Tables That Feature Bearing Friction

Dertonarm, For your consideration, an idler-drive in which the motor force is applied to the underside of the platter, in the vertical plane. Thus no horizontal force needs to be cancelled. No string needs to be chosen or "adjusted". In short, I offer you "Super-Lenco". Take a look at the Saskia turntable. (I know you will dislike the possibility for idler wheel "noise" to be transmitted into the platter, but this is the real world where choices have to be made. Believe me, that turntable is silent.) Put a Saskia on a Minus-K or an industrial isolator for an electron microscope, and you might be in vinyl heaven.

However - once again and for all - it is NOT nessecary in turntable design.

Sorry to use a caloquialism, but I say bullshit! :-)

Since we are on to the drive system in this thread let's use that. For the table that you designed. Did you not find that proper tension on the pulley was critical? Did your math/physics models predict that? How did you find, repeatably, what the correct tension should be?

Let's look at the motor. DC or AC? How about the controller? If you open the doors I bet we can find your compromises. I'm not trying to pick you apart, just your position that no compromise should ever have to be made when building a turntable. The human experience over the last century with building LP playback machines shows otherwise.

Now we can always argue over the compromises that ARE made. That is the sole reason for forums like this.

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.

It would be harsh to own this perfection in the system of so many weak links.
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We already have music critics who never played an instrument - and now this...