Tables That Feature Bearing Friction

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.

Dertonarm, thanks for the general suggestion regarding thick & thin, but there are about as many derniers of these synthetic threads as fish in the sea. It would be helpful for this experiment if you could offer a few specific recommendations.

Hi everyone,
I know I will regret posting in response to some of the above, but before I comment on some of what Dertonarm has postulated above repeatedly, allow me to address the original question:

For any given motor/powersupply combination there is a specific load against which it will work producing the least vibration/smoothest rotation. This is, strictly speaking, only true for a motor which has perfect spindle bearings. They are another source of irregular behaviour, particularly since the load on a belt drive motor pulley when used with a thread is rather high(compared to the tension required if a rubber, neoprene, silicone... belt is used). It is possible to address this problem, at the price of complexity and noise(i.e. counter-pulley for the motor spindle...other options exist).

Off course stylus drag isn't capable of slowing down a platter AND at the same time modulating the deceleration(or the acceleration!) at the exact frequencies that are being played back at that moment. The platter acts as a low pass. Nevertheless, stylus drag is NOT constant and therefore requires lost energy to be fed back into the system at an ever changing rate to maintain absolute speed, requiring constant acceleration/deceleration. If the platter is loosing energy due to additional "drag", be it generated by an eddy current brake(no noise added), a felt brake, a paddle running through a silicone bath or a particularly lossy bearing(i.e. the DPS turntable), the influence/impact of the losses generated by the stylus drag become smaller.
Increase the drag tremendeously and you will get the influence of stylus drag below the threshold of audibility(let's just say for a moment that there is such a thing...)*.
You need to increase motor torque(meaning, all other things being equal, increase motor noise) once the losses become too high, both to be able to maintain target speed and to bring the platter up to speed within a reasonable amount of time.
*The same can be achieved by increasing platter mass/inertia, BUT the remaining speed variations will be lower in frequency and higher in amplitude if no means of damping(same as aditional drag, sorry)is employed. Low pitch variations are more obvious/bothersome to some than they are to others.

Since amplitude and frequency of the platter speed variations can't be reduced to Zero, any turntable will be compromised, unless it's platter would feature infinite inertia, in which case all other factors(motor, idler, belt etc.) become obsolete, since nothing can move an infinitely inert structure.

The insistence on the superiority of Dertonarm's super heavy platter driven by a lossy drive/"slipping" thread is hard to understand, particularly if we apply the laws of physics, as continously demand by the master(couldn't resist that one ;-) himself.

If the thread is allowed to slip while it is driving the circumference of the platter, slippage will (likely)occur at the pulley too. Even if the slippage was constant, and it is NOT(according to physics, keyword:"stiction") , slippage on both the driven and the driving surface will result in chaotic behaviour, COMPROMISING the evenness of energy transfer.

If, as some turntable manufacturers have done, the platter speed is monitored and used to control the motor, hunting and pecking is inescapable and only the chosen feedback time constant, the platter mass, the motor torque and the little bit of stretch left even in Aramid or Dyneema threads will govern the speed variation amplitude and frequency around the nominal target speed. And if there is belt/thread slippage or an out of round platter, the "error correction" will have to work very hard.

Dertonarm stated that neither direct drive nor idler drive was usable to build a turntable with high mass/inertia platter. Oh boy... we are mostly listening to shitty records cut on Neumann lathes, some of which use a Technics SP10 MkIII motor(albeit driving a 40kg, large diameter platter)
The Onkyo PX-100M, an eddy current direct drive tt features a 24lbs platter(without the mat) and is an excellent deck.
Other examples in conflict to the above statement were mentioned by Chris Brady.

What does a super heavy platter buy the designer other than inherent higher frequency speed stability? Problems!
You'd be surprised how much wobble/tumble can be detected on platters even if the bearing tolerances are super tight(the Continuum Audio site once had some indepth analysis graphs and animations)
Dertonarm will likely reply that an airbearing is the solution, but it isn't(it's a compromise too). It minimises bearing noise and friction(a major problem with super heavy platters) but can't restrain platter tumble as well as a pressurised oil or grease bearing. For what it's worth, essentially all industrial axial airbearings for heavy loads are made for much higher rpms.

