Is Direct Drive Really Better?


I've been reading and hearing more and more about the superiority of direct drive because it drives the platter rather than dragging it along by belt. It actually makes some sense if you think about cars. Belt drives rely on momentum from a heavy platter to cruise through tight spots. Direct drive actually powers the platter. Opinions?
macrojack
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MJ and V: Obviously we can't achieve a correct 1:1 correspondence, or probably even seek one realistically speaking. (Although if that were the goal, then you could make the argument that going with a Technics SP which used the same motor/controller as a Matsushita disk-cutter would be a reasonable strategy. However, lacquers aren't the same as vinyl, cutter-heads aren't the same as cartridges, and of course inscribing a groove isn't the same as following one.) The real point may be that, even were we able to achieve "perfect" playback with zero speed distortion (which we can't), if the record weren't cut the same way, you'd still wind up with speed distortion. Boiled down: You'll always have speed distortion. But we already knew that.

As to Viridian's observation, if our theoretical turntable suffers less dynamic drag on transients than the cutting lathe (maybe not as unreasonable an assumption as it might seem, given the presumably much greater frictional resistance encountered by a cutting-head in inscribing the groove as opposed to a stylus merely reading it), then pitches will go slightly sharp on transients. If the turntable suffers more dynamic drag than the lathe on the other hand, then transient pitches will go slightly flat. All in all though, I don't think it's completely unreasonable to speculate that these speed distortions at the mastering and playback ends might indeed have some rough natural correspondence which tends to mitigate the problem more than exacerbate it.
Expounding a bit: Viridian, your last question I think may really concern phase. You might be thinking of "flanging" as an analogy, or the way loudspeakers behave regarding crossovers and multiple drivers or reflective room surfaces. If so, that would not apply to this situation, it seems to me -- that sort of reinforcement/cancellation phenomana requires mixing of more than one sound source, which I think the encode/decode of vinyl playback doesn't qualify as. You are right that pitches are affected, and the resulting pitch distortions will derive from addition and subtraction, but I don't believe there is any constructive/destructive reinforcement going on as I understand the concept. For instance, to "flange" as they originally did in the recording studio, you need two reels of tape both with the same signal recorded on them, played back in synchrony, which is then modified by applying friction via the engineer's hands to the reels' flanges. But if you recorded one reel of tape while altering the pitch by applying drag to the flange, and then played that pitch-altered reel back while doing the same thing again, the "flanging" effect would not be the result, just further pitch distortion.
Macrojack, I built an idler wheel table from a Lenco and I would not consider myself to be a DIY guy (although I am getting better) - it's not that hard if you have the time to do it. You cut some plywood and MDF to the same size, cut out the cavities for the guts of the lenco to fit inside it, glue the layers together, bolt the lenco onto the plinth, finish with self-adhering veneer or stain it. The veneer covers a lot of the mistakes. If you use the right arm or turn the thing 90 degrees, you don't need to cut the base plate to set the arm. You clean the motor and the bearing, stick some dampening under the plate, and for $500 you're stunned.

I don't have an opinion about which is better in the drives, but I will say without any reservation that I have enjoyed the hell out of mine. If like me you really get turned on by value, well, this is a real value in audio.

Plus you get to tell people "I built a turntable" and that in and of itself is worth the effort.

Lenco's are on ebay all the time - there are some specific models to buy and some to avoid. I used an L 75. I think the 69 (someone correct me if I am wrong) is also good - these have aluminum idler wheels rather than plastic.

So, if you really are curious, I am your role model. If I can do it, you can do it.