Tables That Feature Bearing Friction

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.

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............

Dear Halcro, thank you very much.
To speak in the words of an era in architecture we both do favour: .....form follows function..... ;-))

Hi Dan_ed, I do not use the Platine Verdier. Furthermore I do not see that I have refered in any way to the sound of the Platine Verdier.
Did I ?
My comment was about a construction feature of the Platine Verdier which was used in this turntable indeed for the very first time in this particular context.
BTW - I have listened to about every commercial turntable released on the market the past 32 years (and a few non-commercial TTs too...).
However - you would never read any comment from me regarding sonics about any current market product ever.

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.

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.

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.

Dear Teres, yes, I could grant your last post with some technical counterpoints and facts, but the only result will be argument.

But I can not resist.

****Thankfully, turntable design is not pure physics. A good design also includes compromises, tastes, experimentation and even some guesswork. Otherwise turntables would all look and sound the same. Really boring...*****

Well - turntable design is pure physics.
A turntable is a rotating machine.
That rtation has to be constant and its dynamic forces have to be that large that the extraction of the modulation by the tonearm/cartridge system have no side-effect on the constant rotation.
Furthermore the whole machine has to be suspended from building resonance.
Period.
Would you argue about a wheel and its function??

Stylus drag is a very small sliding force in constant motion and is - coupled with any serious platter (of course not if the LP lays just on the platter and is not firmly clamped down) - really neglectable. Its a force smaller by several magnitudes compared to the energy the stylus puts into the platter while modulating the groove information. A force smaller by several magnitudes compared to any motor generated vibration.

It is not a magic stone nor does it inhibit mystery unknown physical energy which puts it outside the Einstein Continuum ( however - many audiophile seem to believe just this and are supported by commercial audio advertising....).
The fact that "taste, compromises, experimentation and even some guesswork" is included in the design of turntables is the reason why almost all turntables do indeed "sound" different and most do sound pretty boring.
If the NASA had handled the Apollo - Mission that way, man would have never set his foot on the moon.

I have yet to see a turntable design done right.
I have yet to see a turntable with written standard specifications to start with.
So far we have a few good amateurs, but no professional anywhere.

I agree with you Dan_ed. However - the eddy current brake approach as shown by J.C.Verdier isn't all that costly. All you need are 2 old 15" woofer dirivers magnets which never suffered from shock or extreme low temperature. Thats about all you need to get those 3 features mentioned above all in one.

BTW - idler drive was introduced by and for the broadcast service turntables first. Kind of heir from the days of the grammophone. For good reason. It was of paramount importance that the platter had full 33 1/3 rpm after less than 1/2 turn. You need it for broadcast. For timing the tune played next. When direct drive had grown to full mature (by mid 1970ies the latest) the idler drive TT all vanished from broadcast stations.

Idler drive needs extreme care in execution to supply good results for turntable application. It however always gives some problems as the idler wheel itself is a source of direct noise transmission to the platter.

The idler drive is the direct counter-approach to the belt drive - one favours direct coupling between motor and platter to have very direct and immediate control over speed. The other favours as little influence and as little coupling between motor and platter as possible to minimize any possible vibration and speed shift in the motor being transmitted to the platter.

If the time frame till stable speed is actually reach is of little to no importance, - a very heavy platter coupled by string (= little grip) and driven by a very good motor will give the most stable speed for a turntable. Huge inertia combined with "slip coupling" or a kind of "cumulative coumpond motor drive" (read: very good motor coupled via string to a platter with little grip). If correctly done, it will take fairly long to get to stable speed, but once there, the speed will be extremely constant and little changes in the motor have no effect on the speed of the platter due to the - wanted" slip/low grip of the string.

Of course, this is one of many approaches in today and yesterdays turntable design. It is however the technical engineers approach if absolute stable speed to the prime goal. And if the time taken to reach this stable speed is neglectable.
The whole scenery is worth musing about. However this approach does ask for fairly expensive components (= high quality = expensive motor and very large mass in platter and extremely precise manufacturing and tooling) and huge weight in platter. Nothing that can come cheap.

Dear Raul, right now I am in the process of building the successor of the turntable Syntax has pictured. This project will be finished in autumn this year. I will include some thoughts and technical features I either could not include back in the early 90ies - or which came to mind in the last years.

