Is Direct Drive Really Better?

Bob ... actually you and I are in agreement. The torque is either in the high mass platter, or in the motor, or it is in both. Where it is doesn't matter, what matters is that there is plenty of it.

I'd even go further and say that, I would expect the theory to favor a belt driven table of very high mass, and with a very low torque motor, since a revolving high mass not only has plenty of torque, but because of the low torque motor it should also have a very high degree of speed stability, and noise rejection. The difficulty in the high torque motor approach is guaranteeing that the high torque motor is low noise, and has an extremely stable rotational speed.

But I'd still like to hear a Lenco, Garrard and SP10, and I'd be happy to buy whatever sounded best to me, regardless of my theoretical preconceptions.

My experience has been that solo piano is the torture test for turntable speed stability, so a dose of Beethoven piano sonatas should be all that's required to find the best turntable.

Lloyd Walker tells an amusing story that some of you may have heard... he was demonstrating his Proscenium turntable at a show a few years back when some attendees came in to talk with him about why he didn't use a high torque direct drive design for his table.

Their argument was that only such a design could maintain the pitch stability and drive that music required and that any belt driven turntable (such as the Walker Audio design he was demonstrating) was fundamentally flawed in design.

Lloyd was playing a piano recording at the time (certainly a good test of pitch stability). So, rather than spend a lot of time arguing, he pulled out a pair of scissors and CUT THE DRIVE BELT.

The record continued to play with no discernable change in pitch for at least 20 seconds.

And thus ended the debate.

NB: I own a Walker, so I've got a bias. But I've done the belt cutting routine here just to test Lloyd's story. Amazing what a virtually frictionless high mass (80+ lbs) platter design can accomplish with an extremely low torque motor. (Agree with you on this Seandtaylor99.)
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Hmmm....lots of misunderstandings here. First, to 4yanx and high-end designers. I don't mean high-end turntable designers, but designers of other equipment for which they want the best source they can find in order to demonstrate their wares to best effect. Of course a high-end turntable manufacturer won't be interested unless they use titanium nitrate and high-pressure ceramics developed for NASA to justify high price-tags, as you say. But when the high-end designers, of amps, preamps, speakers and distributors of the same start to use Lencos, Garrards, or other large idler-drives, because they don't sell turntables and don't give a rat's ass what they use as a source, so long as it makes their products sound as good as they can get them to sound, then people will sit up and take notice. This, unfortunately, is the situation, and so I'm opening a new "front". My concern is strictly with the truth, or more accurately, empirical reality. By your own honorable admission - and caveats about getting it set up right notwithstanding (this applies to all components, n'est-ce pas?) - the rebuilt Lencos beat belt-drives at several times their price, and I wonder if you have, in fact, ever heard a belt-drive, at any price, which could even match or beat a properly restored and implemented Lenco in a fair comparison?

Then there is your message here - "The best of our efforts will compete with turntables costing many times more, and we have friends that can attest to this fact. In some ways, they sound better, especially in the lower end and in that indefinable “pleasure” factor. I am neither an engineer nor a psychologist so I will not try to explain the “boogie factor” these tables seem to have." The fact that you can hear this, and it is repeatable from Lenco to Lenco despite differences in plinth materials, design and weight, points to something in the Lenco proper which accounts for this: it is superior speed stability, which in its turn underlines lack of same in belt-drives. It is, being audible, an empirical fact, and being audible there is a physical reason for it, no need for psychology beyond the human ear's EXTREME sensitivity to pitch (speed stability). It has speed stability which is superior to that of the belt-drives you have heard or compared it to. The rest, high frequencies and such-like, can be tuned by implementation, materials, tonearm/cartridge. And, since this "indefinable pleasure factor" is in fact beautiful music-making, then I submit that, this being THE most critical factor in building a successful stereo system and the whole reason we are in this game (not to reproduce boring and unpleasurable music), the Lenco and the idler-wheel drives it represents are quite simply superior to belt-drives, period. It's not about trumpeting the success of this design and "you have the wrong one", it's about deciding which is the best system. How many audiophiles buy one turntable and stay there? Yes, they are currently happy with their given belt-drive, but they will, down the road, spend likely several thousand dollars on another belt-drive, which is inferior to an idler-wheel drive, especially at music-making. If a large company with the resources decides to get into the game and start to produce reasonably-priced idler-wheel drives, we will ALL benefit. In the meantime, we can either get into a restoration DIY project, or get it done, still for far less than the high-end belt-drives which are their "competition".

