Turntable speed accuracy

What Viridian said and Halcro hinted at. More important is stable speed regardless of groove modulation, as opposed to bang on 33.33 rpm. If a table can stay at 32 rpm whilst tracking any and all passages, then it could probably be adjusted to run stably at 33 rpm, so absolute speed is less of an issue, IMO. I read a very insightful piece somewhere on the internet last week which pointed out that the turntable provides fully "half" the music, as its speed past the stylus provides the horizontal axis of the complex sine waves that represent music, if it were graphically displayed for example with an oscilloscope. The cartridge can only give us the other half, the vertical or amplitude direction. All musical timing must come from the tt. Pretty sobering, eh? Well, I knew that, but I had never thought of it that way.

Davide256, everything you write is so obvious and logical, yet wrong as regards points one and two. Point 3 does count for a lot too, I grant you.

People who don't like direct drive generally make the same point you have made re "isolation". Usually such persons do not own and have not owned a direct drive turntable. However, if you examine the workings of the best examples, you will see that the platter is part of the motor. Thus "isolation" is really a function of the quality of the bearing, which is an issue of equal significance for BD turntables as well.

Ct, Altho I am currently a partisan of direct- and idler-drive turntables, I would nevertheless take those data you quoted (0% speed deviation at 5 kg.cm) with a grain of salt. The Technics uses a servo to keep speed stable, but a servo is not perfect in terms of avoiding "micro" changes in speed that it then has to correct for. So "average speed" may indeed not vary, but the devil is in those corrective measures mediated by the servo to keep the speed stable. The jury is out as to whether we can hear that happening. Some claim that they can. BD turntables pose entirely different problems as regards speed stability at the micro level. Some of us can hear that, too. Pick your poison.

kg.cm (kilogram X cm) must be a unit of Work or Energy. Work is defined as Force (F) acting through a distance (s); W = F(s). Kilogram is formally a unit of mass, but by convention we also refer to it as a unit of weight. Weight is mass X acceleration due to gravity (W = m(g)). The analogy to F = ma is obvious. So "weight" is actually an expression of force. That's what they taught me in college. It's a bit confusing, but I think that kg.cm is a unit of Work. (I've just been reading a book about how Einstein interpreted Newton, so I have been thinking about this stuff.)

Since Dertonearm did this to me once, when I erroneously attributed the phrase "one man's meat is another man's poison" to Shakespeare, I will now point out that Shakespeare is the oft-cited source for the quote "love is blind" (from The Merchant of Venice). This is not to say that a Dutch person did not also say it. And at perfect speed so as not to alter pitch.

Dear Ct, Always glad when I can "clarify" something for you, but who can imagine 500 tonearms sitting on one LP? Now that takes some fantasizing. Thanks, Tim, for bringing up that very simple metaphor.

Downunder, if the battery in the Timeline is running low, at some point the laser will abruptly turn off completely, I would think. I think the laser operates like and LED which is like a diode; you need a threshold of energy to activate it. So when you go below that threshold - no light. In any event, I do not think waning battery life would affect its frequency.

I respect the work of Kuzma, Driessen, and Yorke, from a distance. I only say what I say about Lurne' because of my experience with his earliest Audiomeca product. And my opinion should really mean nothing. As I once told you, were I to be in the market for a belt-drive type turntable, the Kuzma Reference, a la chez Nandric, would be my choice.

Davide256, With all due respect, you are wrong. Linn is OK right after the suspension is tuned and for the next week thereafter. AR and SOTA, up to and perhaps not including their very latest TOTL models, are seriously flawed as regards speed stability. My SOTA Star Sapphire III was a distortion generator on piano music. Have you ever heard a real piano? Do you really like stretch-y belts and belt creep that much? And AR? A classic, yes. A bargain in its day, yes. But an example of how to build a speed-stable tt? Puh-leeeeeze.

