Idlers vs Direct Drive vs Belt Drive

[tima]

Tima, thanks for this. So the wow of .01 and flutter of .02 specifications of both the SME30/12 and TechDas AF1 are at inaudible levels. That is good to know. You can do a search of each turntable and reviews at HiFi + magazine for the test results. I don't think they go into methodology in the reviews, but perhaps more digging on the magazine website could lead you to it.

I presume David's intention with this thread was to discuss sonic differences between these drive types in general terms and the methods particular designers use to correct for speed errors. I wish there was more information out there from manufacturers about their design choices. Even if we reach a point where we can agree that the Monaco has excellent speed accuracy and consistency, it is how that speed is maintained that in part contributes to the sound of the turntable. And then there are all of the other design choices like mass, isolation, suspension, materials etc that give the Monaco its unique sound. If it were just speed accuracy that mattered, I think more people would own it.

Thanks for the affirmation that the HiFi+ magazine test results are available; maybe its a paid feature. Could you possibly be thinking of HiFi News? That site refers to Miller Audio Research. I searched for "sme 30/12 test results" and was pointed there; it asked for login credentials though I found no way to register. You'd think if someone was offering standardized testing for turntables, that information would be readily available and commonly pointed at. Maybe I had bad luck finding it. I'm inclined to believe 'table manufacturers are honest with their testing but freely open to challenge.

It has been easy to discuss the Monaco because the manufacturer provides so much information about it. By making the claims that they do, they become easy forum fodder, easily chipped at, though I haven't seen anything here to suggest their statements are other than they say. Nor have I questioned information from other 'table makers who provide it.

Rather than starting from drive types, or technologies or falling back on brand loyalty, is it worthwhile to ask if there is any sort of priority or precedence of design properties that better tables tend toward sharing. What is important in turntable design and implementation? Or, what is important to performance associated to top quality sound? If there could be some agreement on what is important then a look at those aspects for different drive types or manufacturers might advance the discussion. If the thread hasn't gone anywhere, maybe a turn to methodology.

I think Halcro tried when he said above: "The constancy and accuracy of a turntable’s speed rotation may not be the most important facet of its performance quality, but one would think it should be a sine qua non." To me that says speed accuracy and control of platter speed are necessary conditions for top performance, but necessarily alone not sufficient.

So are there necessary and sufficient conditions for top 'table performance? Could that sort of approach get to some agreement?

For example, another necessary but not sufficient aspect of 'table design might be: Minimal noise generation and noise rejection.

If some set of such conditions could be agreed upon, perhaps debate could occur over which of these is more important and which implementation method is better. For example, someone might offer: "The single most critical element of any turntable’s performance is the platter speed control. The more accurate the platter speed control the more accurate the frequency reproduction of the turntable."

Now to some extent numbers may help drive the notions of what is necessarily important simply in virtue of the better 'tables commonly exemplifying them, for example, wow and flutter figures below a certain audible threshold. On the other hand while small differences between small numbers seem like they may not make a difference, absent other ways of accounting for sonic differences between 'tables maybe they do. I will not use numbers to tell me what sounds right but after the fact they may tell me why. Heh. Hopefully I get to retain my subjectivist reviewer card.

 

[ddk]

So, are we to conclude at this point that drive choice is irrelevant?

Getting back to the 3 original Reference tables, each tt has some very specific sound characteristics associated with its drive type and are great representatives of that technology. Frankly, I didn't expect the limited experience of people with these tts in this forum so things came to halt and conversation went a different direction. I tried to explain some of the basic qualities of each technology not to pick a best but offer different flavors for enjoyment and variety. This is one of the greatest beauties of analog vinyl that while all 3 tables sound totally different they're also all correct and musical at the same time, digital can't do that!

That belt drive/dd/idler at their very best are closer rather than further apart on speed stability, and it's other factors that lead to the marked differences in SQ btwn tt's?
If this is really true, what is the point of this thread?

