Turntable speed accuracy

The Timeline is giving you one data point per rotation. So what is happening in between those 1.8 second pulses? Your ears just told you something more is happening than just precise timing of the platter. It is like peeking into the room and everytime you see the cat sleeping, but still the canary disappears. The timeline is giving only one dimension of speed control- ie. timing of the rotation period. What is happening during the rotation? The platter could be cogging, it could be wobbling or even have Wow due to an out of round pulley or out of round platter OD.
Beyond the speed accuracy measured by the timeline, as someone else mentioned, speed precision is also important. That means how well does the platter hold 33 1/3 during the entire rotation. This has to be measured either with a test record or with a precision tachometer. The best instrument might just be our ears. Test records have limitations- the accuracy of the center hole in records causes them to be at least one order of magnitude worse than most turntables. (Two order of magnitudes worse than Halcro's DD turntable.)

Thanks Tony,
A perceptive and illuminating commentary :^)

Halcro, great info and thanks for sharing. What you have mentioned has left me scratching my head and always learning.

I know "D" is a little occupied presently but hop he will be able to assist adding to this.

What Tony has mentioned above is another perspective but in referrence to out of round pulley or platter doesn't make any sense to me in relation to yours specially reading what you have experienced.

You have three motors so why not do what I had mention earlier in one of my previous threads.

Place one motor off to the left using your thread and then place another motor off to the right using a separate thread attached but only have one motor working, this will do what Dover mentions above acting as a flywheel and balancing the platter.

When I had my AC3 and spun the platter with no pulley attached it would revolve many times but did slow down fairly quickly but with my Black Knight it's appears to be totally different. Spins allot easier initially and keeps spinning consistantly for a lot longer time prior to actual slowing down, to me this was very interesting in a positive way.

Dear Dover: About thread/high mass platter my AS are not really high mass ( I think are around 12-14kg ) and works really fine with thread and the RX500 performs good as well. Yes, maybe different TT design works different but I can't see very clear the whole reasons about if there are some reasons.

Regards and enjoy the music,
R.

The platter also does not keep rotating very far after the motors are switched off indicating perhaps a bearing designed for friction so that the motors have a load against which to pull?

Halcro, I can't think of a reason for a bearing to provide drag in a turntable- that seems like a Bad Idea to me. Are you sure the bearing is OK?