Table speed

Belt drive tables, whatever their other virtues, can easily run fast or slow because of diameter error of the drive pulley and/or belt slippage. Of course in the best tables the error is minimal.

Quartz clock controlled direct drive tables, whatever their problems may be, inherently run at correct speed. Consider that your $25 Timex watch keeps time to a few seconds per year. What's that in percent?

Interestingly, there is a clock that can be incorporated in a piece of equipment that has absolutely no error at all! In a Missile Fire Control System that we designed, serious consideration was given to incorporating a Cesium Vapor Clock which, was then the NBS definition of time. Cost would have been about $100,000, a relatively small sum in context of the entire Fire Control System. Error due to the clock would have been zero, by definition. However, for much less money we used a quartz crystal clock system which is so close to perfect that it doesn't matter.

Buzz-Feiten...or is that too close to digital?

FYI here is some history on atomic clock standards at NIST formally NBS.
http://www.boulder.nist.gov/timefreq/cesium/atomichistory.htm

Rich

Nothing is perfect in life....

Even the ultra accurate ATOMIC CLOCK have precision error......and is not 100% accurate ! With this in mind, I think that all the turning speed of the disc in any CD players in the world are not 100% accurate.

Thank you all for your input. Twl, thank you in particular for enlightening me on guitars. As a hack musician, I probably should have known this, but thanks for the riminder on all of the issues associated with guitar tuning. When all is said and done, I am sure that my untrained ear probably couldn't hear the difference anyway, but I thought this was an interesting way of cross referencing table speed. (the one percent equalling a 6th of a note) Anyway, on with the search and good listening to all.

Rick

I have a rega planar 3, and I recently installed the motor upgrade (mostly because the old motor was 220v/50Hz and it couldn't be used in US).
Now I A/B the rega against my CD player and I cannot hear any speed or pitch difference. I can't remember a/Bing the speed with the old motor.
Perhaps rega solved the problem with the new motor?

In any case I think speed fluctuations will be much more noticeable and detrimental than a constant, relatively small, offset.

There was a thread related to TT stability a few weeks ago that you might find interesting.

http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1058699691&openusid&zz

Yes, platter speed can vary in accuracy from one brand to another. Some brands give adjustable speed control. Better turntables have no real issue with speed problems. Very few are absolutely perfect, but speed regulation under one tenth of one percent is not unusual for a good table. I don't know of any tables that have speed variations of one percent or more. Rega tables commonly run about a half percent fast, and this is pretty well known, and most people don't really notice it.

By the way, I make custom guitars, and a "perfectly tuned" guitar is rarely that. Intonation is nearly always off somewhere on the scale. Nobody in this world achieves total perfection on anything. If there is any variation in string thickness, action height, fret wear, neck set, nut wear, bridge wear, etc., there will be a problem somewhere, and this describes just about every guitar there is. Perfect open-tuning is just the beginning. Controlling a motor speed is much easier, believe me.