Turntable speed accuracy

Halcro - great game eh. Looks like Dokovich has shown the others how to beat Nadal - ie hard and flat if they can maintain it.

Re the bearing, it's a bit of a red herring - I only meant to communicate that in the case of the Final there is high inertia such that if the motor is turned off and the belt/thread is still connected the platter will drive the motor/pulley for a few seconds.

Lewm's capstan is a good observation, the thing that interested me was that if you add a capstan and get more belt/thread on the pulley & platter it will spread the side loading on the bearings of the motor & platter. This would potentially reduce motor bearing wear.

Lewm,

That is a good point about belt contact with the platter. My SME 10 has about one inch of exposed/free belt before and after the motor pulley leaving the vast majority of the belt in contact with the platter. This is in great contrast to some other designs which have a motor on a remote platform 9" or more away from the record platter. Tables like the Walker, the Raven and the Micro Seiki all have a lot of exposed/free belt which is why some owners have switched to thread, I think.

I have not tried the Timeline on my SME or read of anyone else doing so, but the SME tables have a reputation for having pretty constant speed stability and accuracy.

I started this thread a while ago, and I appreciate all of the contributions to it. I have learned a lot. Thank you to all those who have participated.

Hi Peterayer,

I had mentioned in the NVS thread I had tested two and both were off. Using the same TimeLine it was found one was too fast and another was too slow.

Hello Dev,

Yes, I had read that now deleted NVS thread, but I forgot about your particular post. Do you remember how far off the speed was for each of the tables?

According to my KAB strobe, my SME is 0.18% fast, as determined by the fact that four (4) "33" numbers drift out of the red strobe light during a 1 minute test. This was while a record was playing. Unfortunately, my SME motor controller does not have a speed adjustment, so I change belts after about one year and that reduces the error.

I would guess that if you found one SME table too fast and the other too slow that the belts were probably stretched to different degrees. Were these models with adjustable speed on their controllers? If so, did you try to adjust the speed on the controllers to get a more accurate speed? Also, did you listen to each to see if you could hear a difference?

The concept of "belt creep" and what to do about it is not mine intellectually. This phenomenon was first described to me and to anyone else who read it by Mark Kelly. Mark played at designing a bd tt to combat it. The Artemis is a less complex solution compared to Mark's, IIRC. But your SME is well designed, Peter, if it places the motor pulley as close as possible to the platter's edge. Notts recommend this also. That also is a way to maximize the contact between platter and belt. You BD guys should look for posts by Doug Deacon on "tape drive". Doug uses a specific kind of recording tape which he then treats chemically to make one side rough, so it has traction on the platter. Conceptually, this should be better than string, IMO. Reality is sometimes different from concept, however. But Doug claims excellent results with his Galibier turntable.