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 Raul . . . were you able to get any comparisons of stylus drag between a modulated and an unmodulated groove? I think that's one of the central points of most of the discussion of stylus drag.
Dear Dertonarm: +++++ " If the NASA had handled the Apollo - Mission that way, man would have never set his foot on the moon. " +++++

there is no single doubt about, everything must be " perfect " for that " job ", you can't have/make mistakes or " guesswork ".. science is the law.

In the analog audio " stage " science is still the law but the analog " world " is an imperfect one ( everywhere in the analog chain. ) that tolerate some " guesswork " in order to achve desirable targets.

There is not much research on the subject and not because there are not good audio item designers ( there are ) but mainly because there are too many " conformist and non know-how " customers: why a designer has to worry on a " perfect " design when no one is asking for? when almost no one cares about?

Almost all the analog audio item designs are more a commercial subject ( $$$$, in some ways it has to be, between other things. ) that a top quality performance to bring a top satisfaction to the customer, even the very high price items.

Where are the customers? where are we? how can the analog audio market really grow-up if we are " satisfied " with what we have? we are satisfied with the same/similar audio item designs of " 50-100 " years ago ( many times lesser designs. ), where we leave the " emotion " to explore to discover to think in a " new " way?: almost no one cares about and IMHO that's why: ++++ " I have yet to see a turntable design done right. " +++++ ( or almost any other audio item. ) we are " down " here " ( in a deep hole ) and not because there are not good " professional " designers ( there are: several. ) or people with the enough knoledge to do it.

This is not the first time that I point out these subjects and if we continue to pay for " mediocrity " that's will be exactly what we will have: " mediocrity ", IMHO I think that we need a customer " revolution ", we need to shake all those talent people out there for they give us what today we deserve, we are " the one " to make things change for the better we need to be active part of the changes.

Regards and enjoy the music.
Raul.
I'd be interested in the discussions and ideas about turntable design and the 'pure physics' involved, yet at the same time, I'd imagine the 'real' turntable designers, those who have done the physics and actually produced a saleable commodity, laughing at us 'amateurs' wasting our time and efforts without the prospects of reaching any meaningful conclusions or resolutions?
Do we really believe that Mark Doehmann of Continuum Audio has invested 10 years of his life together with a team of 7 experts in various fields of mechanical, aeronautical and advanced systems engineering without understanding the physics involved and then testing the prototypes and manufacturing a finished workable product?
Or the Suchy family who have years of experience in turntable, arm and cartridge design?
Not to mention Harry Weissfeld, Lloyd Walker, Andy Payor, A.J. Conti, Roy Gandy and even Ivor Tiefenbrun?
And yet, for every turntable designer, there is a different solution or variation?
It is so easy for us to 'surmise' and point to the 'weaknesses' of various design philosophies but as the saying saying goes......"those that can, do and those that can't......?
Surely Dertonarm, if pure physics made it all 'black and white' and "I have yet to see a turntable design done right."?.......why have you not yet......done it!?
Dear Raul - I do agree with you 100%. We - the customers - are indeed responsible for the products we get. Unfortunately we are a very small group inside the whole market for audio playback. As our buying power is way too small for the (global players..) industry to focus on, we do only get attention from companies which are small enough to be able (and are forced to...) to focus on a small niche of the market: - us, the audiophiles willing to spend fairly large amount of money to get satisfaction for their endless task for perfection and beauty in musical reproduction. And another "yes" - we will get mediocrity a plenty as long as we continue to buy it.
Only market behaviour will change the quality of the product. Nowhere as true as here in "our" market.
Dear Halcro,******......."Surely Dertonarm, if pure physics made it all 'black and white' and "I have yet to see a turntable design done right."?.......why have you not yet......done it!? "******

I did.
Almost 20 years back. Together with 2 collegues I have designed and built (and they have been sold) 15 units and it did costs me alone approx. 230 000 US$ back then.
However - it was a turntable you simply could NOT sell through any High-End store due to size, weight and technical periphery needed.
The infamous WAF was way below zero. The technical features - brief summarize: a 100 lbs (very complex design internally) compund platter with a still unique approach of clamping the LP - suspended on radial AND lateral air bearing with 4 bar pressure. Whole 400 lbs turntable suspended by active air springs with 0.5 Hz resonance frequency. The motor drive - in the last incarnation without any force vectors on the bearing!! - was the big capstan from the professional Studer tape-machines. This design was backed up in the research and the tests by a division of a technical university.
Believe me - I have done it the hard way. For several years. There are good reason why my former remarks were the way they are.

As for stylus drag: - stylus drag is mainly the result of the downforce on the groove (vertical vector on the groove wall). That downforce is a result of the size of the polished area of the stylus and the VTF. Frequency modulation does vary that force only ever so lighhtly. So there is a varaition in that force, but only very faintly. AS the majority of the force is constant, it does add to the "friction" - however, it does not require correction during operation (which is impossible anyway ..... as you would create an error-correction-loop resulting in anything but certainly not constant speed).

Dear Halcro, I am familiar with all the above mentioned turntables. All those people need to SELL their turntables. Thier turntables need to fit into the living rooms of fairly well doing customers (at least if bought new in the store...) with some taste and expectations in design and a better half which sometimes does have a vote too. Furthermore their is an importer (sometimes) and a dealer (soemtimes) who need their part of the financial cake too.
In the very first all these turntables were designed and built for 2 purposes:

** unique selling proposition (by design or unique technical feature) to support the 2nd purpose:
** to make money....

A turntable "done right" will be huge, very expensive, extremely heavy and will feature some technical periphery aside the turntable itself. Imagine the working bench of a large electron microscope....... then you get an idea.