I did not post any pictures of my system, as it would not help people to get an idea. Aside from tonearm and cartridge none of the other parts of my system are commercial products. However - I will briefly describe the system.
The preamplifier is all tube. Split passive RIAA. First 2 stages are full differential stages (1st time constant of the RIAA is equalised here). Between 2nd and 3rd stage the other 2 time constants are eq'ed. The 3rd stage is a pure plate follower. All triode. The line stage is full passive with transformer attenuator made by friends in Japan. Output impedance is pretty constant 120 Ohms. It drives several meters cables and 3 different pairs of amplifiers in parallel (and live athmosphere, rich colours and live-dynamics are my prime focus in playback audio). The preamplifier is full hand wired with all silver. All tube sockets are mounted on individual PTFE platforms in open frame architecture. All resistors are Shinko Tantal. All capacitors are silver foil in oil. The whole open frame arcghitecure of the Phono circuit is itself suspended inside the 2 cabinet preamplifier by special soft rubber anti-vibration poles. The powersupply is full dual channel with 4 rectifiers (double single wave) and all PP power capacitors with dual bifilar choke LCL filtering. All selector switches are massive silver TKD. Total 6 phono inputs with various transformers to accommodate and match any given source impedance and inductance by any moving coil and MI or MM.
The whole system is tri-amplification. E
ach woofer is sealed cabinet, 18 to 80 Hz with 500 Watt amplifier with active DSP. The woofer driver is a 18" unit with an BxL of 32 and maximum excursion of total 28 mm in sealed 70 litres. Mid bass and mid-highs is a 2 way system with 8" field coil paper driver with huge choke power supply and 80 000 µ filtering. 12 V supply. The tweeter is a 28 lbs unit which goes from 800 to 45 000 Hz. A ribbon / planar hybrid with 100 dB efficiency (past crossover). These two are mounted in an inverse ultraflex cabinet with a combination of 1st order electrical x-over (1 coil in low-mid - 1 capacitor in mid-high) in conjunction with approbiate mechanical filtering in low-pass (pre-chamber) and high-pass (super short tactrix). The cabinet itself has a special adjusted build-in mechnical high-pass with -3dB at 80Hz. Thus giving a pretty smooth melting between the active 18" woofer and the 8" mid-low driver. The whole system has measured 99.5 dB efficiency. Max. SPL 128 dB. Phase never worse than 8°. Pretty flat response whole band.
The amplifier for the tweeter is a special 8 Watt 1 single pair bipolar concept designed by STAX/Japan in 1980 but never commericalised. It has a double 12V - 2 000 000 µF power supply, soon to be put on complete battery supply. It is capable to deliver 5000 A for short moments. The amplifier for the mid-low (80 - 800 Hz is a single ended MOSFet design with OPT. 11 Watt. The shortest signal path of any amplifier. Very similar to the Western Electric type 25 amplifier of the 1920ies, but build with a special MOsFet and matching huge Output-transformer. No input stage, no driver stage.
Tonearm is - no surprise - FR-66s and cartridge is a very special FR-7f modified. Cables are Audioquest SKY w/144v DBS all in NF and flat ribbon pure silver for the mid-high and mid-low.
But honestly - I do not think that this description is of any help.
It rather illustrates the point that I am not too impressed with the offerings of the industry but like to go my own ways.

Dear Teres,
stylus drag is only an issue if the record is not firmly clamped down to the platter.
If the record is not firmly clamped down, we do not need to talk about correct application or technical issues anyway. This is basic parameter. If securely clamped down it becomes part of the moving system and its mass - hence: heavy platter with high inertia.
As I said before - this is only one approach and certainly not the only one in igh-end audio, but it is the approach of physic and technical engineering.

A heavy platter will have no variation once it is on speed.
Any possible loss in speed is avoided before it occurs - by correct allpied coupling with string (= very low grip but enough to avoid loss of constant speed). Thus the error does not occur but the only task for motor and string is to hold the speed - nothinh else.
Stylus drag do only have an effort when the record itself "slips" on the platter surface (and believe me - I do use a cartridge which really can "drag". But of course it is only going on a record which is firmly - really firmly - pressed down on the platter).
Sometimes it really helps illustrating forces in motion with vector diagrams on a sheet of papaer. Visulising what really is going on does set some points clear really fast.
This is physics - thus it can fairly easy be determined when you allow the facts to spread.
Trying to correct any variation in speed as fast as possible ............
The result is constant back and forth in speed.
In other words - you implement unstability by doing so.
Every technical engineer into dynamics or constant torque will tell you that this is futile.
Turntable is pure physics - not taste, not opinion.
Too often in High-end audio people get the impression that physics laws have been invented during the development of audio components.
Not so.
Extremely few audio components - mechanical ones like tonearms, cartridges and turntables - do really take correct applied physics into account.
Otherwise we would have much more better components around.

Hey Dan_ed, really ? I expected my post would provoke something like this. After all nobody likes big mouth with no proof behind...........
Any other Agoner interested in this ?
Specs including given reasons - or plain specs ?
Including material selection?
If some interest for this I will gladly unfold a brief but detailed enough "roadmap".
Let me know your mind.
On the other hand this is far going beyond the original thread about the bearing friction.
Maybe we should start a new thread ??

Dear Kirkus, Lewm, (Teres ??) and Dan_ed, if we all join forces in this discussion I am positive that it will become a really worthwhile discurse.
Of course - stylus drag is rather a very variable force and can not really be called a "constant".
So - how do we proceed?? Do we carry on in this thread or is one of you starting another focussing on the turntable design in general, maybe with stylus drag and its influence on stability as a sidematter? Any suggestions? I am happy to participate in a real good discussion when we focus on technical aspects.

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.

As for the Micro Seiki original belt / strings. The Micro Seiki RX-5000 came first with a fairly strong and wide rubber belt of very high quality first. However they did recommend too - right from the start - using an aramide string ( made out of 134 individual fibres ) to get the very best results possible.
Because of less vibration transmission towards platter - and: slip coupling....... resulting in much better constant speed.......

Dear Kirkus, indeed. Suspension of ANY turntable from vibration (if possible from air vibration = sound pressure too........ but that is another story...) is elementary. It is not a question of idea, philosophy or sound preference. It is vital to isolate the turntable from any seismic vibration. That implies that the suspension should go as low as 0.5 Hz to ensure isolation from building resonance. ANY vibration will falsify the groove modulation and alter its amplitude.

Again - we have the picture of the active or passive (if possible... air) isolated work bench for electron microscope. The working conditions for that electron-microscope are almost identical to the ideal working conditions of a turntable (at least of a turntable trying to go for anything near maximal possible performance). Both dealing in similar dimensions too.
Every owner of a decent turntable - already with built in spring suspension or not - can easily check this for himself. But a Vibraplane or a Minus-K or similar benchtop platform underneath any given turntable of at least some merit. You will notice the difference right away (no - I do not hold any shares from either company mentioned....). These platforms were designed for small elctron microscopes and vibration sensitive measurement equipment. No high-end nonsense, but straight industrial devices.
Well worth a try before you spend the next grand on a 3 feet NF-cable.....

