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

O.K. here is one for all the physics majors and engineers.

Does a high mass platter being belt driven offer the same steady inertia/speed as a direct drive or idler drive?
Is the lack of torque in the belt drive motor compensated for by the high mass platter. Object in motion stays in motion etc. Or are there other factors to take into consideration?
I am considering building up a Garrard 301 or Technics SP10, but is it all nonsense about the advantage of torque.
I am aware that the plinths on these tables can make a huge difference, I've got that covered.
My other options would be SME20 or Basis 2500 of Kuzma Stogi Reference etc.
If I have misstated some technical word, please avert your eyes. I don't want a lecture on semantics, I think everyone knows what I mean.
Thanks in advance.
mrmatt
mosin
410 posts
 
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
lewm
13,275 posts
 
As one who has just wasted the better part of a beautiful hot Sunday afternoon trying to assemble my Lenco in its slate plinth, only to fatally smudge the professional paint job on the PTP3 (it will need to be redone) and find that I had ordered the wrong very fancy push-button switch, I am in no position to take issue with anyone else's feaux pas. Who knew that "off-(on)" in the Mouser catalogue is not the same as "off-on"? I now know. This is not really OT because I am talking about assembling an idler drive tt.
quiddity
119 posts
 

Lewm

Win correctly described the influence of the Verdier's deliberate use of a trapped layer of lubricant to contribute hydrodynamic drag which lowers the Q of the platter / belt system.

That he did not use exactly those terms is neither here nor there - I have chosen my words to highlight the difference between two types of resistance which are usually lumped together as "friction".

Mark Kelly

BTW (on) usually means momentary.
mosin
410 posts
 
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
lewm
13,275 posts
 
Thanks, guys, for putting me on the right track as to the theory of the Verdier and the harsh reality of pushbutton switches. Sadly, I now see that pushbutton switches of the "push-on/push-off" variety are rare indeed, and I need to find one to fit the 5/8" hole that I already drilled to accommodate it. As Win and I discussed, the switch I did buy will work fine, IF I want to stand by the turntable with my finger on it whilst I listen to music. It does, however, fit the hole I drilled. Live and learn.
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