VPI HW-19 Upgrade question SAMA or SDS?

Buconero117... the SDS IS and improvement not because of the trick that you can change the pitch, but because the SDS provides a constant and reliable electric source for the motors. The sound IS improved with its addition because the turntable revolves at a constant speed with far less short term variation. ..and that is why belt drive turntables that use string instead of elastic belts and the reason that the Lenco and VPI rim drives et al is so far superior to its belt drive counterparts. Short term speed variations are very greatly reduced. On another note... VPI has a plastic stobe that I got with my tonearm...I presume you can purchase it through VPI and regular purveyors of such items. Go to Home Depot and get a fluorescent night light...mine is an Aperitac model 73068. The cost was about 4.99 on sale. Use an extension cord for convenience, look down at the correct band of the strobe turning on your table and adjust the SDS so that the dots seem to stand still. If the dots are moving clockwise, push the downward arrow on the SDS which slows down the table, and v/v,,,,, you're in business.

Sorry Buconero...I misread your question...I thought it was for a turntable.

Stringreen, I always welcome spirited discourse about the finer points of music making and playback. My comments are not intended to offend in any way. Having said that, I think I can prove my point to you:

It is true that if a turntable's speed accuracy is off by a very small amount, one may not necessarily be aware of a problem during playback, unless one has perfect pitch. My contention is that the performance may simply not be experienced as originally intended by the performers, because the music may now be just a bit under or over the intended tempo. Additionally, the pitch distortion (and it is just that) will void the emotional effect of the chosen pitch center. This, I hope we can agree, is a problem.
We agree that orchestras and/or their conductors choose the "A" that they tune to, and that this choice has an emotional effect. Here are some numbers that I think prove my point, as it relates to vinyl playback:

-A 3.3% deviation in rotational speed of a turntable's platter results in a change of one half step in pitch.

-The difference between "A" 440 and "A" 441 represents a mere .23% change in pitch.

-If you do the math you will see that a mere .13% deviation from perfect rotational speed results in the aforementioned .23% change in pitch. A not unlikely scenario with many turntables. Amazing, when you consider that the "broadcast standard" has been .3% speed accuracy.

We agree that the difference between "A" 440 and "A" 441 is significant. When you consider that the error is oftentimes much greater, you can see the importance of it all. I am sure that as a performer yourself, you have oftentimes experienced playing situations where the pitch center is off by an even smaller amount than the statistical difference between "A" 440 and "A" 441; where the difference is simply an almost subliminal feeling that the pitch center is just "leaning" one way or the other. In analog playback, a change in pitch also means a change in tempo (unlike with digital). However subtle that change may be, it will most certainly create a different emtional effect from what the performers intended. Again, as a performer, I am sure you and your colleagues have often remarked during a rehearsal or performance that the chosen tempo is the perfect tempo (or the wrong tempo) for a particular piece. That chosen tempo may be, in actuality, only a fraction of the difference between two adjacent markings on a metronome.

Clearly, vinyl playback can be enjoyed, and be quite good, in spite of small deviations from perfect platter speed. But is it more accurate, more enjoyable, and potentially more exciting when the speed is right? Without question. When you consider how much effort we put into getting other aspects of playback right, or as right as possible, why not do what we can to get the speed accuracy correct?

Thank you, thank you, thank you all for the great information.

I've sure learned a lot from this thread.

Frogman... My point was that short term speed deviations can be/are very distracting/annoying, and that long term speed difference aren't important. Going back to the original posts that said things like lubrication, dynamic contrast friction, etc. are critical... no. I agree that if the table doesn't spin at the exact speed it is distortion, and naturally our goal is to eliminate/mollify distortions, yet, it is not necessary to constantly adjust the speed for acceptable/pleasurable vinyl reproduction. Regas typically run fast, and yet, they are valued and praised with justification.