Turntable speed accuracy

Dear Thuchan: I think you have a wrong concept of neutrality/accuracy on audio devices.

IMHO any audio device should let pass the LP/cartridge signal " untouched " and this means with accuracy/neutrality: IF THINGS ARE THAT THE THE TRACKS ON THAT LP ARE WARM/COLD/LIVELY/DYNAMICS/BRIGHT/DULL/DARK/ AND THE LIKE WHAT SUPPOSE THAT ANY AUDIO DEVICE/AUDIO LINK IN THE WHOLE AUDIO SYSTEM CHAIN MUST DO IS TO PASS ALL THOSE LP MUSIC RECORDED CHARACTERISTICS WITH NO ADDED DISTORTIONS/COLORATIONS BUT WITH ACCURACY/NEUTRALITY.

ALL THOSE MUSIC RECORDED CHARACTERISTICS came/comes in the LP and in theory are not part or be/bee need development by the audio links: what you hear must be what is in the recording: adding NOTHING!!!!! or do you think that your system is so good that can improve what comes in the recording?, no way my friend no system can do it!

Do you think that all those additional " stuff " in your Micro Seiki improves the sound?, NO only change and add different distortions with no real improvement.

Regards and enjoy the music,
R.

Tony, What I meant was that in direct-drive turntables, the motor, the drive system (aka servo), and the platter together form a closed system. So indeed the mass of the platter has everything to do with it. If you don't see what I mean, try removing the platter from a direct-drive turntable. The result will be a pronounced herky-jerky motion as the servo goes searching for its proper load. If you dramatically increase the mass of the platter (yes, "m"), the servo can get similarly screwy, slow to correct for off-speed moments, but it is less easy to see. It is the servo that tells the motor "how much acceleration is enough" to get back to equilibrium.

None of this is to contradict what you say about LPs with off-center holes (i.e., most of them). That's a big, important, and separate issue.

Thanks Dover, Chris, Thuchan & Banquo,
I appreciate your encouragement :^)...... John Gielgud (blush).
Dover is from New Zealand.....so of course I sound like an orator to him:^)

I was going to follow up with a video of the Raven AC-3 under test.......but I don't think it's fair?
Everyone can test his own turntable once armed with the Timeline.
There will be some shocks?

Tony,
The TT-101 does in fact reach its correct speed within a revolution as seen on the Timeline.
The actual specification states that 'starting time' is within 0.6sec.
Starting torque: 1.2Kg/cm
Speed deviation: 0.002%
Drift: 0.0004%

There appears to be some confusion about the functioning of the quartz locked positive and negative servo control of the TT-101?
It does not compensate for a speed deviation over a complete 'revolution' or series of 'revolutions'.
In other words......if there is a slowing down due to stylus drag........the servo does NOT speed up to 'compensate' for that 'lost' time and thus keep an 'average' continuum?
The servo does not know how many revolutions it is completing in any listening session....nor does it care.
It cares only about 'instantaneous' micro speed control.
What this means, is that if there were a slow-down due to stylus drag at any point of a record's playing cycle......that error would be permanently imprinted on the Timeline 'Blutak' marker on the wall. And any extra deviations would be accumulative so that the laser line of the Timeline would 'drift' further to the left with every revolution.
This you will appreciate if you ever use your own Timeline on your own turntable?
It truly puts into perspective the performance of the TT-101 which you have witnessed on the video?

H Lewm, yes, you are correct. That is called cogging. I'm sure BD motors do it too if they are unloaded. You just can't see it with your eyes because they spin too fast. That is what I was saying before that designers use mass as a damper- mass damping. All motors have some level of cogging, or ripple. Even your car engine has it as each piston fires. The flywheel smoothes out those ripples just as the tt platter smoothes out the ripples from the motor. The typical tt specs showing Wow&Flutter below 0.03% shows how well these massive platters are doing their job. btw, the more poles that a motor has, the smaller the ripples. I notice some of these expensive tables have quite sophisticated motors. Caveat Emptor always applies, but I think you are getting what you pay for in some of these expensive motor designs.