Turntable speed accuracy

Let me clarify my one statement a little better. Cueing up the tonearm is a one time event that may or may not cause the laser mark to move. It is not part of the cumulative error. So over the long term it has little or no impact on the results. Unless something funny is going on with the motor controller, the laser mark should drift slowly in one direction over the 30 minutes. That is the cumulative error.

Hi Tony,
I have left the Timeline running for an entire album side with zero drift.
If you go to YouTube and look up the Timeline video (not mine).....you will notice on the demonstration that his turntable.........demonstrates a significant drift when the tonearm is lowered.
The Timeline is the scientific device that conclusively proved that 'stylus drag' is a reality rather than a theory.
I cannot believe that my Victor TT-101 is the only turntable which can maintain this kind of speed accuracy?
There must be many other brands.......perhaps mostly of the quartz-controlled direct drive type......which are similarly capable?
If this is the case.......then we should have the right to expect this kind of accuracy from our turntables.
Even with my Raven AC-2 with thread drive.........the drift with a stylus in play is only 0.5mm per revolution from the wall mark. If I adjust the speed on the motor controller one step UP.....it then runs fast by 1mm per revolution. But these are both constant deviations which indicate that the turntable is maintaining consistent speed.......just not exactly 33.33rpm. If the motor controller had a finer adjustment......I could get it spot-on.

The Timeline is a wonderful instrument IMHO and it is not correct to believe that turntables cannot match its accuracy?
I await the day when you actually try one on your turntable.......it can only help you :^)

Hi Halcro, That is excellent news. So is speed accuracy something that was once mastered and now lost on more recent tt's? How do we get it back? Do you feel you lose something with the thread drive since it drifts a bit? I would think not, but your opinion/experience here would mean something.

Dear Tony,
You wrote, "the laser mark should drift slowly in one direction over the 30 minutes. That is the cumulative error" Yes and no. Yes, the drift of the Timeline laser over time is the cumulative error, but no (IMO), the laser may not drift only in one direction, as I wrote above. It could conceivably drift in either or both directions over a 30-min time frame. Therefore using the cumulative error over time as a standard might be misleading. You've got to sit there and watch that laser every single revolution.... (You are getting sleepy.... Your eyelids are growing heavy... You are in my power... You will do whatever I say...)

Hi Tony,
Yes....I think speed accuracy was indeed mastered over 30 years ago but as I mentioned elsewhere......with the dominance of belt-drive over DD turntables due in large part to the Linn propaganda and the reviewers who championed it.....'speed accuracy/consistency'.......never was mentioned as a critical factor in their design philosophy?
How do we get back to it?........I think discussions such as this is certainly one of the ways and thanks to the Timeline......I hope more designers and manufacturers will be able to judge their successes or failures and hopefully make some corrections?
'Awareness'.....is our best hope?
The .5mm speed drift I am seeing on the Raven AC-2 is almost negligible.
For instance.......the Victor TT-101 allows me to speed up or slow down, the actual speed of the platter in 6Hz increments.
33.33rpm apparently gives a pitch of 440Hz which is the de-facto standard
pitch for orchestras.
However many of the world's orchestras use a pitch either 6Hz or 12Hz up or down from this?
When I adjust the speed on the TT-101 to 6Hz lower (33.25rpm).....the drift from the wallmark is 5mm every revolution and when the speed is increased to 33.40rpm (6Hz higher).....again the drift is 5mm per revolution.
So the Raven.....running at 0.5mm per revolution could really be called...'spot-on'?

And Lew is right Tony......the Timeline is not so valuable in terms of 'cumulative' drift or speed error (as even a 6Hz pitch deviation will add or subtract 5mm drift to each and every revolution which will appear quite dire over the full side of a record).....rather it is the instantaneous speed drift due to stylus drag which is valuable for us to know about our turntable's performance?
Instead of 'fear' governing our apprehension of the Timeline and what it will reveal about our turntables.......we should really welcome this information.
Knowledge is power....and ultimately the more we know about our system's objective performance.....the more equipped we are to effect improvements?