Also and parenthetically, you don't understand the mechanism of a direct-drive turntable. I think I mentioned this to you somewhere above this last post. Do some reading on this subject. The issue in direct-drive is not noise but designing a motor that is free of cogging at slow speed. (The DD motor has to turn at 33 rpm, whereas belt drive and idler drive motors turn much faster. This tends to make them noisier than DD, not quieter, but a little easier to mask the cogging effect.}

But the syntax of your post actually suggests you like direct-drive better than belt drive. (You start with your criticism of direct drive and then begin your discussion of belt drive with the phrase "next best", implying dd is better, which it actually is when done right, IMO.)

Dear Hiho, I am trying to understand your post on SOTA. Do you mean to say that the Cosmos is subject to M Fremer's critique (motor mounted to base/platter on spring suspension, which is also my criticism), or not? Most users seem to like the Cosmos and the Millennium, so I was not sure whether the current owners of SOTA had cured that problem (by re-design) or not. Surely it was a major issue with the Star Sapphire and that design flaw goes all the way back to the AR. (I have owned both for years at a time.) We forgave the AR for it, because the tt was so cheap and otherwise a good performer. I don't know how the Linn Sondek LP12 is built (never owned one), but the same issue is posed for any belt-drive/spring suspension.

"After living with it from '96 till today, I can say that it is not to my liking."
Dear Geoch, After reading the line I have pasted above this one, I would have to say that 15 years of suffering gives you the right to criticize. Now you can get rid of the damn thing. You've given it a fair chance to impress you.

Thanks, Hiho. I am heartened that SOTA fixed that problem. For years with the SOTA Star Sapphire, i thought pitch inaccuracy on piano was normal for LPs. (It replaced a TD125 way back in the early 80s, but I have no recollection of the sound of the TD125.) I have heard from a reliable source that the Spiral Groove tt's are superb as well, attesting to the design skills of Perkins.

For an embarrassingly long period of time I was laboring in my spare time on a complete revision of my Atma-sphere amplifiers. Thus I was not really doing much listening except with a Parasound ss amplifier that did not compel me very much. Two or three days ago, I got my system back up and running with the Atma amps driving the Sound Labs (also with highly modified and very simplified input circuit). By the same token, it was my first extensive audition of my Technics SP10 Mk3 with Reed tonearm. All I can say is "My goodness". Talk about speed and pitch stability and rhythm; that thing is amazing. My wife, who takes only a passing interest in my audio system and in my jazz listening, sat with me for 2 hours, riveted as was I. I have been an audiophile for 35 years but only with DD and idler-drive for maybe two years. I have no plans to go back to bd.

Thanks, Tony, for introducing some science to the foregoing discussion. I know I am going to sound like one of Syntax's "fanboys", but I have been listening to my Technics SP10 Mk3 for the first time in extensive sessions over this past weekend. And I am astounded by the rhythm and drive this table can impart to music on LPs with which I am very familiar. Try "Art Pepper + Eleven", which contains just about every bebop rhythm one can imagine. There were tears in my eyes, literally. Yes, Tony, the Mk3 can bring its 21-lb platter up to speed in one rotation, probably sooner. I have been arguing this stuff on a theoretical basis; now I am a true believer.

Dear Thuchan, Please do not jump, but isn't the answer to your question obvious? If the 3 tt's sound different, then they are introducing different "colorations". Or possibly one is "neutral" and the other two are introducing colorations. No matter how you say it, these colorations amount to distortion in one form or another. I would also say that it does not matter, as long as any of them can make you feel you are at a live event, or even if they make you feel alive. How about the Continuum, which you don't mention?

I am with you in this dilemma, which is why I hate the word "neutral" when used to describe an audio product. It can have any meaning that the user wishes it to have. One meaningful way to use it would be to say that "I have heard this or that LP many times in my own system using a wide variety of turntables, tonearms, and cartridges, and I find that this turntable/tonearm/cartridge seems to add less (or more) to the basic sound on this LP than does that turntable/tonearm/cartridge". Or something like that.

