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

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.

I don't know about the benefits of achieving maximum "deadness". I've run some informal experiments using different damping materials on my TT's plinth. I definitely found thet there is a point where there is too much deadening which sucks the life out of the music. Yes, you have to address gross vibrations and such, that's not what I'm talking about. AFTER you have got is pretty right this is the fine tuning. Just don't over do it.

Bob