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
Well, we do not have to re-invent the wheel here. All this research about suspension has already been done by industry with huge amount of manpower and technical resources. These problems are solved.
We just have to apply them to the turntable system and/or its benchtop / stand platform.
The only problem is: they do not come cheap (as any "good" turntable cannot come cheap....) .......
Have a look at the website of Minus-K and/or Kinetic systems or any of its market competitors.
What will do the work for an electron microscope will do the work for a turntable.
The better of these benchtop platforms will isolate from vertical AND horizontal vibration.
Foot-falls and usual household vibrations from washing machines and in-house motors are not the problem.
The problem is the all-present buliding resonance.
It was an eye-opener for me to actually "see" what isolation from enviromental vibration really means - and what it can do.
If we can agree, that the idealized working conditions are very similar for both turntables and electron microscopes (both "working" in very similar nanocosmos dimensions) - then we already have the solution.
In easy words: you do not have to worry about suspension at all if you put the turntable in question on top of a professional vibration isolation benchtop platform precisely resonance-adjusted to the weight of the turntable in question (and for god's sake - do NOT place any standalone/detached motor-drive on the same platform!).
Borrow one or try to get one from technical scavangers (there are enough companies around selling of the remains from technical-orientated companies getting out-of-business). I bought a good benchtop from Kinetic used via ebay for 1/20th of the list price (o.k. the transport from North Hollywood to central europe was a few bucks too, but not that bad).

Well - a really "good" new isolation platform will cost the same as any of the "avarage" turntables alone.

If the technical aspect and waypath alone are not enough proof, I recommend to all (for once..... to support the technical outline) following Raul's advise: listen to it.
The immediate apparent difference in sound-presentation will tell the story.

As I still am sure that we do work with techincal facts and issues only in the design of a turntable - the turntable "done right" will never come cheap.
If you are into off-shore boats or high-end rifles or high-end motors - no matter where - if you are looking for the "best" in those they won't come cheap either.
You just can't fool around with physics.
In the design of those topics just mentioned - are we dealing with taste or guesswork ? Maybe in the outlook, the cosmetics - but never in the technical design.
In turntable technical design (NOT cosmetics or appearance) its all physics - and honestly, there are moments when I do not like that fact either ........
Thanks for the info, Dertonarm . . . I enjoyed reading about these products.

But it's not a matter of "re-inventing the wheel", its a matter of understanding the exact requirements so as to make sure we understand how well the solution fits the application, and the problems we're trying to solve. Because (to use a silly example), putting your tomato plants in the finest laboratory glassware doesn't mean their fruit will taste any better.

Most of these off-the-shelf devices (i.e. the MK26) appear to have a low-pass characteristic that somewhat resembles a Chebyshev response, which trades some pass-band ripple or peaking for increased performance in the stop-band . . . I'd speculate that this is an excellent trade-off for most of the laboratory applications for which they're sold. But for a turntable, the low-frequency peaking of these products may indeed cause some problems. I'm sure they still sound excellent . . .

. . . but if you truly want to do a turntable "right" as you say, then simply sticking i.e. an RX5000 on an off-the-shelf Minus-K platform doesn't cut in my book. Using existing laboratory-instrument technology might be a good approach . . . but if you want the BEST performance like you say . . . a custom-designed product that had its stopband/passband performance tailored specifically to a turntable application is what you should be after.
Dear Kirkus, - well a Micro RX-5000 on a (specified for the Micro 5000's weight load) Minus-K is already a different beast.
The one vital point is, to really use a platform only, which is specified for the exact weight of the turntable in question.
One problem is however, that all the benchtop isolators do only perform their best with fairly heavy load (at least heavy for a turntable...).
As the better ones are designed to work with fairly big (= heavy = expensive...) microscopes and similar costly technical measurement equipment (= the users have little limit on spending extra to get their instruments show their best....... as always - they are all "in it for the money"...).
However your proposal to carefully tailor laboratory-instrument technology hits the point. It is exactly what I am doing in my spare time the past 2 months.
Dear Kirkus: I agree with you on the subject.

A TT design are develop on many " factors/characteristics " that have an intimate relationship that makes almost impossible to build the " perfect " TT and like in almost any audio item design we have to choose the best trade-offs and these trade-offs are the ones that make " the difference " but almost every TT designers have its own trade-offs priorities and to be more complex that TT designs comes to a different customers that have its own sound reproduction priorities.

Yes, we can make a TT design near " perfection " according our own technical trade-offs and the ones are not so technical but that have some kind of influence.

About, isolation: how can we aisle the TT from the SPL of speakers in the room?, maybe looking for the lower SPL in that room or taking the TT in a different room where means a different kind of trade-offs. In a TT " perfect " design we have to think about and in many ther obvious factors and other no so obvious ones.

Here we are talking on macro-isolation but there are micro-isolation that are way important too, we have to remember that the cartridge is a very strong " micro ". You point-out the importance of the arm board and I can add ( example ) the importance of a TT mat and we can go on and on. Interesting.

Now, we can put the best technical know-how on the TT design but we have to test on laboratory ( truly expensive ) and in a second step ( critical ) we have to test it in our own laboratory: ears/brain, not an easy task, each one of us has a different " approach/attitude " in the same subject!

Thank's to those human been " differences " exists different/many TT designs out there, good thing.

The subject is how the TT designer can improve ( near perfection ) its own design, it want to do it? are enough TT customers that could pay the price for that " near perfection " TT to make commercial business? can the market/customers understand the advantages on that " near perfection " TT?, I think that exist too many questions and too many different answers to each one question.

As we can try to go " in deep " on the subject as more questions come " alive " and this is almost with any audio item design.
I know ( like Detornarm ) what I'm talking about because in our Phonolinepreamp we already be " face to face " with all those " problems/trade-offs " ( and many others ) and we stay right now in our tonearm design: complex for say the least

Regards and enjoy the music.
Raul.
and that's is " simple " task because there is only one person on the design but what if there are two-three-four persons on the design and everyone with the same " right " to make an opinion valid.
I know the big " trouble " here because some times in the design one or more opinions goes against each other and we have to be very very open mind to make the " final " decision on the subject below discusion. Not easy at all.

We " face " many other issues: exist the technology to build what we " think " on the design ? are there the build materials/parts in a precise way we need it? can we manufacturer if not?, questions/answers like these have its own trade-offs.

The design/build of any audio item is a real and hard challenge for everyone but big corporations like Matushita Harman and the like.

Regards and enjoy the music.
Raul.