Tony, I don't quite see your "one revolution" hypothesis. The platter once in play never comes to a complete halt. I think the point is that the motor needs to have "enough" torque to keep speed stable. And the definition of "enough torque" is related to inertial mass of the platter and servo design. In bd turntables, the belt/thread/tape is an added factor in the equation. In idlers it's the idler drive system.

Tony, What I meant was that in direct-drive turntables, the motor, the drive system (aka servo), and the platter together form a closed system. So indeed the mass of the platter has everything to do with it. If you don't see what I mean, try removing the platter from a direct-drive turntable. The result will be a pronounced herky-jerky motion as the servo goes searching for its proper load. If you dramatically increase the mass of the platter (yes, "m"), the servo can get similarly screwy, slow to correct for off-speed moments, but it is less easy to see. It is the servo that tells the motor "how much acceleration is enough" to get back to equilibrium.

None of this is to contradict what you say about LPs with off-center holes (i.e., most of them). That's a big, important, and separate issue.

Dear Tony, Cogging is indeed a problem with motors, but what I described would not be strictly due to cogging. Mostly it is due to the servo hunting when its feedback loop is screwed up by the lack of a platter mass or in the other extreme, too much platter mass. Cogging will always be there and is an inherent property of the motor; some are less prone to cogging than others.

Gosh, what is left to say or think after that?
I agree that direct-drive turntables can be highly "colored", in a bad way. I also completely disagree; speed stability is the sine qua non of a turntable, no matter the drive system. "Sound quality", if by that term you mean the degree to which the sound emanating from the speakers can be made to emulate "real life" does depend very much upon speed stability. From that comes rhythm. From rhythm comes verisimilitude, in part.

Sure, a tt with excellent speed stability can sound bad for other reasons.

Why is a battery power supply, per se, likely to be superior to all other approaches to power supply?

It's actually 1.80018... I think it's a repeating number. Let's hope Mr. Sutherland set his timing thus. Otherwise, the instrument is off by .00018 sec per revolution. Apparently this much error would drive some of us crazy or to a new turntable.

It seems like none of us read each other's posts, except Raul and DT, so that they can reach immediate disagreement. A century ago an American writer named Ambrose Bierce defined "conversation" as a social interaction wherein I wait for you to finish talking so I can say what I want to say. In any case re turntables, DT is right. The first job of a tt is to get speed right. Raul used to argue that a phono stage that does not do riaa within 0.1 db is fatally flawed. You can't have it both ways, Raul.

Bearing lube for dd turntables is yet another controversial subject. Fortunately, the rotation is so slow and relatively low stress that almost anything will do to prevent bearing damage. One guy who restored my L07D insists on only a certain weight of a certain racing motor oil. I am sure it is overkill.

Accuracy or sensitivity of speed monitor device should be proportional to (1) distance of sensor from center of rotate (longer radius is better) and (2) stability of the strobe at 60 hz per second. Ergo in theory the kab strobe (battery powered and not subject to AC line frequency variations) should be superior to timeline (batt power but v short radius) and to allnic (worst, with AC line power AND short radius). Admittedly, the kab is least convenient.

My mistake, Thuchan. So therefore the allnic and the timekeeper would be about the same. I thought I had read elsewhere that the allnic light needs to be plugged in to AC.

If you take a look at one of the old brochures for the Denon DP80 (I think), they present an actual plot of instantaneous speed v time. The DP80 is not perfect in this graph, but Denon claim it was superior to the un-named competition. This is really just to say that the old guys understood and were able to graph this phenomenon.

Dear Henry, What about listening? When you set the table up using the KAB vs using the Timeline, were there any audible differences? If the KAB was that far off, on the slow side, you ought to have heard it in the form of pitch distortion and/or rhythm distortion. One would have to think that one of your two devices might indeed be defective. Either that or neither is quite accurate.

