turntable speed control

If you're going to quote me, please quote enough for it to make sense.  What I wrote was:

"More importantly, I believe, we can hear things that we cannot measure.  That is why, despite the great (industry approved) measurements from relatively inexpensive direct drive TTs, most careful listeners know that belt drives (which may measure worse in some respects) sound better."

Problem is that it takes quite an expensive DD with a heavy and non-resonant platter to approach and even surpass well designed belt drives.  There are a few you can buy today, including the VPI.  But the run-of-the-mill DDs with lightweight and ringing platters just don't do it.

lewm "Melm wrote, "...belt drives (which may measure worse in some respects) sound better." This is so so wrong and short-sighted. Yet, CLeeds agrees with him."

As melm pointed out to you, that isn't exactly what he said.

" Well designed and implemented turntables of any kind sound better than those that are not well designed and implemented. "

I agree completely! I've owned some great DD turntables even though I've been using belt drive for years. I've heard the VPI DD and it's terrific. But as melm also points out, it's an expensive and complicated undertaking to make an outstanding DD turntable. Ask Harry Weisfeld - he's made 'em all: belt, rim, DD. Who knows what he'll think of next?

Melm and cleeds, My apologies.  I was to some degree playing for laughs.

Anyone tired of fiddling with belts and belt tension might want to consider any of several vintage Japanese direct-drive turntables, the creme de la creme, not the bargain basement ones, as an alternative.  Examples include Denon DP80, Victor TT101 or TT81, Kenwood L07D, Technics SP10 Mk2 or Mk3.  Only the Mk3 would cost anywhere near $10K. The rest are typically cost less than $5K, ready to roll. In a modern plinth, these turntables can be bulletproofed and made to sing.

I’ve owned both these products and am commenting from direct personal experience. When I owned a VPI Classic 3, I purchased a used SDS (for about $750) and noticed a definite improvement in sound quality. I was in an upgrade phase and that set-up was soon the weak link in the system so it was replaced by, in my opinion, the greatly superior Basis 2800 with vacuum, stabilizer base and placed on a Vibraplane. As good as it sounded , the speed was off. 5k for the Basis Synchrowave was not sounding appetizing and with a bit of research I found the Phoenix gear. SDS, new about $1200+/- and inferior, Phoenix gear new, about $600 and superior. For me it was a no brainer and it works perfectly. I’m no engineer or physicist but it seems pretty simple: most LPs were designed to be played at 33 1/3 or 45 rpms. Anything other than that is outside of design spec. The Phoenix gear delivers a clean regenerated power source to the motor and the link between the Roadrunner Tach and PSU insures proper platter speed. Since the minute fluctuations in speed are restrained to a mere .005 rpm window, I would defy anyone or any measuring device to detect any pitch or tonal variations because of speed issues. It seems like there’s a lot of flat earth "thinking" and "reasoning" going on in this discussion. Yes, it possible and useful to use digital and engineering advancements to improve analog systems.
Also, why this constant hijacking of topics? Nobody was asking about DD tts. This was a direct question about two specific products. Start a different discussion if you want to argue the merits of DD vs Belt drive tables, geez :)