There is one other vital aspect I want to point out: energy transfer between two masses. One mass in active movement - the other serving as the (static) floor. Picture a billiard table and the ball in motion. Ever wondered why the billiard ball does roll longer on certain tables? Because there is a direct relation between the mass (= thickness of stone platter underneath the green wool) and the energy transmission between the ball and the table. The ball stops earlier on the cheap (= rather thin marble stone platter) and lighter table. Energy transfer. More of the energy of the ball rotation is transfered into the mass of the table. If the differences between the 2 masses is increased, the ( unwnated !!) energy transmission gets less and less. The ball has a longer run - it can use more of the energy given by the qeue's poke for its motion.
There is a very similar relation between the stylus and the platter.

Dear Kirkus, there was no way to put that design into a commercial product. Too big (the Caliburn, Goldmund Reference, Micro 8000, Raven etc. were all dwarfs in size), too heavy, too much periphery, your wife would have shoot you and divorce (not sure which first...) upon the sight in teh living room.
And no way for trickling down in more convenient size and financial frame.
Anyway - I will do it once more this summer and autumn and will include a few technical devices which I could not integrate 20 years back. I will post the pictures and specs of the turntable in late autumn here on audiogon.
For all to share.

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 ........

Ghosts of the past.........that particular unit is from 1993.
The base plates are corian on dural with polyurethane layer.
80% of the technical periphery is inside the integrated "stands" of turntable and motor unit (including active air suspension, surge tanks, automatic leveling.
Dimensions were 4 feet wide x 2.2 feet deep and 4 feet high. Total weight approx. 580 lbs.
Every wife's nightmare.
The motor unit does feature selective air supply for up to 3 airborne tangential tonearms (adjustable pressure and amount of air - these were the days of Air Tangent and ET 2 back then.....), adustable air supply for active suspension and radial / lateral air-bearing. All speeds 33, 45 and 78 are precisely tuneable.
And this was 1993........

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 Raul, yes - a different room is the one and only way to isolate any turntable effective from SPL radiated by the speakers. No doubt. However - this has nothing to do with the turntable design itself. It is a matter of the enviroment/position. Put the turntable in the next room and drill a hole through the wall to allow exit of the tonearm cable or the NF-cable(s) from preamplifier to poweramplifier(s) - è voila!
But - a turntable can be designed to "near perfection".
"Everything possible to be believed is an image of truth " (William Blake , end of 18th century).
Its a matter of consequence, effort and energy put into the task.
However - a "near perfect" turntable can NEVER be a commercial design.
A space shuttle will never be a commercial product either (not as comparism here, but to clarify the point...).
Neither can the "near perfect speaker" and its cousins the "near perfect preamplifier, poweramplifier (always in close relation to the crossover and efficiency of the speaker) etc "(well, the pivot tonearm and the cartridge - that could work in the narrow frame of market-conformity). Any other commercial audio product will be - and was so far - always a (often more and rarely less) dreadful bundle of compromises (god - I hate that word since childhood!!).

To come anywhere close to the "near perfect" in audio components means in plain simply words:
- leave commerical audio products and the idea to bring that "near perfect" designed audio component to a "market" behind.
It will not work.
You have to do compromises to bring ANY product on a "market".
There is no free lunch in high-end audio neither.
Well - theres an old saying: nature knows no compromise.
Compromise may be indispensable to keep our past zenith society working as long as possible.
If we accept all too easy compromise in the development of audio components we will always get what we deserve and have gotten so far:

.....mediocrity......

Dear Lewm, we can not achieve perfection - we can only try. The long string is no compromise at all. Yes, the string has no stretch at all (a special kevlar derivate). The point is not control of the platter rotation. The point was to prevent the platter from loosing any speed. Control is futile. The platter must be stablized by inertia. Control and correction in speed will always result in a constant error-correction-loop. Thus creating instability and a constant change in speed. I think this is a clear fact - everybody into technical affairs and physics will agree in this after giving it enough thought. The inertia of the rotation platter is so stable - you can't even dream getting that stability with any direct controlled (= speed control both positive AND negative by the motor via direct coupling ) platter (dd, idler or belt drive).
I certainly do not want to start any philosophical disscusion here, I just tried to illustrate the point that all too often we go for a compromise WAY TOO EARLY and WAY TOO EASY.
Compromise in our culture is a positive term - because it helps to accept unpleasant facts and things the way they are.
For me compromise is another word for surrender.
I think we should not accept surrender (=compromise) too early - without trying our very best.

Dear Kirkus, yes, I have put some money in that project back then, but I got paid back and in the end I did not loose any money on that project.
As I usually do like to link philosophy with my audio discurses, I must however admit - not today . I am not in the mood - I am afraid. Most likely it will brighten up again tomorrow... ;-).
So rather plain and straight speak now.
So far my odessey in audio has been - on the large scale - cost neutral. I rather wanted to illustrate my point that all too often we do give in too easy. All the money I did put in that project in the early 90ies did not come easy. As I certainly always had to work for my money I wasn't too tempted to throw it away. I did put lots of work into that project - much more than money.
I wasn't on a field campain just to bring as many troops as possible on the battlefield as to crush the enemy by simply overwhelming him by sheer number and brute force.
From the plain dimensions this may look as just another gigantic egomatic turntable where weight and money were the driving forces and the brain was replaced by the big wallet.
Certainly not so.
Cost was an object indeed.
Sadly enough - I do not have money to burn.
Not back then - not now.
Being self-employed means you work everyday and on your own (your own risk too....).
I am certainly much more on a budget regarding my audio passion compared to several other Audiogoners.
Thats why I designed my own turntable, amplifiers and speakers.
Because I am on a budget AND because I did not find what I was looking for.
There was much more research put into that project than my mere words and the picture can tell.
It may however give some reason why I am not too impressed by the "state of the art" turntables of today.
Maybe I just want to say:
I know what I am talking about ............ nothing else.

