Turntable speed accuracy

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?

Use of a capstan, etc, or any strategy that increases the area of contact between the belt and the platter is a good way to combat "belt creep", the bete noir of belt-drive tt's. This is why I am skeptical about 2- and 3-motor arrangements; of necessity, the platter to belt contact area is reduced in both cases, even compared to conventional single-motor arrangements. This is also why I really like the Artemis SA1 turntable, in principle. (Never heard it.) It uses a single motor and a capstan so that the belt (looks like tape) is nearly completely in contact with the circumference of the platter.

Dare I say that a device like the KAB might be superior to the Timeline for detection of very transient deviations in speed? OK. I said it.