How important is low W & F performance anyway?

Dear @phoenixengr  : How important?, as a stand alone measure could means very little about quality performance  TT as a whole audio item and that measure depends too of the standard protocol to do it as: DIN, IEC, JIS and the like. 

A TT is surrounded of several other important parameters as S/N, speed stability, arm board isolation, plhynth characteristics, footers, etc.

Now, a question to you: can you be aware ( everythibg the same ) between 0.03% and 0.0018%? and how idenfify you that difference by ears?

I can’t do it and for me is not important as a stand alone measure and as other member posted the final result during playing is what it matters when every parameter is involved.

In the past/vintage specs of TTs in Japan was way important due to very hard competition in between manufaturers and audiophiles were looking and had atraction by overall specs/numbers in those TTs.

Instead today almost no one cares or as @lewm posted not even understand its significance.

Btw, excelent achievement your results in that motor controller.

Regards and enjoy the MUSIC NOT DISTORTIONS,

R.

Now, a question to you: can you be aware ( everything the same ) between 0.03% and 0.0018%? and how identify you that difference by ears?

My hearing is not very good so I'm not a good example for this.  The mfr is an audiophile and musician and he could hear differences that I could not.  When we were tuning the control loop, I gave them ability to modify it in real time while they were listening to music and the person making the changes did not inform the listeners when he made a change or what change he made.  The parameter he was changing was the gain in final output stage;  it did not change the W&F measurement significantly (the overall reading stay centered around 0.005%) but it did change the spectrum of the signal derived from the optical encoder.  The sidebands stayed below -60dBc but the primary bump in the response shifted location (closer or farther away from 3125 Hz).  The listeners reported a subtle change in the voicing of the table from "more analytical" (higher gain) to "warmer" (less gain).  We ended up adding a user adjustment for this to customize the voicing of the table to enhance or compliment the user's system or to match their preference and set the factory default level to midway between the two.

@phoenixengr 

Multi track tape machines typically have a wow and flutter spec of .1 % or higher.

The revered Scully lathe was .2. 

Were the turntables in question using the same test specs as the manufacturers, IEC, CCIR, DIN? 

@billstevenson 

Congrats on a good find, and that it measured so well. I tell others, they are solid, a darn good choice for someone getting started in Vinyl.