And while it is true that Garrards 301s/401s and Thorens TD-124s have always had a following, my own thread was never about Lencos, it was using the Lencos which could be had cheaply, as bait to get the world to participate in testing out my claim that idler-wheel drive was a significantly better system than belt-drive and had been unfairly assassinated by a concerted effort of the press and industry (reminds me of digital). I being I think the first, and if not then definitely the most vocal and activist, to step forward and make the unequivocal claim this is so (and for which I get roundly criticized in the current politically-correct "no system is better than another" Western climate, but the battle is what makes it worthwhile ;-)) and challenging the world to a showdown to prove or disprove it (check out my first colossal flop attempt, flop), after which I devised the crafty Home Despot tactic. This is my contribution to the evolution of audio, not simply the discovery of the Lenco (important but not that important by itself without the attendant examination of the logical implications). I discovered the Lenco, actually, because I could not find the Garrards 301/401 I was in fact looking for after tripping over a Garrard SP-25 at a flea-market in Helsinki (I had never even heard of an idler-wheel drive at that point, before the internet), tweaking it, and finding it significantly better than either my Maplenoll (still considered one of the Great Belt-Drives) or Audiomeca turntables in all the most important ways (amazing even at detail)!

Hi Sean: let me use another word, as by "torque" I was thinking, indeed, in automotive terms, in terms of "applied" force, in the sense of an active force, such as a motor. The torque, as in stored energy/moment of inertia, is not sufficient to combat stylus force drag, it takes an active motor force to push the platter through the dramatically-cut grooves and the variable stylus force drag they cause: it will still slow, the belt stretch, and then contract, albeit more slowly as it has to drag so much mass, and the motors used in belt-drives are insufficient to push the LP through and keep the speed rock-steady. In the case of an idler-wheel drive, the motor is powerful, spins at high rpms which by itself tends to smooth out speed imperfections, and it is securely coupled to the platter/flywheel by the rubber wheel, which does not slip, stretch or contract, and which in its turn regulates the motor, making its rotation more perfect. These three elements - powerful high-rpm motor, grippy wheel, flywheel-platter (especially in the Lenco) - create a closed system which utterly ignores stylus force drag, or the cartridge and arm action. The belt-drive/high-mass/high moment of inertia is not a closed system, the stylus force drag will affect the speed to a certain extent, and the proof of this is in the listening. I had a Maplenolll Ariadne with 40-pound lead/graphite platter (the prototype for the Walker Proscenium), and despite the 40-pound platter, it could not equal the Lenco for PRaT, dynamics or even detail and focus/clarity, and this was in the old days before the Lenco plinth and design underwent all sorts of evolutionary steps forward, resulting in a LARGE improvement in overall sound quality over the old early days. Since, I have not yet heard the belt-drive which can even come close to a giant Direct-Coupled Lenco (which maximizes the plinth's noise damping properties and provides for even more stable speed), and can one say that a VPI TNT does not even come close to a Clearaudio Master Reference? Even if this is so, then the Lenco does too and it will be an interesting comparison when finally I get the chance to do it, or someone else. Again, the proof is in the listening, keep your ears open for idler-drives at your local audio shows! I know they are currently fashionable at European audio shows.

Hi Jack, the Thorens is actually a quasi-idler-wheel drive, as the idler-wheel drives a flywheel, which is linked to the platter/main bearing by a belt, so it's back to square one. Given this fact, I expect the restored Lenco to sound quite a bit better. But, the Thorens has a heavier platter, and a high-speed high-torque motor, which belt-drives do not, so the results should be extremely pleasing nevertheless. I am actually currently working on a perfect TD-124 MKI which I will sell on after my experiments, and it has the iron platter. It does indeed attract MCs (MMs no effect) with their more powerful magnets, but the way around this is by use of a glass platter to raise the record at a great enough distance to eliminate this effect, which I have. Anyway, I will build it into a similar plinth to the one developed for the Lenco, high-mass and inert, and report on the experiment on the Home Despot thread (you can get immediately to the last page by clicking on the double arrows at the end of the page numbers). And btw, the Lenco properly implemented (not so difficult, but time-consuming) is in fact quieter than any high-end belt-drive against which it has been pitted so far, the latest local convert commenting that his Lenco is quieter than his Rega P9 with RB-1000 tonearm (which sonically is not even close to being in the same league, in any respect whatsoever), which currently gathers dust. In fact, two things leap out in any demonstration I have participated in so far, ahead of the bass and astonishing lively dynamics: they are all astonished at the extreme quietness/blackness, and they can actually hear the incredible speed stability, not as a result of clarity or detail or what-not, but as actual clearly audible and striking speed stability! Now THAT's speed stability.

I think I made this point once before. If the reason the Lencos sound better is superior speed stability, then CD should have kicked vinyl's butt long ago. I would look elsewhere for the reason you prefer the sound of idler wheels.

