported bearing. So those can't actually "fall down", as the vertical position is already determined by the ball bearing and no longer by magnetic force. The Platine verdier was imported and introduced to the USA fairly late (it was originally a DIY-project presented in french L'Audiophile magazine (with detailed schematics and description how to built) in the late 1970ies and the first offical built retail version was tested in summer 1980 in a german magazine). I do not know, whether there were any Platines delivered to the USA via the offical importer before 1995.