BTW Raul, one sample of the turntable was in Mexico City from 1993 to 1998. The owner was (and still is...) the former director of BMW Mexico. I sat up the table in your impressive city.

P.S.: agreed on the ET2 - it was just mentioned to clarify the point why the TT had several individual adjustable air supplies for the many different designs in airborne tonearms around in the early 90ies - all having different needs.

In fact Micro Seiki 's engineers were the very first to realisze the potential (in turntable design...) of high inertia coupled with thread drive resulting in superior extremely constant speed. Low grip, slip coupling and let the huge mass in rotation do stabilize itself.
I mean - it works pretty well with our planet (and a few trillion other planets too.... yes, I know - there is no stylus drag on terra..... and it is a rotation in open space = vacuum) - why shouldn't it work with our turntables??
But again - you can not do it cheap.......... huge mass platter ( = expensive), very strong yet high quality bearing to handle huge mass platter (= expensive.....), high quality motor (good capstan - for instance...) (= fairly expensive again).

Not to speak about suspending the combined high mass with super low frequency from building resonance......

Dear Kirkus, I know that these were not your motivations - I just wanted to set some points clear as the turntable sure looks like a "mammoth" in the picture and thus the above mentioned suspect might easily arise. But - thank you.

As for the string - just briefly and preliminary, as I have to leave the computer soon:

The basic idea / principle is to have a homogenous mass put into constant rotation and then let the inertia do the job. The string in its kind of "slip-coupling" (which is kind of tricky to set-up and needs a calbrated spring gauge to ensure the perfect "non-grip") does have only one job (after bringing the platter on constant speed once):

- prevent the platter from getting slower.

All I can say - and this time I just plain ask you to take my words for granted - is: it works extremely well. We made long period measurements in MTU in 1992 and the derivation from 33 1/3 was (short-period as well as long-period derivation measurements) as close to zero as possible (measurements were taken with laser beam and calibrated circular stroboscope foil).
And - yes, the measurements were made while stylus was in the groove.
This is a huge inertia (the platter is 326 mm in total diameter - 108 lbs) in motion.
Once in motion on the desired speed, there are no derivations. The air resistance, the bearing friction (...the stylus drag..) these are all constants and thus the rotation stays constant.
It however takes about 2:35 minutes to reach constant speed........
The string just have to be dyneema or kevlar derivate and the coupling has to be precise.
But it works marvelous and watching it work, you get a certain "feel" of "completeness" and "natural move".
Audio phrases......

Time to get off.
Good night for now.

I went through Mark Kelly's extensive teachings. Good research and explanations, but he is not focussing upon the center point.

Some people will hate me for this, but I want to postulate a short and clear statement ( and I ask everybody to give it some deep thought before telling me I am wrong....) regarding ANY principle in turntable drive (idler, dd or belt):

The motor of a turntable has ONLY 2 jobs to handle.
1.) bringing the platter on speed
2.) preventing the platter to slow down once it has reached that constant speed

There is nothing else the motor / drive has to do.
Physics and logic will result in a huge inertia ( = huge mass of platter) providing an extremely constant speed by its own rotation. It will too result in a coupling which does allow some slip at BOTH ends of the drive system - platter AND motor (such that little variations in speed generated by the motor itself will NOT make it onto the coupling device (string, belt - whatever). A say 35 -50 lbs platter on 33 1/3 rpm rotation has a VERY constant speed (much better in its constant speed stability than almost all motors in use in todays high-end turntables).

It is not about control between motor and platter.
The platter will not get any "faster" once it has reached its determined speed.
It gets slower due to air resistance, stylus drag etc. But those are constants in real world application.
So - all the motor and its coupling device have to do is preventing the platter from getting slower.

This automatically does lead us to a definite slip coupling and a huge inertia.
The way to get ultra constant speed and practically zero derivation in as much inertia as possible (in real world application).

Give it a deep though before jumping to the keyboard telling me a stupid, narrow-minded fundamentalist.

Its all about masses in motion.
Again - its all physics.

The trade-off is a long time to arrive at stabilized (2-4 minutes) speed.

Dear Teres, dear Raul, I guess we all agree in most aspects regarding the main topics / issues of designing a turntable.

I just have a very different threshold for "compromise". However I would like to answer Teres's 4 points first and in order.
I will speak very frankly here, as I just do not want to waste time and words.

1) Well - the physical phenomenons regarding the turntable CAN and ARE fully understood. Unfortunately and apparently not by the majority of turntable designers.
This is NOT all that difficult.
Unfortunately there are a lot of ill-founded theories and nice opinions around - right, but there are also the facts.
It is a fairly simple model consisting of two parts linked in one moving mass.
We have a rotating mass (the platter), that has to been kept on constant speed. The speed vector is provided by an external source (the motor ....whatever motor) the imperfections of that source (vibrations, unconstant speed) shall not be transmitted to the moving mass. This is one part of the whole system.
The second part is the act of extracting the musical information from the record groove. This act is a long line of different (both in amplitude and frequency) mechanical impulses transmitted into the record and into the rotating platter (the moving mass in motion = part one of the whole system). These mechanical impulses (which are a direct by-product of the stylus extracting the information from the modulated groove) depend on the VTF and the compliance of the cantilever (a FR-7 with low compliance and 2.6 gr VTF will transmit much more energy into the vinyl compared to a Shure V15 mk5 or similar (to name two extremes) while running through the groove and de-modulating the engraved information).
However the moving mass - the rotating platter - is therefor "threadened" by mechnaical vibrations from 2 different sources and (maybe - if anything like direct coupled) variation in speed from its external source of speed.
How to solve problem no. 1 (source of speed = motor) was discussed by me the last 2 days and is so far the only suitable solution if you want to use a motor (or multiple which is NOT a good idea...) at all.
One major point needs to be mentioned here which was so far not brought up: - of course the bearing of ANY turntable trying to bring out anything near the best possible must be TOTALLY free of any force in horizontal direction.
In other words - free of any force vector.
In plain words - there MUST be a counterpoint creating the very same force as the belt, thread, string etc. from the exact opposite direction and thus elimination that force to total zero.
Before this is not done, we do not need to talk at all about variations in speed, stylus drag, etc.
A direct drive doesn't have that problem of course.