Agree with the viewpoint that, in principle (all other things being equal, which they probably won't be in reality), there should be no difference between torque stored as inertia in a high mass platter, and torque as applied by the motor -- at least in the moment of initial transient attack. But the dynamics of how the platter recovers lost speed in preparation for the next transient event, or during sustained peaks, may well be different, and maybe could favor the lower-mass/higher-torque model. (And/or also the model of active speed sense-and-control?) Anyway, there are clear advantages of price and ease of placement in not having to get a TT with a platter that's half your body weight. A lighter platter also eases the job requirement of the main bearing. A degree of flywheel effect is certainly desirable in any TT design, but to me there's something dissatisfying about the idea of always resorting to supermassive platters.

I'm not sure I can entirely agree with Johnnantais on a few other things, but he probably knows more about it than me. Still, I can't reconcile the blanket assertion that a motor turning at 1,500 RPM is intrinsically better than a motor turning at 33 1/3 RPM -- that high rpm "by itself" tends to "smooth out" speed imperfections. If we assume the same level (amplitude) of vibrational contamination for the sake of argument, the only difference, it seems to me, will be in the frequency and its harmonics, which will also alter the spectrum of intermodulation products. That will change the sound, but I don't know which one is better, or what might constitute the "ideal" RPM or frequency to superimpose upon the music signal (none would be nice). But I doubt it's as simple as saying "higher is better", especially when only one fundamental falls within the audioband (1,500 RPM = 25Hz, while 33 1/3 RPM is only about 1/2Hz). I'm not exactly sure if all this stuff is pertinent to the topic at hand though, maybe an engineer or physicist could elaborate further.

If we stipulate (correctly, I hope) that high torque is what pushes the platter through dynamic passages, then as far as I know, in electric motors lower RPM = higher torque (larger motor diameter does too, which DD's also generally have). I have zero experience with the big idler-drivers mentioned, so I'm guessing that for their motors to be both high-speed and high-torque, they must also be relatively large and powerful (higher amp). If so, wouldn't that increase the amplitude of vibrations vs. a lower-speed, lower-amp motor with equivalent torque? Obviously there will be a lot of other variables regarding how any two motors in question are made, but I wonder in principle.

However, it is undeniably true that the faster you spin anything that's not in perfect balance, the more violence will be imparted by its shaking. Can a motor be perfectly balanced? If so, I guess we wouldn't need to have this discussion. So, adding it up, I can't buy the notion that higher motor RPM's are somehow "better" for TT performance. I've always assumed one of the strengths of DD was the low-RPM motor: high-torque, low amplitude of vibration, low frequency of vibration. Somebody please point out the error of my thinking if I'm wrong. Absent the RPM argument, I haven't yet detected the theoretical case for why idler-wheel drive should be intrinsically superior to direct-drive. That it may prove subjectively superior among certain 'tables auditioned by certain listeners is another question.

Maybe I'm way off base somewhere here, but speed performance is measureable -- you don't have to depend solely on subjective listening impressions to find out about this particular factor. Does anyone know that idler-drive tables can have better wow & flutter numbers under dynamic playing conditions than a good quartz/PLL controlled DD? Are there any constraints that prevent a DD motor from being made just as powerful as for an idler-drive, if that's what one wanted? (Magnetic interference with the cartridge, perhaps? The platter's shielding ability may be limited, but I don't know -- I thought the Rockport DD was supposed to be terrifically powerful and nearly impossible to deviate the speed of. If you pay enough, you can get a high-torque/high-mass DD table, with the electronic control to harness both.)

To me, DD does seem to have several intrinsic theoretical advantages. One is that the motive force is applied without physical contact of the platter. If you use a belt or a wheel to transmit force to the platter, it must result in some added degree of motional friction, which must produce a characteristic resonance, much like road noise in tires (okay, so it's probably more like urethane skate wheels on polished marble tile, but the principle still applies -- it's still not silent).

Another is the fact that there's only one bearing, the ubiquitous main bearing. In any design with a separately housed motor, that motor must have its own bearings in addition to the necessary main platter bearing. Then there's shafts and pulleys or wheels -- they won't be perfectly concentric. DD does away with powered driveshafts, pulleys, and/or wheels.

I tend to think simpler is better (simpler, but not too simple! ;^) A TT doesn't get any simpler, mechanically speaking, than a DD: the plinth is the stator, and the platter is the rotor. In any other arrangement, the separate motor can and will move in relation to the platter, which causes variation in platter speed. In a DD the motor can't move relative to the platter, since the platter is itself one half of the motor.

