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Turntable speed accuracy

There is another thread (about the NVS table) which has a subordinate discussion about turntable speed accuracy and different methods of checking. Some suggest using the Timeline laser, others use a strobe disk.

I assume everyone agrees that speed accuracy is of utmost importance. What is the best way to verify results? What is the most speed-accurate drive method? And is speed accuracy really the most important consideration for proper turntable design or are there some compromises with certain drive types that make others still viable?
peterayer
halcro's avatar
halcro
2,664 posts
 
I decided to try another method for the thread drive.
I connected a thread to the platter and one motor (green French silk).....whilst another thread altogether connecting the other motor to the platter (black French silk).
2 THREADS
Re-calibrated the motor-controller using the Timeline (needed to increase the speed due to stylus drag) and listened to the previously warbling flute on the Massenet Le Cid.
No warbling now :-)......and the Timeline is slightly more constant than with the rubber belt.
GREEN BELT
BLACK BELT
dover
2,333 posts
 
Halcro - looks like the 2 threads are touching. If so you might want to put a shim under one of the motors to lift it slightly and separate the threads. Would be interesting to try 1 motor/thread. Cheers.
aoliviero
271 posts
 
Empire TT's based on AC motors using belts.
halcro's avatar
halcro
2,664 posts
 
Dover,
I kind of like the idea of not placing lateral loads on the platter bearing....and this arrangement is working so well I don't know what there is to gain with the one motor?
What harm do you think there is if the two threads touch?
atmasphere's avatar
atmasphere
12,126 posts
 
Which Empire TT are you referring to? AC or DC drive ,belt type?

The Empire is of course AC synchronous drive. But most of my experience with it is actually with our variant of the machine, which we have been doing since the mid-90s:

http://www.atma-sphere.com/Products/#Atma-208
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