Due to the fact that the act of playing a record does indeed brings the record into vibrations we need a heavy platter ( thats why heavy platters - if of any quality - ALWAYS do provide more substantial sonic information in both frequency extremes).
This platter must be - seen as a body - as insensible to vibration as possible. Consequently we are leaving the shape of a flat disc and platter and strive (if possible ....) towards a "round" cubus or (theoretical ideal) ball. To further increase the insensibility to vibrations other than shape is creating a compound "platter" made of materials of very different resonance behaviour
These are basic fundamental physics and nothing special.
The higher the rotating mass, less and less energy will be transmitted ino the platter.
If teh record is clamped firmly to the platter we (in an ideal situation...for which we can strive...) see the records mass being part of the platters mass. Thus less and less information will be dulled and smeared by a vibrating record (as Kirkus will agree, this is very similar model to a woofer working in a rather light and resonant wooden cabinet compared to mounting it in a stone wall - we both know that the dynamic, detail and clarity in impulse is dramatically different in these two mountings. It should be clear why.) and the pureness of information is greatly enhenced.

The point of suspension from outside mechanical resonance (building resonance) was discussed earlier and the solution is simple and can be obtained as a lug-and-play solution from suppliers already mentioned.

2) A turntable does not provide good sound.
A turntable has to had no sound at all. As above stated - all sound and music (should...) come from the LP itself. All the turntable can do is not ruin it. A good turntable is a dead turntable (as regarding sensibility to vibration and inner resonance). There is no such thing as a "good sounding turntable" or a turntable with "emotion (aside from its outlooks...)" or with "rythmic drive".
I mean these turntables may sound "good" and give the impressions of the above mentioned sonic features.
But they only allow these positive features to unfold.
They are in the record.
The other TT's just destroy and dull them in one way or another to more or less extend.

3) Nowhere is the relation between "good sound" and pure physic as easy and as direct as in the turntable.
I will always agree that there are tastes and many different ways to reach (Rome...??) excellent sonic results in speaker design, amplifiers and cartridges (I am less generous with tonearms.....) - and yes, we do indeed NEED distortion in amplifiers (2nd harmonic order..... only.).
No so in turntables.
Its all physics here - no mystery, no genius, no secrect, no ideology.

And again - if we are talking designing a turntable as a "product" for a "market" with "value for money".
Well, - than this discussion is futile from the very beginning.
A turntable very clos eto perfection CAN and WILL be build.
But it will NEVER qualify for a commercial product.
We do not need to compromise because the turntable is so difficult to build.
We need to compromise to make it to a "product".
Because here some people must have their financial share.
The product is the compromise - the compromise is not nessecary per se.

4) A turntable does not sound.
It allows information to be extracted without alternation - or it fails in some parts or many.
Allowing some parts and smearing and dulling others results in a "sonic signature".
All other parts of the audio chain do indeed have sonic individualities - cartridges, cables, amplifiers, speakers. All these are either elctrical devices or transmitters between the mechanical and electrical world (cartridge and speakers).
Not so for tonearms and turntables.
They are purely mechanical devices.
And we can make them closer to perfection as any other part of the audio chain.
We just have to be consequent and dare.
As for the perfect turntable - in the words of your new president: .... yes we can.....

I totally agree with you that the high mass platter does make the motor / belt / thread less critical.
But if you combine a super high quality motor with excellent power-supply with a really heavy platter and superb bearing and drive counterpoint - then we getting close in bring part one of the system close to perfection.
This is very significant regarding a vibration and force free system - and thus - after all, significant for musicality.

Dear Restock, a superb post - thank you very much! I would like to mention however that I do not see me in some kind of opposition regarding Teres, Raul or any other of the well-respected contributors to this thread.
I just wanted to clarify the point that this particular part of the audio chain is - besides the tonearm... - the most simple to handle. Here we do only have to work with mechanics. The other components are either electrical or machanic-electrical transducers (much more complex ). Taste, personal preferences and opinion, room interaction and matching impedances and many more do have enough room in the development ofspeakers, cartridges and amplifiers. and they are NEEDED there.
But not in TT design.
Yes, -in the end everything in music in subjective.
But the very best turntable possible will have absolutely no sound signature of itself. It will just allow the maximum in clear detailed information to be extracted from ANY given cartridge/tonearm combination.
The turntable is nothing more than the enviroment, the basic floor on which the analog-playback starts.

But if we relay on hearing/listening in turntable conception and design, we automatically imply that the turntable is the weakest part already and per se in the particular audio-system used to determine its quality.