It was always about the other factors Marc, speed stability has been a non-issue with better tables for decades, whatever the drive type. All of the three Reference tables are capable of accurate speed, its other factors that distinguish them from one another. I'm trying to avoid getting too specific about any one model, that's another type of dead end...

david

 

[spiritofmusic]

I'm not sure how much more I can contribute to a thread that I'm DEEPLY intrigued by, when my small ideas of interest aren't taken on by anyone. This is not to complain about anyone, my ideas just don't have any takers.
Noone is coming on and commenting on moving from belt to non belt other than me. It would be great to hear from SOME others. For me, there are distinct differences in sound presentation btwn belt and non belt, and the examples of non belt that have worked for me, SO "talk" to me, that I just can't imagine ANY belt drive example getting me back in the previous fold. I'm not arrogant enough to say this is a certainty, because I haven't heard Kronos, AF1, Continuum, Clearaudio Master Reference other than at shows etc, but the examples of idler/DD that sound great to me, ALL have an extra level of propulsion and great neutrality/warmth balance, that I've NEVER heard from belt drive. As I've been saying, that's just a distillation of how I feel, but I'm aware pretty much of others on other forums who've gone from belt to non belt esp hot rodded Garrard 301's pretty much concur.
Now, if we can't get to the bottom of why so many non belt tt's have this signature because it seems actual speed stability is identical btwn these and belt drives, then it needs someone to explain if it's the JOURNEY/METHOD that non belt drive gets up to (correct) speed that makes the difference, or whether it's a synergy btwn drive tech and the other things we all talk about ie materials used/isolation/suspension etc.
I still posit that since belt and non belt tt's all share everything else in common (more similarities than differences in plinth and platter materials/ideas of vibration management etc), then it must be HOW speed control is reached/maintained that is the dividing factor. An AF1 or SME 30 will utilise high mass and high inertia w/a belt, and intermittent servo control, a Monaco will utilise low mass and low inertia, and instantaneous servo seek and correct, and a Saskia will utilise high mass/high inertia, and intermittent high geared braking idler. I'm going to stick w/my idea that these techs are so different that even though the end result is the SAME on paper ie 0.01-0.03% speed stability, how the speed is then maintained over the course of playing an lp that imparts the character of the sound emerging from the spkrs.

Eagerly awaiting the Saskia controller designer's thoughts on his box of tricks, and where this all fits into the argument as I've represented it.

 

[PeterA]

Thanks for the affirmation that the HiFi+ magazine test results are available; maybe its a paid feature. Could you possibly be thinking of HiFi News? That site refers to Miller Audio Research. I searched for "sme 30/12 test results" and was pointed there; it asked for login credentials though I found no way to register. You'd think if someone was offering standardized testing for turntables, that information would be readily available and commonly pointed at. Maybe I had bad luck finding it. I'm inclined to believe 'table manufacturers are honest with their testing but freely open to challenge.

Tima, My mistake. It is HiFi News. Here is a link to some more information about the design from SME about their Model 30/12. Scroll to the bottom of the page for a link to the review and testing which shows speed results: http://www.sme-audio.com/turntables/sme-model-30-12-turntable

 

[ddk]

I'm not sure how much more I can contribute to a thread that I'm DEEPLY intrigued by, when my small ideas of interest aren't taken on by anyone. This is not to complain about anyone, my ideas just don't have any takers.
Noone is coming on and commenting on moving from belt to non belt other than me. It would be great to hear from SOME others. For me, there are distinct differences in sound presentation btwn belt and non belt, and the examples of non belt that have worked for me, SO "talk" to me, that I just can't imagine ANY belt drive example getting me back in the previous fold. I'm not arrogant enough to say this is a certainty, because I haven't heard Kronos, AF1, Continuum, Clearaudio Master Reference other than at shows etc, but the examples of idler/DD that sound great to me, ALL have an extra level of propulsion and great neutrality/warmth balance, that I've NEVER heard from belt drive. As I've been saying, that's just a distillation of how I feel, but I'm aware pretty much of others on other forums who've gone from belt to non belt esp hot rodded Garrard 301's pretty much concur.
Now, if we can't get to the bottom of why so many non belt tt's have this signature because it seems actual speed stability is identical btwn these and belt drives, then it needs someone to explain if it's the JOURNEY/METHOD that non belt drive gets up to (correct) speed that makes the difference, or whether it's a synergy btwn drive tech and the other things we all talk about ie materials used/isolation/suspension etc.
I still posit that since belt and non belt tt's all share everything else in common (more similarities than differences in plinth and platter materials/ideas of vibration management etc), then it must be HOW speed control is reached/maintained that is the dividing factor. An AF1 or SME 30 will utilise high mass and high inertia w/a belt, and intermittent servo control, a Monaco will utilise low mass and low inertia, and instantaneous servo seek and correct, and a Saskia will utilise high mass/high inertia, and intermittent high geared braking idler. I'm going to stick w/my idea that these techs are so different that even though the end result is the SAME on paper ie 0.01-0.03% speed stability, how the speed is then maintained over the course of playing an lp that imparts the character of the sound emerging from the spkrs.

Eagerly awaiting the Saskia controller designer's thoughts on his box of tricks, and where this all fits into the argument as I've represented it.