I had an interesting experience just a few days ago. When I originally set up my Lenco, I had it running at 33 rpm per the KAB strobe, with AC direct from one of my dedicated house lines. (You can adjust speed on a Lenco by moving the idler wheel up or down a tapered shaft driven by the motor.) Then I inserted my Walker Audio motor controller and had the Lenco set at exactly 33 with the Walker. Then some months later, I removed the Walker and was running direct from the wall socket again, but I had not re-checked the speed when I went back to house AC. The other day, I had an audiophile friend here listening with me to the Lenco, and he remarked that it sounded "slow"; he perceived a pitch problem. So we took out the KAB strobe again, and indeed, with the stylus in the groove, the Lenco was slow. I was embarrassed that I had not picked up on this problem. However, after he left, I realized that I had been bothered by the musical timing with the Lenco. Tempo seemed consistently "slow", but I heard no real problem with pitch. I had even wondered why Ella Fitzgerald had chosen a slow tempo for a Harold Arlen tune that I considered to be a good swing. The point is that what he perceived as a pitch problem was perceived by me as a timing problem. Obviously, tt speed affects both. I subsequently re-inserted the Walker and now all is well. The brain is a funny organ. He cannot sing to save his life, and I am a long time amateur jazz singer. You would think that I would have at least as good a sense of pitch as he does.

Dear Raul, I did not mean to imply that I KNOW that the Timeline is miscalibrated. I was just musing after Timeltel's correction of Catastrofe's calculation that in truth the time for one revolution, if the speed is 33.333.... would be slightly more than 1.8 sec. It might be 1.800180018.... I would assume that Mr. Sutherland knows that, too. All he had to do was to build a circuit that can divide 60 by 33.33333... and then trigger a laser according to the result, in seconds. And apparently he warned end users that they might not want to know what the Timeline can tell them. It's like going to the doctor for that pain in your .....wherever.

Dear Henry, I would agree that if the Timeline and the Victor TT101 are in perfect sync, it is likely that the Timeline is bang "on". But in general it is not valid to calibrate an instrument against the thing you are trying to measure with it.

I am going to borrow the Timeline tomorrow.

But not all my turntables are in service, so it will take a while to arrive at a full report.

Sksos1. In a word, no. I do not own a TT Weights turntable. I own a tweaked Lenco in a slate plinth, a Denon DP80 in a slate plinth, a Technics SP10 Mk3 in a slate and wood plinth, and a Kenwood L07D. I should sell two of them, but I cannot pick which ones. They each seem irreplaceable. About 4 years ago, I went from a very good belt-drive tt ($5000 class) to the Lenco and then to direct-drive, and I have no second thoughts. But I do confess that vintage tt's appeal to the collector instinct in me.

Since others here have also indicated that their turntables of many various types have "failed" the Timeline test, perhaps it is unwise or unfair to keep harping on the one brand that you found to be faulty by that sole criterion.

Should have read Tony's post before writing the above post. I think the amount of error and the type of error Tony describes should be perfectly acceptable. It is a linear error; in other words it would be the result of the platter spinning a teeny bit too fast at some constant rate. That kind of error should be adjustable back to dead on accurate, and if it's not, it nevertheless would be inconsequential. I thought we all agreed that the concern is for transient or instantaneous errors related to variations in stylus drag. Such errors would in theory go either way, too fast or too slow. So the Timeline light might move back and forth in either direction from neutral.

Dear Tony,
You wrote, "the laser mark should drift slowly in one direction over the 30 minutes. That is the cumulative error" Yes and no. Yes, the drift of the Timeline laser over time is the cumulative error, but no (IMO), the laser may not drift only in one direction, as I wrote above. It could conceivably drift in either or both directions over a 30-min time frame. Therefore using the cumulative error over time as a standard might be misleading. You've got to sit there and watch that laser every single revolution.... (You are getting sleepy.... Your eyelids are growing heavy... You are in my power... You will do whatever I say...)

