Tables That Feature Bearing Friction

Dear Dertonarm: I agree in almost all the " main " subjects about TT's BD design.

Yes, it is a very very simple item ( not a rocket to Andromeda. ) to design, almost everything is physics laws aplication with common sense.

Yes ( like any other link in the audio chain ) it must be dead neutral/accurate ( not confuse with analytical, cool, etc, etc )no doubt about. Its job is simple: to run with accuracy/stability at 33/45/78 rpm adding nothing and degrading nothing, a " perfect target " where there are no compromises.
Sounds easy and beautiful!!!

But ( I hate the " but's , but exist. ) how the " science " can predict for example: which material build ( or a blend of materials ) is the right one for the plynth? for the platter? , for the arm board? for the bearing?; which is the " behavior " ( how are its resonances, time of energy dissipation, distortions/colorations. Its behavior is exactly the same at 33rpm than at 78? and a lot of questions that we have to give a precise answer in scientific way and in subjective one too. ) of those build materials when we run the TT along any tonearm with any cartridge? : what kind of distortion/coloration the cartridge is taking from the TT it self? from where comes those " distortions "? exist the " perfect " material? where? why? and I can go on and on.

In a perfect/ideal design we have to have precise answers to many questions and the way to " solve " the " stones " in the road.

Years after you made your TT still have " questions " that you will try to " answer " this year.
Why the physics laws can't help you given to you the right answers when you made the design? maybe because you are not " perfect "? maybe because there are other " roads " to go? maybe? maybe?......?

Like I say in my first post about: IMHO your approach it is not the " only and the best " it is the approach of how you " see " and how you " answer " to the TT design.

I already " see " which one is/was your " answer " to other audio items in your system ( No this not to start a different debate. So, please stay calm about. ) and IMHO not a " perfect " ones. Maybe for you are perfect ( and this is the important subject because you are the one that must live and enjoy any single day. ) but the WORLD is a little more wide than each one of us.

I like this thread where any one of us ( one way or the other for the good or bad. ) are learning many important things that could make that each one of us make a " revision " of our audio/music targets/priorities and what in reality we are hearing in our each one home system: " perfection " or real mediocity or...or...?

Many of us are satisfied with our home system that is full of distortions/colorations ( it does not matters prices or item names ) and IMHO we must grow-up: if the designers, reviewers and audio dealers don't want it or can't it at least we must ask/cry out for it.

Now Dertonarm, sooner or latter we have to put our foots in earth, we have to thing that we don't leave in an aisle way but surrounded by a very wide/different environments and in many cases we can't take out its " influence " ( any kind. )

Regards and enjoy the music.
Raul.

Sorry: think and live at the last sentences instead of " thing " and " leave " .

Raul.

Maybe we have a language barrier. I AM talking strictly facts. It is a technical fact that in order to integrate ANY system, compromises must be made. Insist all you want. You did make compromises throughout the process of designing your table. You have documented them here.

As I suspected, this discussion is moving into the realm of dogma.

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 Dertonarm: I forgot, this thread " discussion " IMHO is only that a discussion not a contest ( technical or not. ) with a winner (s) and defeat people and IMHO too no one ( including you ) can say that in a subject ( like the TT BD design. ) " he " finaly achieve the end top " position " on the learning cuve of that subject.

You point out somewhere: only the " mother nature " make no mistakes, I'm sure and have no single doubt that you are not the " mother's nature ".

I applaud your attitude in your " believes " ( I think that you don't have be on the defensive. ) but that is: your " believes " ( that I respect and that I agree in some ways and issues. ) not other " believes ", maybe today other people ( including me ) can agree on some of your " believes ". I thank you to share it in this forum.

Regards and enjoy the music.
Raul.