Many members with different perspectives contributed here Marc, you're never going to get to to the bottom of of something this complex here. Aside from Win the rest of us are simple audiophiles with none or at best minor technical understanding, enjoy the conversations & arguments sometimes they're windows for you to open and expand your experience, the mistakes are also educational. You simply have to try somethings for yourself, then these threads will make more sense than not.

david

 

[ddk]

Non measurement specs?
Keith

The company write up of the Monaco gives me insight to the designer's mind and his priorities, more often than not audio products reflect their creator's personality. Then there's the usual, materials, weights, etc.

david

 

[bonzo75]

The company write up of the Monaco gives me insight to the designer's mind and his priorities, more often than not audio products reflect their creator's personality. Then there's the usual, materials, weights, etc.

david

In that case if Keith creates a turntable, it will get stuck playing the same record

 

[ddk]

LOL!

In that case if Keith creates a turntable, it will get stuck playing the same record

Perhaps ,but it will revolve at the correct speed!
Keith.

david

 

[Argonaut]

In that case if Keith creates a turntable, it will get stuck playing the same record

This for sure!

[video]https://m.youtube.com/watch?v=F1ILPl5FQaM[/video]

 

[microstrip]

In that case if Keith creates a turntable, it will get stuck playing the same record

Probably a special record of minimal eccentricity. The speed in other records will deviate too much from the quoted specs, that were surely measured using a custom technique that does not use a record.

Or the turntable will include a centering system, like the Nakamichi Dragon - the patent protection should be expired.

 

[ack]

I still posit that since belt and non belt tt's all share everything else in common (more similarities than differences in plinth and platter materials/ideas of vibration management etc), then it must be HOW speed control is reached/maintained that is the dividing factor.

I am not sure I follow your claim here... they "all share everything else in common"??? Do you feel all [top] turntables only differ in their drive system, and everything else is about equal, regardless of whether they employ high mass/inertia or not; and therefore their sound differs ONLY because of the drive system???

FWIW, I think there are quite a number of factors contributing to a turntable's sound, way beyond speed stability and the drive system, therefore, to me, no 'table is like any other in all sorts of ways. For starers, the whole apparatus is extremely sensitive to any sort of vibrations, and this has been discussed ad nauseam I think, not to mention the fact that you see all kinds of different vibration-control implementations between manufacturers.

So I'll just add one more data point, based on a recent modification I did to my platter. I have always felt that the coupling of the LP to the platter is one of those important factors affecting sound; therefore, I deeply care for well implemented vacuum hold-downs, or other solutions that afford such tight coupling, like center weights along with periphery rings; and therefore, I don't care for any turntable that sports no periphery ring or vacuum hold-down.

So I do use such a center weight and periphery ring, but that was just not enough for me; so here's the mod: a) I have added very thin sorbothane layer to the inside of the periphery ring, where it meets the LP; b) my platter, like many out there, has a trough around the spindle area - a very shallow cut-out of sorts; I have filled that area with the same thin layer of sorbothane. Now, when I drop the center weight, I can feel the LP tightly coupled to the platter in that area, and the sorbothane absorbs vibrations. So much so that I can easily tell the improvement by simply tapping anywhere on the LP surface as the record is playing, and the amount of feedback is extremely low at normal listening levels. BTW, I have heard similar good results from vacuum 'tables. If I stop the platter from spinning and with the stylus still in the grooves, then turn the volume way up and tap again, the feedback is audible, but very subdued. Repeat the same w/o a center weight, ring and mods, and the feedback is really high, and moreover, there is ringing that lasts for about a second. Repeat the test with the center weight but without the periphery ring, and there is still feedback and ringing; etc, etc...

Tapping is one type of test... then I went on to listen... the improvement in timbre was a little staggering, as was the firming of the bottom end. I feel I am now managing micro-vibrations a lot better than before, which in return, results in clearer timbre and sound. One might argue I would get similar results with a mat... not sure (I've tried mats before) - my main goal was to couple the LP to the platter as best as possible... (BTW, the reason it took me so long to implement this mod is because I couldn't locate the right thickness sorbothane. I finally found the right product, 1.02mm thick, V10R13-04060044, @ http://www.vibrationmounts.com/Store.asp?Page=Products8.htm - the platter cut-out is exactly 1mm deep)

Just another data point...

 

[PeterA]

That's an interesting idea, ack. Have you ever tried placing a thin washer under the LP at the spindle and then using the record weight? Perhaps the weight is not heavy enough to force the LP against the platter. The SME system uses a washer to raise the center of the LP and then a clamp to tighten and force the LP against the platter surface. This is quite effective at flattening the record and creating excellent contact between the LP and the scrolled platter surface.