We all see the problem: to judge the performance of a turntable design by sonic performance, we would need an audio-system were all the other parts are "better" than the TT under question.
But most likely we will design a turntable which "sonic signature" will mask certain flaws of the audio chain used to develop the TT.
It will be designed to compensate flaws of the evaluation system used to develop it.
This dilemma is omnipresent in audio of course. However in the turntable we have for once the opportunity to design on pure physical, mechanical parameters and facts.
I do see a clear and straight road here.
It may be long road and the journey may take a lot of effort in many ways.
But the goal is that mountain clearly visible in the distance - not the next inn or diner which will lure us with comfort (=compromise) by the first signs of effort or weariness.
Once entering the door of that inn and sit down at the table you will not carry on on that journey. The day is done and teh job as well. You went awhile and has reached new ground. Its o.k.
Thats what happens all too often.
We should be strong enough to walk through the night.
We should not discard the opportunity to reach the mountains that easy.
As is so pathetic written on the memorial for the american pioneers (hope I remember is right... in brackets are my synonyms....):

"the cowards didn't start (CD-player from Radioshack....), the weak died on the way (settle happily with current "state of the art products".....) only the strongest reached the mountains - they were the pioneers (.....and probably died exhausted, wounded and torn by life - but o.k., if they did what they wanted and reached what they dreamed of)".

Well, sounds like a pathetic political speech for fortify indurance in the sight of worldwide financial crisis doesn't it ??

Did I mention this is about turntable design....?

Dear Mrjstark, dear Teres, if there is more then theory, then we are either in mysticque or religious grounds.
Different belts having different (negative and positive) effects on the bearing an dteh rotating mass system and on the transmission of vibrations is certainly no mystery nor unexplained by sience.

Dear Lewm, a no force belt/thread/string driven bearing is done this way: picture the motor left of the platter. On the right side - same distance as the motor to the bearing - is a 2nd spindle (or easier: motor without active force) which mirrors the position of the drive motor. Here the belt/thread/string finds a 2nd pulley equal to the one on the motor. The spindle of this "counter device" should be same as teh motor sindle and all its moving parts shall be equal dimension and material.
Correctly done, there is now no resulting force anymore on the bearing in horizontal / lateral plane/dimension. The force of driving has 2 equal vectors now which do give which do zero each other regarding their effect on the bearing as they do go in opposite directions.

Dear Kirkus, the "controlled slippage" is tricky to set-up, but if used with the "right" (= close to zero elasticity) thread it is very durable and does not request to be re-adjusted.

The drive-system is - as always - a matter of quality in the selected parts. I still do favour using any of the big Studer 800 capstan motors as drive motor for a "good" turntable. These capstans are expensive -yes. They require some pretty expensive periphery too - yes. But they are a totally different league.
These capstans are at work since the 1960ies in almost all great recording studios and a majority of all music recorded between the late 1960ies and early 1980ies (and beyond...) were recorded with these capstans being a direct and very paramount part of the big tape recorders.
Use one of these and give it the regulator circuit is needs and 98% of all problems with other motors and drives are vanished. Motor-born vibrations are minimized too.
And yes - it will cost you about $2000 alone in parts.
Quality NEVER comes cheap.

As for the clamping platter record interface. I do have the solution for that problem at hand. It however is rather expensive and labour intensive again. I do not think it makes sense to unfold it here.
The discussion about again too expensive and not suitable for a commercial product and crompromise etc. will just go on and on.

In general we shoul decide, whether the main subject is how to design a turntable as a commercial product, or how to design a turntable which tries to reach the limits of playback possibilities.

I must admit that it is rather depressing for me to read in these posts so frequently that "this gets too expensive"....."have to made trade-offs".........."well-choosen compromise"........ "bring to market"........"commercial product".

This all sounds like the usual political paraphrases.

As was mentioned before - if we do not demand and strive for the best possible (an audio industry will tell us it is the "best possible" anyway every 4-6 months...) - we will only get what we have got so far:

......mediocrity.........

Dear Mrjstark, if you ever should try different belt materials on a force free lateral (horizontal) bearing, you will observe that the noteable differences in sound will be much less compared with the differences noted in the "standard" (=one motor - no counter spindle) set-up.

Why do we hear so huge difference (I will certainly not deny the fact that there are audible differences with various belt / thread materials and other tweaks in turntable design (mats, clamps, isolator feets, spikes, platforms etc.)) even in state of the art turntables ??

Because these turntables are NOT finished "products" (seen in the sense of a market or as a non-commercial design).
Most likely the designers were under time-pressure and/or seeing the end of the budget and thus need to bring the TT "on the market now".
A "finished" turntable (or any other really "finished" product....) will either show no positive differences with various tweaks or they aren't possible at all due to a design which takes all aspects into count and leave no room for our "add-on", "upgrade" or "tweak"-mentality.

You can't tweak a turntable with force-free bearing running with an aramide or dyneema thread. There is no better material possible so far.
You can't tweak a Minus-K 0.5 Hz suspension by putting spikes or cones underneath. It is already suspended in the best possible way.

We do hear so many differences with so little changes in so small parts because the turntable is so weak.
Because there is so much room for further improvement.
Because we stop too soon.
Because we are satisfied with so little.

Dear Dan_Ed, agreed on the large scale.
And yes, - there will always be "some" (I hardly can write the word...) "compromise".
However NOT SO FAST.
I do get the impression that most designers are seeking for the nearest possible compromise.
That the real goal for most is: finding the best (read: cheapest and nearest....) compromise as fast as possible.
I have no problem with a compromise when there is NO OTHER CHOICE possible. That is early enough.
And frankly - that point will never be reached in turntable design.
We should get real, we are talking about turntables - not about space shuttles, Formula 1 racing cars, atomic submarines or the hubble telescope.
A turntable - a simple mechanical machine....... sorry, I can not see any need for compromise here. And we do not need back-up by the Pentagon or Northorp Aviation to be able to design and build a near perfect turntable.

Dear Dan-Ed, yes, are you happy we arrived in the "real world" (was Neo happy when Morpheus showed it to him...?).
Of course, compromises are there. WHERE they can not be avoided I agree to them. However - I can't stress this often enough: the one basic fault is to make the compromise the goal. And that is what is happening all around and what gives us what we deserve: .... mediocrity or worse.

