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
I think the correct term is "bearing drag", not bearing "friction". Friction would implicate 2 surfaces contacting each other and if that was the case there would be no place for oil, and as such, you would have a very noisy bearing.
Furthermore, a well made bearing would have a hardened shaft, be cylinderically ground, and the bearing housing would be honed to accept the rotating shaft with perhaps 0.0001"-0.0002" clearance at most.
Dear Frank_sm, if you look real close, you will find that almost ALL bearings in turntables ( not just the old Well Tempered Turntable ...) AND gimbal bearing tonearms as well as ALL pivot tonearms do indeed consist of two surfaces contacting each other. Most of these do feature oil to lubricate the bearing and to decrease wear and noise - but in the end (aside from magnet bearings, pure air pressure and oil pressure bearings ( and all of these have to be horizontal AND vertical )) almost all (NOT all.....) bearings in use in audio components do indeed feature surfaces ( 2 or more..) contacting each other.
Dertonarm, magnet and air bearings also have their own drawbacks. Magnet bearing a'la Verdier bears the platter weight with no friction but features conventinal journal bearing, which is more loaded, and most importantly less evenly loaded due to inherent instability of magnetic repulsion system: magnets are trying to slip sideways with the side force increasing as the deviation from perfect concentricity of the two toroidal magnetic fields increases. I'm not familiar with any other magnets arrangement addressing lateral instability, do you?
High pressure double air bearing (vertical and lateral) is near close to perfection, providing compressor noise, water condensation, air contaminations and pressure fluctuations problems solved. In addition, it shall provide possibility to safely "land" the platter in case of sudden pressure loss, otherwise axial bearing may be easily ruined. This is the first rate engineering problem by itself, bearing in mind very small air gap.
What do you think about hybrid bearing: magnet axial bearing combined with air journal bearing for lateral stability? Sounds crazy complicated, but who cares?
Dear Livemusic, I have been involved in lateral/vertical air bearing for 5 years and given an air bearing with a large number of individual "openings" - a sintered material for instance - there is no problem with "safe landing" in case the air supply breaks down. Water, dust and micro particles, fluctuation and pump frequence are problems all solved long ago in todays high-end air-supply applications with the approbiate technical applications (3-way filters, surge tanks, air dryer etc. etc.). The vertial magnet bearing is applicated in the Verdier for several reasons.
That it still do feature a conventional lateral bearing - well, why not?
Today I see the most potential of improvement for high-end turntable bearings in oil-pressure conical bearings.