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

My experience with coreless motor is not limited to just the Pioneer as I have several turntables here that exhibit this silky smooth quality. The Pioneer is better to illustrate the distinctive quality of coreless motors even in an inexpensive model. I believe the later Pioneer models, the "L2" series of turntable, such as PL-50L and PL-70L all converted L2 to use coreless motor with the same specs, all employing their trademark feature "Stable Hanging Rotor" SHR, basically a fancy way of saying an inverted bearing. Anyway, I realize many top or almost top of the line models from various brands used coreless motors such as Kenwood L-07D, Sony PS-X9, JVC TT101, Yamaha GT-2000, PX-1, Pioneer PL-70LII, Sansui XP-99, et al. I owned neither so obviously I am drooling here. I am not saying only coreless motors are good. It's just that whenever I detect this kind of smooth sound, invariably it's a turntable with a coreless motor. JVC have some core motor tables approach the smoothness I crave for - I haven't listened to my SP10 for a while now. That's why I reserve the core motored tables for tape-driving purpose as the tape smooths out the tiny bit of cogging or whatever you call it for the passive platter.

Raul, I admire your forward thinking. Keep up the good fight. Yes, sometimes audiophiles got what they deserve, un-innovative products.

After chiding someone on VA over miunderstanding servo loops I should correct an error in my description of the Denon.

Where I said "it also employs a PLL controlled servo loop to slave the coil drive to a motion dependent signal...." I should have said "it also employs a servo loop which adjusts the coil drive, using a motion dependent signal...."

The master is the quartz reference.

Mark Kelly

Mark,
since you ARE in the know about PL(L), servo loops, 3 phase conversion, quartz reference, current supply ability, and on.
Have you any comment on the SME controller implementation, from what I posted earlier or any of your own more detailed insights?
Axel

Axelwahl

I don't have enough information to make an informed judgement about the SME's controller implementation.

Mark Kelly

Hiho, for the record, the Empire does not go off speed if properly serviced, and can be expected, once serviced, to run for years without further attention. I have seen the motor angle being so poorly set that the belt engages the wrong part of the motor spindle, and I have seen motor spindles so dirty that the diameter was increased. The actual spec of the stock machine is impressive- well within the specs set by the best of the DD machines.

Lew, I don't know all of what Warren put in his mat, but I understand it contains an aluminum disk, and there is a thin Sorbathane layer where the mat meets the platter, so the material is not amorphous.

Although it is by far the best mat that I have heard, it is obvious that it could be a lot better- otherwise damping the platter would not have the rather obvious improvement that it does! OTOH it might be that the best we can hope for is a platter pad that can do what I said- have the hardness of vinyl so maximum vibration transfer without reflection is achieved, and otherwise maximum deadness.