Turntable speed accuracy

Speed accuracy is important for me since I jam with guitar while record is playing and that's one of my ways to realize how precise the speed is. If it's faster or slower by small fraction of rpm I'll hear the difference in tunes.

I haven't got perfect pitch and my friends tell me my timing aint that good, but I find piano recordings fantastic for laying bare speed and VTA issues. The words clangy and compressed come to mind when things aren't well, assuming the recording is ok to start with.
Regenerated ac supplies are quite cheap and accessible today and possibly an easy upgrade for tt's with simple supplies.
Love the US$6000 VPI Classic III - Fremer says its one of the most speed stable belt drives he has heard - the supply consists of 1 cap and 1 resistor. Be interesting to run the timeline on one.

Hiho

The drive system on the TW Raven just is not perfect, that's all.

Does the TW raven have any "measurable" wow and flutter, or rumble?

The VPI TNT III and IV with SDS and their motor, flyweel, and belt system have "UNMEASURABLE" wow and flutter and rumble. The accuracy and consistency, is better than "ANY" tape deck or disk cutter. That is "ALL" that is necessary or maters! VPI has not improved since, or has anyone else as far as speed, end of story! Do not worry or leave sleep over this.

The strobe lines on a strobe disk are not "exactly" spaced, and the flashing bulb has ever so slight time delays, which leads to a very slight jitter of the image.

As far as the KAB strobe goes, I agree it is a better way of measuring speed inconsistencies, that "only mater" to neurotic audiophiles! Sane, intelligent, knowledgeable people just do not need it!

You and Moncrief are splitting hairs here, and hung up on "unaudible absolutes"!

How many years was it before side one of Kind of blue was found to be 1/3 of a semitone fast? Maybe Miles knew, but who else? Speed variation "is" noticeable on classical piano "IF" you have played a piano, but typically the audience could care less.

I have read the IAR and Moncrief is a very good "theoretical" technical BSer. You should read his BS about "audible goodness curves", or the Oracle having 377 times lower distortion than a Linn, or his "Wonder" caps. He can weave a technical tale as good as anyone, but he is no Richard Heyser!

I recently bought a Vibraplane isolation platform for under my turntable. It replaced the Townshend Seismic Sink which I then put under my SME motor controller. Isolating the motor controller from vibrations made a remarkable change to the sound of the system.

I understand why isolation under the tt would improve the sound, but I was surprised by the improvement under the motor controller. Could someone explain to me what is going on there?

Also, does anyone have any experience with replacing the rubber belt with a thread on an SME table? Thanks.

Peterayer alludes to interesting questions:

Is speed stability THE most important turntable parameter?

Is there a degree of speed stability below which variations become inaudible?

Is this something that could be tested with reproducible results?

How does a turntable's immunity to outside vibration and ability to dissipate internally generated noise and vibration impact performance relative to speed stability?