I vote a moratorium on these endless circular arguments over the merits and demerits of this or that drive mechanism. Lets just see how various ones of them work according to Timeline. But in general, a good direct-drive motor WiLL have more torque than a good belt-drive motor. However I will not claim that this per se makes one better or worse than the other.

I am also wracking my brain to think whether I know anyone who can test the Timeline out of context (meaning not by using a turntable). Some sort of light-sensitive timer is needed.

I've got the Timeline in house.
On the Lenco, with AC supplied through the Walker Motor Controller, speed set by the KAB with an LP in play, and listening tests suggesting that rhythm and pitch are like real life, the Timeline says my Lenco is a touch fast. I will need another day to determine whether it is "regularly" fast (the error increases in a linear fashion with each revolution) or "irregularly" fast (the error is haphazard in magnitude per revolution). The first kind of error can be "fixed", if I care to do so. The second kind indicates that the Lenco is affected by stylus drag. Not so easy to fix. One red herring: the LP is sitting on a Boston Audio Mat1, which is kind of slippery; the LP itself could be sliding due to stylus drag. I hate when that happens. I hate record weights.

Actually, since the Timeline is sitting on the spindle, and cannot fit completely over the spindle on a Lenco, which has a "fat"spindle, slippage of the LP would have no direct effect on the Timeline, in my particular report above. The Timeline is nowhere near to contacting the actual LP surface; it is kind of perched about 1 cm above it, which is as far down as it can go on the Lenco spindle.

Ct, Please say why you think there is anything of value to be learned by running without the Walker MC. I don't see the point, once I were to re-set the speed using the idler wheel adjustment. The Walker has no feedback mechanism; it only regenerates the AC used by the motor and controls motor speed by altering voltage. If anything, the WMC may reduce the torque of the single phase induction motor of the Lenco, because for this type of motor, voltage and torque are interdependent, within a limited range of adjustment.

Dear Swampy, Halcro may be trying to tell you that we have covered the territory of your query, and "we" tend to agree with you, I think. I certainly do.

Hiho, There is much ignorance among us as to how the servo system of this or that direct-drive turntable actually works. From my casual observation, they are not all the same, by any means. But from a Newtonian point of view, max torque is only ever attained at the moment of start-up, when the platter is completely at rest and then must undergo a change of inertia to being in motion at 33.333... rpm. So, the huge torque of an SP10 Mk3 is what gets its 22-lb platter up to speed in 0.25 seconds (or something like that, according to the Mk3 owner's manual). Once the platter (any platter) is in motion at its set speed, it does not take much torque to keep it there, except that which is needed to counter-act stylus drag. Here is where the design and implementation of the servo mechanism is different for different vintage types. For example, I am not sure I understand exactly how the L07D system works, but it appears that the full torque of the motor is only invoked when or if there is a major loss of speed for whatever reason. (I think the service manual says more than a +/-3% speed deficit.) Otherwise, the drive system doles out torque in small increments, and I think this is done to minimize the audibility of tiny corrections that need to be made to maintain exact speed. The engineers of the 1970s and 80s were well aware of all of these issues that we are now still obsessing over. The L07D may turn out to be my all-time fave, and it's not the highest torque in town.

And, lest we forget, among designers of both belt- and direct-drive turntables there seems to be a divide around weak motor/huge platter vs strong motor/light(er) platter. There are logical arguments either way. So, I would not be so bold as to make any declarative statements.

Dear Dover, The statement you "struggle" with is really most applicable to belt-drive turntables, where the two paradigms are most obvious. Compare the Walker Proscenium or any Nottingham (weak motor/big platter school) to an SME or an Avid turntable (strong motor/relatively lightweight platter). And there are many more examples on either side that I am not thinking of at the moment. In direct-drive, we have the SP10 Mk3 (hi-torque) vs the Kenwood L07D (relatively lo-torque but no slouch for torque), but the contrast is not nearly so great since the Mk3 has a heavier platter than does the Kenwood, but the Kenwood is up there in weight compared to most others, e.g. Denon, Victor, Sony. Too bad Travis is preoccupied with moving from Tokyo to HK; he could quote more chapter and verse than I vis vintage dd's. And Kenwood and hi-end Pioneer (read "Exclusive") used coreless motors which tend to be less torque-y because hi-torque versions get too hot, according to my reading. With no core iron, the heat associated with hi-torque is not so well dissipated.