Also, have you tried the thin sorbothane between the LP label and the record weight or experimented with different sized record weights?

It is an interesting topic because others have reported excellent results with no vacuum, no periphery ring and no center clamp/weight and a smooth metal platter surface. What do you think is responsible for the differing opinions? Just personal taste or do you think there is an inherent advantage to tight coupling of the LP to the platter? Do you think there is any possibility of record slippage, effecting speed, caused by stylus drag pulling the LP against a smooth hard platter surface? Or is it mainly about vibration drainage or absorption and removing this energy away from the stylus?

I would think that sorbothane on the platter surface and a metal platter surface are radically different approaches to addressing tight platter/record coupling and thus sound quite different. Of course, this is a different topic than drive types effecting sound.

 

[ack]

That's an interesting idea, ack. Have you ever tried placing a thin washer under the LP at the spindle and then using the record weight? Perhaps the weight is not heavy enough to force the LP against the platter. The SME system uses a washer to raise the center of the LP and then a clamp to tighten and force the LP against the platter surface. This is quite effective at flattening the record and creating excellent contact between the LP and the scrolled platter surface.

Never tried washers.

Also, have you tried the thin sorbothane between the LP label and the record weight or experimented with different sized record weights?

Actually I forgot to mention this, I've always used a thicker layer of sorbothane under the weight, so that _it_ touches the LP, not the metal.

It is an interesting topic because others have reported excellent results with no vacuum, no periphery ring and no center clamp/weight and a smooth metal platter surface. What do you think is responsible for the differing opinions? Just personal taste or do you think there is an inherent advantage to tight coupling of the LP to the platter?

I suspect it's personal taste and/or lack of experimentation. I do feel tight coupling is paramount. And there are only a few metal platters I would care for, and aluminum is not one of them.

Do you think there is any possibility of record slippage, effecting speed, caused by stylus drag pulling the LP against a smooth hard platter surface? Or is it mainly about vibration drainage or absorption and removing this energy away from the stylus?

If nothing else, I would say it's all about vibrations, not record slippage - stylus drag is not that strong a force, but perhaps in some cases...

BTW, another small experiment I did - since you have seen my custom vibration control under the motor - was to place the same 1mm sorbothane under that motor support structure: speed variation jumped up to 1% - which tells me that some belt-drive motors better be solidly grounded for best speed performance. Apparently, the motor was rocking back and forth ever so slightly, and it's not even visible. All in all, just about everything in a turntable makes a difference, save for the logo

 

[ddk]

I still posit that since belt and non belt tt's all share everything else in common (more similarities than differences in plinth and platter materials/ideas of vibration management etc), then it must be HOW speed control is reached/maintained that is the dividing factor.

If by this you mean driving the exact same tt, Garrard 401 for example, 3 different ways, then yes, I'm pretty sure that each drive type will have different qualities and you'll clearly hear it in a half way decent unencumbered system.

david

 

[microstrip]

If by this you mean driving the exact same tt, Garrard 401 for example, 3 different ways, then yes, I'm pretty sure that each drive type will have different qualities and you'll clearly hear it in a half way decent unencumbered system.

david

Even changing the belt tension of a turntable changes significantly its sound. In top turntables the turntable bearing is designed for a type of drive - using it with another type will probably compromise the sound quality.

 

[ddk]

Even changing the belt tension of a turntable changes significantly its sound. In top turntables the turntable bearing is designed for a type of drive - using it with another type will probably compromise the sound quality.

That's very true Francisco, just imagine how much of an effect drive type has on the character of the tt.

david

 

[spiritofmusic]

I believe there is a control on the DD Dobbins Kodo The Beat to change torque w/out altering speed. And the sounds produced at different torque settings are different.
This suggests strongly to me that it's HOW speed stability is maintained that could very well make the most difference to character of sound.

 

[PeterA]

That's very true Francisco, just imagine how much of an effect drive type has on the character of the tt.

david

I'm imagining the differences between an on board and remote motor location for belt drives and the differences in managing vibrations. Even the belt material: thread, rubber, no stretch reinforced rubber. Some belt drives have dual motors and dual platters. Some belts drives balance the lateral force of the belt with an equal force in the opposite direction and others don't.

Marc, could you describe what the basic differences are between your direct rim drive and a more typical idler drive? Is it just drive wheel location? If so, how does that effect the sound?