My point is that the compromise is o.k. when there is no close to ideal (= near perfect ) solution possible.
However - once again and for all - it is NOT nessecary in turntable design.
To accept "compromises" here in the early stadiums we see them in almost all turntables around - those are not compromises.
That is poor, unfinished design.

Named "compromise" just because the designers could not do any better or did not want to go any further (for whatever reason...money , time, market call).

"Unevitable compromises" in a machine as simple and small as a high-end turntable............... really, give me a break - we are in the 21st century not in the dark ages of mechanics following the decline of the roman empire !!!
Its poor performance - not unevitable compromise.
Period.

Dear Dan_Ed, I can't offer the eloquence displayed in your opening sentence of the last post, however I will once and for last try to clarify my point:

Compromises where they are inevitable.

As for the questions asked:
- no, string tension was not that critical - it just prolonged the time frame to full speed.
- yes, it was no problem to find repeatably the right tension. I had a calibrated spring gauge and a laser to determine it.
- DC and / or AC - as I wished. The controller was the control board from the Studer fortified with a custom build amplifier to create the signal.
There were compromises in my early design too. Some I did only detect years later.
None that were detected by others. None that others detected in their designs ever.
Thats why I am doing it again this summer and autumn.
But even if I go on and on with the details it will not cure the problem.
Me insiting on the "no need" for compromise in turntable design seems to be a kind of sacrilege to some.

The human experience shows us that it took almost 8 Millenias of civilisation till democracy took over on a larger scale.
Does this proof anything??
One century of turntable design. Maybe. But only the last 30 years did came up any turntables trying to be "state of the art". So its pretty young an evolution. Shall we give up now? Seems as if quite some people would prefer things to stay the way they are.....

Sorry, - somehow I am missing the point........

I would much more prefer to return to technical facts and hypothesis then debatting about my unability to realize that inevitable need for compromise.

There must be something extremely tempting and attractive about finding early compromises and life in peace with them ever after.

I am sure I am just too simple minded to see and realize that attractivity.
Poor me.

One afterthought: when I mentioned that none of the compromises in my earlier design were detected and weren't detected either by other designers in their design this was NOT ment to be understood as me being a "better" designer. Not so.
I am not a designer at all.
My approach is common sense and clear view, clear focus on the point.
This and as Van Morrison said: no method, no guru, no teacher.
And my design was back then - as will be the new one - NOT a commercial product at all. So all inevitable compromises regarding a commercial product can be spared anyway.

Dear Lewm, well my comment about an idler drive in turntable design today should be clear.
Not really curing one problem ( draw a force vector diagram and give it a deep thought - the bearing of an idler drive (motor force applied to the underside of platter at one point or to the rim of platter at one point) - as it is done so far - is NOT free of horizontal force.... ) and by doing so creating a few others (not just noise...) seems not a good idea.
This is a drive concept of a time long gone by and for a purpose which has nothing to do with quality, but which only applied to broadcast services and disc-jockeys and which is pretty inexpensive to realize. Broadcast stations worldwide discontinued the use of idler drive TTs over 30 years ago. This should tell the story. Furthermore I already said before, that I will never give any comment about any commercial product currently on the market.

As for Vinyl heaven............. I can see paradise, but there is no light....

Dear Mrjstark, indeed - many music critics who never played an instrument and many TT designers who never understood what they are doing.
If we already have so many weak links why adding another.......

But this will lead us nowhere.
I have my points of view - others have their.

Anyone out there who would like to discuss any other technical topic of the complex turntable ?

Well Dan_Ed, you might see it as a complex system. It is to some extend - as I have mentioned before. But not all that bad.
Flame war ? No, I am after results - not opinions.
But it seems very hard to get the message out.

Dear Lewm, I certainly do not want to get into an argument about idler, dd or belt drive. Yes, I agree - everyone has his opinion. And I do not have any problem with other opinion. But I still see this as not about personal opinions but technical principles.
So please do not take the following lines personally, but just as a technical statement.
Believe me - if there would be a direct drive suitable for a really good turntable, I would have used it.
And I still do have access to every possible drive mechanismen and motor in the very highest possible quality. There is no direct drive suitable to rotate a 100 lbs platter with close to zero vibrations and good constant speed - the problem to begin with is the inertia. The high inertia will get into a conflict with the direct coupled motor - same in idler drive. Both drive mechanism do imply total control of the speed by the motor itself via direct coupling.
Thus why all DD platters are fairly lightweight. The DD gets huge problems with high inertia. In any DD inertia is contraproductive. Let me just briefly explain, that there are at least 3 paramount reasons for using a belt drive for a turntable:

- possible lowest vibration transmitted to turntable by thread
- possible highest platter weight
- possible to use high inertia for self-stabilized speed

At least the last two reasons can not be used with idler or dd drives.
Thats why I can not take those two drives into serious consideration.
I know that I do need a super high mass platter which is acoustic dead to reach best possible performance. This should be obvious from the technical facts displayed earlier in this thread.
The idler drive was well explored and professionell researched by EMT and others in the 1950ies and 1960ies.

I guess we all would agree that one of the best possible ways imagined to drive a turntable would be to apply a constant stream of air (without frequency pulse of course.... BTW - thats a drive mechanism I currently am musing about). The next closest approach to that ideal would be the 'en tangent' thread drive with force free lateral bearing.

However - every technican into dynamics and machines will tell you that high inertia will undoubtly provide the most constant speed possible. Why working against a natural force if it gives you a huge advantage for free?
With both idler and DD you have very direct coupling (with a hunchback of problems....) and the speed is direct related to the motor.

Well, I am really sorry, but it is technically and physically obvious that this is not a good idea......