Dertonarm suggests/requests the side load on the platter to be zero. Very good(unless a spindle bearing à la Bill Firebaugh is used)! But if you do this by putting a counterpulley opposite of your driving pulley and maintain not only the distance but also the diameter of the counterpulley, there is a strong risk of all 4 "free" thread sections acting as strings, resonating at the same frequency. Any such behaviour will wreak havoc on the smooth operation of the motor as it changes the load it sees rapidly. Put a break on the counterpulley or change the pulley diameter and the distance accordingly and the problem is solved.
Off course, once the platter is made heavy enough, that becomes neglectable too... depending upon your neglectability threshold.

My conclusion: Dertonarm's way is one way, but not the only way. It is, like all ways, compromised(I wouldn't dare calling it flawed).

A few last words on how "commercial" designers/engineers are often described here and in other forums.
Yes, there are some(too many) that do not have a deep understanding of physics or electronics(not to mention the growing number of copycats). But just as many do and they are into it because they happen to share other people's(be it customers or colleagues) enthusiasm for music and all the gadgets that allow us to enjoy it in it's preserved form. It is simply not true, that all of us think with a target price tag in front of our eyes first. It is simply not true, that all of us think: "yeah, I guess that'll do..." And that is a FACT.

Finally, it is downright ARROGANT to belittle designers who are capable of coming up with a component that delivers 95% of what is currently possible at 10% of the price. Yes, it is all about compromises and ESPECIALLY an all out assault on the state of the art will eventually run into facing this as well.

Happy Easter,
Frank Schröder

Dear Dertonarm: This is not a contest ( like you want to be ) on who have the reason or who knows more about.

I posted that I'm not ( yet ) on the TT design. Right now I don't know if there are better alternatives and which ones are even I can't say that your is the " one ".

Right now I'm a " spectator ". I have several " ideas "/common sense that are the ones that I will follow when we start our TT design.
What have I on hand?, almost nothing. My TT design is on " desk " waiting for like the amplifier one. Each thing at its time.

I'm not saying that your approach is wrong what I'm saying is that it is not " the best and only way ". In the time we already finish our research on the TT and start the design, tests, execution, tests, tests, test, then I will have a more precise arguments that exist other alternatives that can even and can outperform the ones that exist today including yours, not before: I don't have the " cads " yet.

No, you don't do nothing ( steped on... ) in the FR that is a " so so " design even with its own FR cartridges. No, I don't want comeback to this subject, I point out only because you name it again. I posted that when we obtain the patents on our tonearm design I will share with everybody, not before, science is science.

+++++ " 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? " +++++

I don't need that you convice me, normaly I take the steps by my self to convince me about any subject that has interest on what I'm trying to achieve.

I don't care and means nothing if you name some materials with out scientific tests that prove/establish that that combination of build materials and its inter-relationship ( platter, plinth, bearing, arm board, footers, etc, etc ) are dead NEUTRAL below any real playback work conditions.
I think you can't do it, I mean that you don't have it, do you? .
Now, if you have it I don't need that you tell me, sooner or latter I will find the answers ( maybe a different ones from yours and maybe some like yours. ) about when we are in deep in our design.
I ask about only because you don't touch this " main " TT deign factors. I wonder why?, perhaps another un-finished/futile TT design?.

IMHO all our un-finished designs ( protoypes. ) have a very important " steps/role " in the final product and that role is that through these prototypes we can achieve our targets to build the real FINISH product.
I have some Phonolinepreamps and tonearm prototypes where I can " read " the different steps that bring me to the final product.
We have many differences in our way of thinking ( between you and me. ) and one of them is that I never think that I'm at the end of the audio item learning curve final design, at least I never experienced that I'm there.

I have my dream phonolinepreamp design like the tonearm, cartridge, TT and amplifier ones. These " dream designs " are perfect ones and wonder what? are commercial ones too but we need time a lot of it to make those " dreams " come alive but my final " prototypes " are a good step on the right road.
I can tell you that if I was Matushita Corporation where I can have any kind and any quantity of resources for audio projects then maybe in two-three years those " dreams " comes true but we are two-three persons that make this job in our free and just because we like it and enjoy what we do about.

Anyway, like I already posted go on: many people here are having fun and that's good. It will be " futile " if I try to go on. In good shape: thank you for your time.

Regards and enjoy the music.
Raul.