Another thing: I don't know if this absolutely has to be the case, but as far as I know only DD's incorporate electronic sensing and control of platter speed directly, rather than control of motor speed (but typically without sensing, I believe) with a somewhat flexible linkage in between it and the platter. I know which arrangement seems like it would be better to me, but I'm open to arguments. Again, though, the results can be measured.

Along those same lines, there's the issue of how correct speed is established in the first place. With a PLL sensing system in place, it's easy to add calibration to a quartz crystal reference, a very much higher and more constant frequency than (and totally independent of variations in) the AC powerline. Who wouldn't want that if you can have it? And again, the results are measurable.

I've often seen an argument against PLL-controlled DD's that usually goes like this: They are constantly "hunting and pecking" for the correct speed, but never settle on it. I have never understood this. Any electric motor operates in what is termed a "kick and coast" fashion, dependent on the number of poles. More poles would seem to be obviously better than fewer poles, but I don't know that the number of poles possible is in any way linked to or limited by drive method. Anyway, it seems to me it's primarily this kick and coast phenomenon, dynamic stylus drag aside, that's primarily responsible for any TT not constantly rotating at exactly the correct speed, no matter how it's driven. Why this is blamed on implementing a PLL is something I want to know.

Another thing I want to know is why DD is often portrayed as constituting a "rigid coupling" between the motor and the platter (never mind that this doesn't make any semantic sense, since in a DD the platter is in fact part of the motor). At times I almost get the feeling that some audiophiles who haven't owned a DD visualize it as simply consisting of a belt-drive type motor -- meaning a self-contained unit with a housing and a protruding driveshaft -- with the platter stuck on the end of the shaft instead of having a pulley and belt in between. (If that describes anybody reading this, go to the website Viridian linked above and look at the platter-off pics of the SP-10.) Anyway, "rigid coupling" seems to imply that the platter can't "slip", which of course is 180 degrees opposite of the truth -- any DJ knows that only in a DD can the platter be freely spun manually when not under power, or manually deviated with precision from constant speed when under power, from which it will rebound when released. ("Rigid coupling" also implies vibrational transfer, which again to me is a conception misappropriated from the paradigm of separately-housed, self-contained motors physically linked to platters and plinths by compliant couplings.)

As I understand it, in typical audiophile belt-drivers, the elasticity of the belt, combined with the inertia of the massive platter, is supposed to mitigate the kick'n'coast speed variation from the motor. Of course this can't simply be "gotten rid of" -- the elasticity and inertia combine to spread its effects out in time, reducing the amplitude peaks, effectively averaging the variation in speed. Well, platters in DD's also have mass. The "slippage" and subsequent rebound that I described when a drag or an energy input is applied, isn't that functionally equivalent to belt elasticity? It seems to me that in a correctly designed DD, the PLL sense-and-control system, combined with the platter inertia and the natural ability of the platter to smoothly and infinitely vary from constant speed and then rebound without introducing mechanical friction, can constitute exactly the same kind of "averaging" mechanism that smoothes the kick and coast impulses in a belt-driver. The difference is you don't need a supermassive platter or the attendent pitfalls of a belt/pulley/separate-motor system to do it when you've got active speed control working for you.

I know many audiophiles regard the notion of any "servo" or "feedback" type of operation as something they're allergic to, whether it's negative feedback in amplifiers or servo control of subwoofers. As the saying goes, you can't correct something that's already happened. Same for many active vs. passive questions (though not always). I also know many engineers would argue with this attitude and say it's not that simple or universal a truth, that there can be well-implemented applications for feedback-type mechanisms that don't harm sonics in unintended ways.

I can't comment on all that stuff, or its applicability to DD TT design, with any authority (though I don't recall anybody saying that adding an outboard speed controller to their belt-drive TT made it sound worse). Yeah, I own a DD [KAB-modded SL-1200], but like I've said before, I lack the comparitive expeience to make pronouncements about relative superiority. But I also note, with no real satisfaction, that probably no audiophile, no matter how experienced, has ever had the opportunity to compare two turntables whose only difference was method of drive. As we all know, there's a host of other factors which affect TT sonics besides drive type. I also acknowledge that measurements, such as I touted above, often don't tell the whole story sonically speaking (which simply means we need other, better measurements to correlate with what we hear).

More important though are, as I see it, two questions: The one Drubin asks, i.e., do any of the DD's available in the moderate price range (current or restored) warrant consideration over the entry-level and next-tier belt-drive audiophile standbys (none of which are terribly massive due to their reasonable cost)? And the one Macrojack wants to know: Is it time for high end TT makers and audiophiles alike to reconsider the relative merits of the DD option -- could it be exploited to make even better tables than are generally available right now (and if so, at an attainable cost)? I admit I don't know the answer to the first, but feel the second has got to be a yes if at all possible.