Dear Nikola, Without saying unkind words about his products that have been sold in the US, I just cannot put Lurne' in the pantheon of great tt designers. Perhaps he marketed some tt's exclusively in Europe that were exceptional.

For the past 20 years, the fashion has heavily favored belt-drive, thanks to Ivor Tiefenbrun and the Linn LP12 and complicit audio reviewers. Only a brave man would have introduced a new direct-drive turntable in the 90s and early 21st century, after the technology had been denigrated for so many years. Plus, and we have been over this ad nauseam, it is much more expensive and technologically challenging to build a new sota direct-drive than it is to do a new belt-drive. Now we finally have a few, in the form first of the Rockport Sirius (a real pioneer product, IMO) and then of the GP Monaco, Brinkmanns, NVS, and Teres Certus. But these are all very expensive and therefore rare.

Dover, FWIW, the motor in the SP10 Mk3 is NOT identical to the cutting lathe motor also made by Technics and used by many in the manufacture of LPs. That one has even much more torque than the Mk3 motor. The Mk3 motor and its drive system were explicitly designed for LP playback.

We interrupt this program for one comment on tt speed accuracy: For those of you who have been holding your breath for a report on the speed accuracy of my SP10 Mk3, results are in: Perfect! I am so relieved I am going to sit down now with a stiff cognac, keeping in mind that this is a Sunday morning. I had had such faith in the Mk3 that I had never checked it before, even with my KAB strobe, but you guys have made me question my convictions.

The AC voltage at my wall socket is 121V this morning. I actually feared that this over-voltage (Technics PS says to feed it 110V) would confound the Technics. But the PS has an AC regenerator built into it, so apparently no issues.

I actually re-heated my morning coffee by placing it squarely in line with a laser beam from the Timeline whilst it was rotating on my Mk3 which was playing a Wagnerian opera using an old Decca spherical stylus cartridge that tracks at 4 gm..... Just kidding about the Wagner. I hold with Mark Twain who said, "Wagner is not as bad as it sounds". (Well, I mentioned cognac, did I not?)

But I now understand Henry more fully.

The concept of "belt creep" and what to do about it is not mine intellectually. This phenomenon was first described to me and to anyone else who read it by Mark Kelly. Mark played at designing a bd tt to combat it. The Artemis is a less complex solution compared to Mark's, IIRC. But your SME is well designed, Peter, if it places the motor pulley as close as possible to the platter's edge. Notts recommend this also. That also is a way to maximize the contact between platter and belt. You BD guys should look for posts by Doug Deacon on "tape drive". Doug uses a specific kind of recording tape which he then treats chemically to make one side rough, so it has traction on the platter. Conceptually, this should be better than string, IMO. Reality is sometimes different from concept, however. But Doug claims excellent results with his Galibier turntable.

Use of a capstan, etc, or any strategy that increases the area of contact between the belt and the platter is a good way to combat "belt creep", the bete noir of belt-drive tt's. This is why I am skeptical about 2- and 3-motor arrangements; of necessity, the platter to belt contact area is reduced in both cases, even compared to conventional single-motor arrangements. This is also why I really like the Artemis SA1 turntable, in principle. (Never heard it.) It uses a single motor and a capstan so that the belt (looks like tape) is nearly completely in contact with the circumference of the platter.

Dare I say that a device like the KAB might be superior to the Timeline for detection of very transient deviations in speed? OK. I said it.