I thank all the participants on this thread for sharing their knowledge and experience. Sitting on the perch of not being willing to build my own TT, and not being willing to spend ultra-bucks to buy someone else's summum, and being quite happy with what I have, I am very happy to hear a variety of opinions and experience because I am learning a lot from the discourse. I think if EVERYONE took a step back, they might learn something. Because people are coming at this from different perspectives, they seem to be getting their noses bent out of shape. Almost everyone here except Dertonarm is coming at this from the side of what is commercially viable (either because they need to make something commercially viable, or because they need to buy one which is made by someone else). Dertonarm is coming at it from a different angle.

Years ago, I read the Teres Project archives. They were extraordinarily enlightening to me at the time. I found dissenting opinions, and well-meaning hypotheses which turned out to not work, but in the end a lot of openness to challenging the existing ideas in order to create something better. In the end, those better ways were created (and I would suggest Chris Brady and recent Teres model purchasers believe the Teres Project results are still being improved upon) through hypothesis and trial. The results were that through astute selection of materials and drive system, an excellent TT could be built which was less expensive than the otherwise self-declared state-of-the-art. I would assume that subsequent models higher up, which garnered much praise by people with great systems improved upon the first renditions. It is obvious through Chris' assertions here that he believes his new DD system, and perhaps others', improve(s) upon those highly-praised BD TTs). I am sure they do. The fact that they are still being improved upon means that everyone is finding better and better ways to skin the cat. Dertonarm's main point is that the cat is still the cat (unless, of course, it is Schrodinger's cat, in which case, it may not be), and that there must be a 'best way' at some point (assuming that everyone's measure of 'best' is the same).

I think that Dertonarm will not deny, disavow, disagree, or demean anyone's opinion that a given DD motor driving a high-mass platter can sound better than a given belt-drive high-mass platter system. I am pretty sure that what he is saying is that he has not found it to beat his belt-drive high-mass platter and he has found the compromises in the DD method to be greater than the compromises in HIS BD HM system. Dertonarm has, in every thread, refused to comment on what he thinks sounds better (partly because it is beside the point I expect), but consistently appears to be looking for someone to provide technical input or results rather than an opinion or the result of System A having been better than System B (which is not so much a demonstration of physics as a demonstration of implementation). Trying to critique his results as invalid because he still finds compromises in it is also beside the point.

So far, the fault I find in Dertonarm's discourse is the assertion that DD or idler drive would not work with "highest possible platter weight" and using "high inertia for self-stabilized speed." It may be right, it may be wrong. It is, however, not defined nor supported. If there is a mechanical slippage system (slipping belt drive) there is, by definition, a compromise. In my opinion, the PERFECT implementation of a TT would not use mechanical slippage. It would also not depend on electromagnetic slippage. In a perfect system, it would be pure 100% speed-stable drive. I am assuming his assertion is based on his experience that mechanical slippage may be a smaller compromise than building a system of electromagnetic slippage with no mechanical slippage. In any case, let's see the technical reason why such is the case. I, for one, would expect that one could build a very very good DD HM system given enough time and enough resources - though in the end it comes down to motor speed/torque stability and whether that stability is greater than the speed stability offered by a 'clutch' system of thread slippage.

While Dertonarm's conclusions appear to be 'dogmatic' to some, they appear to be the result of trial and experience. His tone may be dry, and that seems to antagonize some people, with somebody now suggesting he has an 'agenda' (similar to the way some people 'have an agenda' with tubes and OTLs, and others with single driver loudspeakers?). I personally do not see 'constant demeaning of dissenting opinions' so much as I see challenges to demonstrate that opinions are backed with technical results. I am sure that if someone could prove that a DD with high mass platter had better speed stability than a thread drive, many would be interested (including Dertonarm). It just happens to be that while some people profess that such a thing is possible and they have heard it with their own ears, someone else thinks it is still a method with less accuracy than is available than through what he has done himself.

I would encourage everyone to look at these discussions the way they might if they had participated in the Teres Project Archives email exchanges. There is nothing wrong with dissenting opinion (and I for one do not see Dertonarm's commentary to demean dissenting opinion), but Dertonarm's whole point is that he is striving to improve upon what exists, not prove that one existing thing is better than another. His question to all is whether anyone can demonstrate that one method is, in a technically definitive way, superior to another.