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
I am going to borrow the Timeline tomorrow.

But not all my turntables are in service, so it will take a while to arrive at a full report.
Dev - the Final Audio platter material is aluminium with very heavy copper mat. The thread runs on the aluminium part. I would have thought the copper is harder than aluminium and should be safe but not absolutely sure.
Syntax: "Tweaking a dead cow to a horse is interesting, no doubt, but other Designers made better work."
That reminds me of an old Chinese saying, "ride a cow before you find a horse." For some people their turntable of choice is the cow... for the time being. :-) Or they think they're riding a horse? Or they are just "cowhide lanterns." :-D

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Lewm ~ you don't happen to own a TTWeights table? I've now checked 2 TTWeights tables and both show inaccuracies via the Timeline, would like to have confirmed a third and then can surely say its a design fault!
Looking forward to your findings.
I'll ask this question again since the other post was deleted. What does everyone expect from their turntables when using the Timline device? Absolute zero drift of the laser mark? Here is another way to look at it. Leave the Timeline device on for 30 minutes. If you are comfortable cueing up the same record side twice, do that. So in 30 minutes the platter will rotate 1000 times. Since most tt's are spec'd to have a speed accuracy of around 0.02%, then you can expect to see the laser drift about 72 degrees in 30 minutes. That is 0.2 rotations out of 1000. Is that good or bad? That would seem very good to me. btw- the Timeline maker advertises an accuracy of 2ppm. I take that to mean the Timeline device is about 2 orders of magnitude better than a typical tt.