Dev,
The Lenco is pretty near infinitely adjustable, as the idler wheel is driven by a tapered shaft that is an extension of the rotor of the motor. So, if the Lenco was off, it simply needed to be adjusted by moving the idler wheel with respect to the variable circumference of the drive shaft. This is how Lenco attains the 3 speeds (33, 45, and 78 rpm). Rather than fiddle with the idler wheel, I made fine adjustments to the speed of my Lenco via my Walker Motor Controller. As to the SP10 MkII, Hiho got it right. Although there is no user accessible speed adjustment, the proper set-up of the outboard power supply WILL result in exact correct platter speed. If the one you tested was not spot-on, then the tt needed some TLC, is all.
Sarcher,
You make a valid point about the fact that if you move the motor pulley close to the platter, the belt will have a smaller area of contact with the drive pulley than when the platter is distant from the pulley. I was merely commenting that both SME and Nottingham recommend proximity of the two. It is not as good a solution as using a capstan, a la the Artemis tt.

As to the question of hum, I am very surprised to read that you have a problem with hum when the motor is close to the platter on whatever turntable. In most cases the motor and its pulley can be placed or is permanently installed at the left rear corner of the plinth such that the cartridge never gets closer than 7 or 8 inches from the motor (half the diameter of an LP plus half the diameter of the label). I don't know of any cartridge that should be THAT sensitive to the EMI or RFI put out by a typical BD motor. The Lenco motor is right under its platter, and I have never ever heard an issue with induced hum. It is said that Grado cartridges are or were unusually hum-sensitive; perhaps you use a Grado. (I have a Grado TLZ and never had a hum problem with it, however.)

And finally, all this chat is still overlooking what I thought was the real issue: speed variation due to stylus drag. None of the above mentioned observations really tell us anything about that. Unless sensitivity to stylus drag is gross, the Timeline may not reveal it. I guess if the speed is "off" with no load, it is unlikely to be stable with a load, but maybe not. One possible benefit of intentional viscous drag or the "eddy current brake" used on the Garrard 301/401 I think would be increased speed stability in the face of stylus drag, a very good way to deal with it.

Dear Uru, I am not the font of all knowledge on this subject, hardly. But what you suggest does seem logical; the speed of a tt may deliberately be set to slightly fast with no load, so that it then achieves perfect speed with the load of stylus drag. But in principle, I would prefer a motor or drive system that is robust enough to maintain proper speed under all conditions, because the load of stylus drag is varying all the time due to the groove modulations and also in relation to the distance of the stylus tip from the spindle. It would therefore be impossible to know in advance and for all LPs "how fast" is fast enough to result in correct speed in the presence of stylus drag. So, IMO, this is where torque, the compliance of the drive system, the speed corrective capacity of the drive electronics, etc, come into play.

Sarcher, What is the evidence that the hum is (or was) due to the motor/cartridge interaction?

Banquo, I have some knowledge but not much skill when it comes to the electronics of either a motor controller (for BD) or a drive system for a DD tt. If I have a problem, I rely upon Bill Thalmann to deal with it, at my expense. But I do have the good fortune to live within 30 min of Bill's shop.

Henry, I've done it both ways with the Lenco and Mk3. The DP80 has no cartridge mounted at the moment, so could not do it with "stylus drag" factor. Likewise, I don't have 3 tonearms on any one tt, so could not repeat that show either.

If the tt is not slowing due to stylus, based on Timeline, then one would also not expect to see it with the KAB, so I am in no position to argue your point that only the Timeline can reveal it. Nor do I doubt you, absent any experience of my own.

Dear Mab, L07D is not in service at this time. I am re-wiring the tonearm.

Dear Dev, Your question was: "don't you think it's strange that a well known source who is selling these replied by saying they are close and not as you did saying it can be set to be spot on?" To that, my answer has to be "yes, I think it is strange". Perhaps the responder did not wish to guarantee that his Lenco would be "spot on" in the presence of stylus drag, but there is no doubt that the speed can be adjusted finely via setting the idler wheel position in relation to the length of the tapered drive shaft. If you take a look at photos of the drive system probably available on Lenco Heaven, you will see in a moment what I am talking about. It might be a pain in the arse but it can be done. Moreover, a generic motor controller like the Walker or the SDS could be used to make up for any slight error above or below exact speed. So, I am with you on that.

