Direct drive/rim drive/idler drive vs. belt drive?

The primary hurdle to jump with belt driven turntables is their inherent belt creep.

It is best described here...
http://db.audioasylum.com/cgi/m.mpl?forum=vinyl&n=694178&highlight=belt+creep&r=

Albert,

Mark makes the controller for my Saskia idler drive, and I can say firsthand that he looks at things from a critically analytical viewpoint. That said, he owns idlers including the Garrard 301, Commonwealth and others, and he can fix the speed on pretty much anything. Basically, he may be saying that the Garrard needs a good speed control. ;)

Best,
Win

Albert,

I may get into trouble here, but I am increasingly convinced that the micro-dynamics of analog playback, in particular, hinge partly on things we have yet to measure. I thought I had built a great turntable, but somehow I inadvertently improved the dynamics of it without trying by implementing a change to make assembly easier. We may have figured out a lot about audio, but I really believe there are still volumes left out there for us to discover. I suppose the goal should be not to know everything, but to not know as little as the competition...assuming it is about competition, and I'm not so sure that that should be the end goal. Me? I'll settle for good sounding no matter where it originates. :)

While we are getting offtrack...

Mine comes in memory of Colonel Sergei Ivanovich Mosin. He had a fascination of mechanical things enough that the rifle bearing his name has survived from 1891 til this day in one form or another. I respect him because he fully appreciated and practiced the principle "form follows function" even before Louis Sullivan wrote about it.

Win

Back on track...

The discussion so far has been about torque, but in my opinion the most critical component of a turntable may be the platter. With all three types, belt driven, idler driven and direct drive, the platter can be the make-or-break piece because it is the final interface to the record, it is key to how inertia works and it is the interface to the rest of the mechanism. That said, I really believe that a turntable should be seen as an entity because, like the audio chain in your system, it is only as good as its weakest link. There is no single part, no matter how seemingly insignificant, that should be overlooked. Designing a decent one is easier said than done for certain.

Win

"Similarly if a manufacturer sends me several samples of a high cost three phase motor and says "do your best then bill me" the results can be pretty good."

I resemble that remark. Yuk. Yuk. ;)

I do have a habit of sending motors to Mark, and leaving the task open-ended. It can result in sticker shock, but the result can be stellar.

An external rotor three-phase eddy current motor that has has a 90W draw can be very inefficient, but the payback is in extreme smoothness, and also wonderful dynamics. So, I agree with others that a decent motor is key to high performance. In the case of Saskia, my turntable, the platter gains equivalent mass from this approach, too. The external rotor provides this to a point that when used with an idler it is the equal of a belt drive that has a platter that weighs several hundred pounds. The motor counts for a lot, but the platter can be further tuned to enhance inertia even more. Then, there is the spindle, bearing well and associated parts which also play important roles when it comes to ruble control, dynamic braking, evenness of play, etc. Again, if any aspect is neglected, performance suffers in one way or another.

Win

"This is in COMPETE contradiction to the 'Platine Verdier' tt which on purpose applies a constant bearing friction-load to stabilise their high-mass platter."

By my way of thinking, the Verdier approach is far more elegant. The bearing friction load, if that is what to call it, combined with compulsive obsessive tight tolerances can act in a way similar to a grease bearing by also creating a dynamic brake of sorts. The beauty here is that it doesn't have obstacles, like misaligned magnets to deal with, or any influences that might be caused by them. It's a case of less is more in that less complexity is involved to achieve a result that may in fact be superior. It also indicates to me that the manufacturer has taken more care in a traditional approach, if his result is an extremely good one.

A manufacturer can use tricks like magnets as a workaround for the unwillingness to spend extra for precision machining or better materials. I'm not saying that any particular company is doing that, but I do see the possibility.

Summary: I don't buy into magnetic levitation for platters.

Win
Saskia Turntables

Lew,

Maybe I spoke out of school because I believe I am the one who may have confused the issue. Unlike either Clearaudio or Verdier, my turntable uses an eddy current motor. At least, I believe neither of them uses one. Anyway, I also am a believer in the use of hydrodynamic drag, as Mark calls it, so any reference to friction drag was maybe the source of confusion.

Win
Saskia Turntables

Mark,

I believe Lew figured out (on). Now, he has the only Lenco that truly works only on demand. ;)

Thanks for saying what I meant regarding hydrodynamic drag. What I was eluding to is the constant war of trendy vs. innovative. It is easy to write copy that promotes a design, but it isn't so easy to create a design that stands on its own. That is what audiophiles should really look for in products, but it is hard sometimes when ad copy clouds the issue.

Win
Saskia Turntables