You may use a turntable with a direct drive or an idler and may be very happy with the sonic results.
Thats fine with me.
And it is your opinion which I respect.

Just respect that I would never use either drive and that I KNOW (physically, technically and from experience) why I do not.

Dear Dan-Ed, the turntable stands alone............. alone......... it does not have to be integrated into the audio-system. It does not depend on any other part of the audio chain.
There is no language barrier.
I find it funny that several other posters by now are doing nothing else in their posts than trying to persuade me that my "no compromise" is wrong and futile.
What do you want?
Do you want me - with the words of Lyndon B. Johnson - "rather inside the tent peeing out, then outside the tent peeing in" ?
How about giving the thread some technical input?

I guess I did.

Come on - show me why we are doing and need this and that compromise in turntable design.
Show me technical facts or at least some nice theories why we shall use idler drive or direct drive.
Just telling me that this or that turntable will give me sonic (vinyl) heaven is just not enough.
I am not dogmatic - if there are good technical reason to use other paths - display them here, I will be the first to walk them (I if haven't already).
If someone feels personally attacked because he do own a turntable which maybe have features I have critized or abandoned in my posts- sorry, this is in no way personal.
All I hear are opinions and many comments that I shall give in and accept the need for compromise.

Great.

I thought this is about turntable design and technical issues.

Is there anybody out there who could come to my alliance and bring us back on the track ?

Am I just too stupid or is my english too poor to realize?
Or both......

Can we return to a discussion about technical issues on turntables......
Do someone have some technical input to give.

Otherwise I will rather continue watching FC Barcelona destroy FC Bayern München (which by the way - is today a display of applied superior technique and cool intelligence (but displayed with a burning heart!!) over ignorance, arrogance and selfsatisfaction (football not turntable design....) - go Barca !!!!

Switch on the TV - much more entertaining than this thread by now.

Dear Jloveys, teh Verdier Magnum has some very interesting points. The oil pressure bearing is an extremely good solution for a bearing which is both - able to handle very high platter weight AND provides a very low friction and extremely high damping. Very good. The platter features super high inertia (the large diameter...) but would even be better with an internal damping or a compound (3-5 cm metacrylat or vinyl on top of the platter and at the underside too. thus the platter would be dead quiet and teh vinyl record would see a contact surface with identical density - which is optimal). I see some room for mprovement in the suspension and in a possible counterspindle to make the bearing vector/force free. But it sure is a serious machine with several very strong points and going in the right direction - super high inertia, super high mass in motion .......

Dear Dgarretson, if you want more grip you may need a slightly thicker thread. If you want less grip make it thin. The knot itself - there is no secrect. Just make sure to make a knot which is on one side only. Yes - that way the knot will wander to the outside. This will take some revolutions, but after a while the knot is constantly on the outside of the thread and does not longer bounce against the spindle or platter. You may use any aramid or dyneema on the market. They are cheap and are available in different colors for low $.

Of course there are motors capable to drive 100 lbs platters by direct drive or idler. But not with excellent results - at least not compared to what is possible.

Credible arguments for a light and responsive platter.....??
Very interesting - give me one (aside from being cheap and easy to handle for the motor).

Dear Raul, well we get from you what we got before - loads of technical facts, loads of IMHOs.....

Yes, I can tell you what building materials in what part of the TT are most likely the best to contribute to an excellent behaviour regarding vibration damping and energy transfer.
Why should I tell you. To convince you? Futile attempt from the start.
I guess I have posted enough technical background on the subject in this thread.
A hell of a lot more than you, Teres or Dan_ed together.

But I have learned a lot from you.
Especially one thing: technical facts and physics are sometimes futile in audiophile discussion.

Raul, come on teach us something, come up with some technical explanations why I am wrong and in what aspects.
Show me the way.
And please, technical explanations - not "IMHO"s and not that I shall have respect for others. That I do not bow in awe because of the turntables on the market right now does not mean I disrespect people.

I know that I have stepped on your toes in the tonearm thread and here again.
Sorry.
You are so knowledgeable about these things - why don't you teach us something.
The other TT designers shall just do their homework before telling us that they have found the magic stone.

I did not. All I did is to lay out technical relations and mechnical interactions and that the "complex" turntable does indeed consists of two energy systems.

My other "crime" was that I did insist and still do, that a turntable close to perfection and maybe without compromise can be build.
Somehow this did enerve some people.
As if compromise were a holy cow.
Don't you think that the tonearm you are about to build and to bring to market will be close to perfection ?

Of course in my system is room to improve - maybe as much as in your system.

Dear Raul, if this were a contest (a contest about what ? Knowledge ?) - it would be fairly boring.
Aside from this there is nothing in your last post which requires any response as there are again (as so often..) no facts and nothing which has to do with the topic of this thread but only with personal animosities.
Boring.

Dear Dgarretson, before I get off for holiday, - first of all: very nice set-up you have done with your modificated TNT. There is much more insight and mechanic knowledge displayed in your set-up, than in many comments posted on that topic here in the last days.
As for the denier of the aramide thread.
It depends on your intention regarding the amount of grip you wish to have on your platter. With your set-up the thread does entangle the platter for 5/6 of its circumfence. I would start with a thread about the "thickness" of a sewing-linen. This will run smoothly through the pulley groove of the VPI motor and will give "fairly" good grip without becoming too massive. Aramide thread have become so inexpensive and widely available ( it was a very different situation 18 years back.....) - just get a selection of 3-4 different strenghts. For best comparism - why don't start with a aramide thread excatly the strength/thickness of the string you are using right now. That way you get a direct "result" as for any sonic benefit/or possible drawback of the aramide in your given set-up.
I really am interested to learn about your findings.
Please let me know.