VPI ADS Versus SDS

I don't miss the point, and you didn't READ my comment.   MY OPINION is that speed stability is about off-centered spindle holes, not A/C frequency.  I am very sensitive to pitch fluctuations and only experience them with off-center spindle holes.  

The controllers clean up or reconstruct the AC signal, regulate it as to frequency and lower the voltage.  My experience is that they provide a degree of improvement and clarity to the sound much as does the addition of a flywheel or a heavier platter (providing more flywheel).  If you have a revealing system and a discerning listener, the improvements are obvious.

Having said all that, the speed of a belt driven TT may still drift from 33 1/3 because of aging bearing lubricant, an aging belt and/or needle drag.  Other factors?  Hence, many users welcomed the Roadrunner tachometer which measured average platter speed over a period of about 3 revolutions.  When brilliantly mated to the electronic drive as was done with the Falcon and later the Eagle, the frequency would be adjusted slowly, but quickly enough as to be done right and not noticed by the listener.   It is a "set it and forget it" system.  (This differs from the instantaneous correction, as in Asian direct drives with relatively light platters, which, according to many people results in a deterioration of the sound.)

IMO nothing has approached the Roadrunner-Falcon/Eagle system which, unfortunately, is no longer available, and not even on the used market--for no one is parting with them.  And just for the record, these were sold at a much lower total price than the competing VPI systems and IMO were built to a much higher engineering and physical standard.  VPI has literally spent years trying to come up with something comparable, but with no apparent success.

As for this new Australian device noted above, despite the pretty page filled with hype, very little information is actually given regarding its actual use, particularly about its "tacho" or "strobe" system, nor about any incremental cost for them.

My Opinion is that speed stability is about off-center holes, not A/C frequency.

If you have a a/c sycro motor Any change in frequency with result in a change in speed.  Voltage drop only reduces the power and sometimes the vibration.

If you can not hear the improvements that  some controllers can make you can save some money.  If you want to state most are over priced that's a economic debate.

If you can build electronics there is a on going diy project on the diy forum.  It all started with a guy who wanted to 2 phase drive a Hurst motor on his VPI. Then Bill, the designer of Phoenix products, jumped in and you can have a unit that can run 1,2 and 3 phases.  It also automatically reduces voltage and many other features.

Enjoy the ride
Tom

The effects of less than perfectly consistent speed screw up the music way before they occur at the level at which they are perceived as pitch problems.  At these lower, less obvious levels, the music looses rhythmic impetus and excitement; lessened feeling of the music’s groove.  My SDS made a very significant improvement to my TNT6’s playback.  I would not consider being without it.