Ummm..., Dev, I think you took what I wrote and ran away with it. You can't have it both ways; either a turntable is given to you with the possibility to adjust its speed and therefore correct for any inaccuracy, or not. In the latter case, the turntable had darn well be speed-stable under all conditions, because there is nothing you can do about it. I take it as a virtue that the Lenco mechanism provides an easy way to adjust speed over a very wide range.

By the way, I meant to convey that I was too lazy to do a fine adjustment of the idler wheel, to get my Lenco back to exact speed, so I did it with the Walker motor controller. Since the needed correction was tiny, it was not an issue to do it with the Walker, and I had been meaning to re-insert it in the system in any case, to isolate the Lenco motor so as to block EMI from getting into the AC feeding my preamp.

Then, too, there are two different issues: speed adjustability and stability with no load vs speed stability under the actual condition of playing an LP. That latter property has more to do with torque, compliance in the drive system, platter mass, presence of a servo feedback loop (really only a property of DD turntables), etc. I've been saying this over and over. I guess if you don't like the Lenco, that's cool, but I think you are criticizing it for the wrong reasons. Have you ever heard an LP being played on one? They impart great clarity and drive for a fraction of the cost of other tt's that sound as good (unless you buy a dolled-up version). Isn't that why we are here? I recommend that you listen to a "street version", if possible, before you dismiss the idea.

Henry, You wrote, "well trained ears are our best tools". Did you read my story about listening to my Lenco when it was going too slow, where I heard it as a slowing of tempo and my friend heard it as a flattening of pitch. Two pairs of "well-trained" ears that heard the same music in different ways.

Here is a link: Go back up the thread two or three posts of mine, and you will find it. Anyway, there is no need, because I just summed up the story. The oddity is that he claims to be unable to sing a single note but to have a perfect sense of pitch. OTOH, I sing jazz informally and sometimes formally but sensed the tempo error, not the pitch error.

A lot of good jazz singers sing on the low edge of the note, if you know what I mean. (I refer here to real professionals, not me. If I do it, it is a mistake.) It imparts a blue-sy feel. (Examples might be Betty Carter, Chris Connor, Kurt Elling.) Perhaps that is why I was not hearing the pitch error. Kind of like tuning an orchestra to 438Hz instead of 440Hz.

Dev, As I wrote, I used the Walker because (1) the exact final speed adjustment using only the Lenco idler wheel requires a bit of fiddling. (For example, you have to remove the platter to loosen the adjustment screws, the way I have rebuilt mine, then replace the platter to set the speed, then remove the platter to tighten down the adjustment screws, then replace the platter again, etc.) And, (2) there are some unrelated benefits of using a motor controller; namely it isolates the tt motor from the AC line. Thus any EMI emanating from the motor cannot get back to contaminate AC feeding my phono stage, etc. Is that clear enough? Nothing mysterious.

Also, I already own the Walker, so why not use it? The Walker is useless with any of my other tt's, which are all direct-drive.

One more thing. I realized whilst taking my evening stroll that I had misrepresented the Lenco. I alone have set up mine so that the speed adjustment is so tedious. On a stock Lenco, there is an external lever that allows you to select 16, 33, 45m or 78 rpm without ever removing the platter, once you have manually set the idler wheel in relation to the motor shaft. So, possibly the guy who told you that the speed was not spot on was using a stock Lenco L75 and was not hip to the fact that a small speed error can be easily corrected with a little DIY effort. I believed that firmly and permanently anchoring the distal end of the idler arm was preferable to using the external adjustment mechanism, wherein the pivot of the idler arm rides on a rail across the motor drive shaft, as you select speed.