 

[spiritofmusic]

Peter, there are more similarities than differences btwn the classic Garrard/Lenco idler drive and my Salvation direct rim drive. Vic's rim wheel is button sized, of solid Delrin, and is mounted direct onto the motor spindle, which then strongly contacts the Aluminium platter against a central "stripe"/layer of Delrin (for Delrin-Delrin continuity). The 230V DC v. high torque motor then rapidly rotates the rim wheel which now drives the platter. It takes about 20mins for the speed to fully stabilise, and I allow it to run while my tubes are warming up.
Hence direct high torque drives the platter directly. Vic very cleverly avoids the typical idler drawback of motor vibrations transmitting to the stylus in the form of rumble, by draining motor vibrations AWAY from the platter, into the motor base which is mechanically isolated from the rest of the tt.
He has taken the (controversial) step of NOT providing any servo feedback. The torque is extremely high, but speed stability is only reached after the equivalent of the first side of vinyl. At this point I re check speed, make slight changes if necessary, and this speed is good for several days, upon when the same re checking proceedure needs to be preformed. Vic found that EVERY time he introduced a feedback system involving in effect digital tech checking and adjusting of speed moment to moment a la Monaco, the sound softened/smeared, which he put down to perceptible "jitter". His motor is set and forget (for a few days, anyhow), totally analog in nature. I call it "push and listen".
High torque means that the platter is up to speed in 3s, and magnetic bearing means it comes fully to a stop when motor disengaged, in 3 mins. Remember, idlers were needed originally to get platters w/heavy 78's up to speed in seconds, and deal w/15g+ cartridges, all the while carving perfect speed thru stylus drag. Now, Vic's direct rim drive system just fills the listener w/inner security that the obstructions to perfectly maintained speed stability have no chance w/this amount of drive.

 

[PeterA]

Peter, there are more similarities than differences btwn the classic Garrard/Lenco idler drive and my Salvation direct rim drive. Vic's rim wheel is button sized, of solid Delrin, and is mounted direct onto the motor spindle, which then strongly contacts the Aluminium platter against a central "stripe"/layer of Delrin (for Delrin-Delrin continuity). The 230V DC v. high torque motor then rapidly rotates the rim wheel which now drives the platter. It takes about 20mins for the speed to fully stabilise, and I allow it to run while my tubes are warming up.
Hence direct high torque drives the platter directly. Vic very cleverly avoids the typical idler drawback of motor vibrations transmitting to the stylus in the form of rumble, by draining motor vibrations AWAY from the platter, into the motor base which is mechanically isolated from the rest of the tt.
He has taken the (controversial) step of NOT providing any servo feedback. The torque is extremely high, but speed stability is only reached after the equivalent of the first side of vinyl. At this point I re check speed, make slight changes if necessary, and this speed is good for several days, upon when the same re checking proceedure needs to be preformed. Vic found that EVERY time he introduced a feedback system involving in effect digital tech checking and adjusting of speed moment to moment a la Monaco, the sound softened/smeared, which he put down to perceptible "jitter". His motor is set and forget (for a few days, anyhow), totally analog in nature. I call it "push and listen".
High torque means that the platter is up to speed in 3s, and magnetic bearing means it comes fully to a stop when motor disengaged, in 3 mins. Remember, idlers were needed originally to get platters w/heavy 78's up to speed in seconds, and deal w/15g+ cartridges, all the while carving perfect speed thru stylus drag. Now, Vic's direct rim drive system just fills the listener w/inner security that the obstructions to perfectly maintained speed stability have no chance w/this amount of drive.

That is a most interesting report, Marc. It raises many questions which I hope you or Vic can answer.

I had no idea that it takes 20 minutes for the speed to stabilize. Why is that? I had assumed that rim drive/idlers get the platter up to speed quickly and then stay that way. You write that it is up to speed in 3 seconds, but then I'm confused about why it is not stable at that point. How much does the speed vary during that 20 minutes and then how long does it take for you to confirm the speed before you play an LP? My SME takes about seven seconds for the speed to stabilize according to the blinking light on the motor controller.

Also curious is why the speed needs to be checked before each listening session after the 20 minute stabilization period. If it is stable, then why does it need to be checked? How does the system know when it is operating at the correct speed? Is the platter speed checked, or the motor speed, or both? Is there perhaps some degree of designed slippage between the wheel and platter?

I had thought that high torque motors were used to get platters up to speed quickly. If you don't listen for 20 minutes, why not use a low torque motor if the platter has enough inertia to combat stylus drag? Then it can get to speed gradually and perhaps vibration would be less of a concern.

Why does the system go out of correct speed and need to be adjusted after several days? Does vibration change the contact between the wheel and platter? And what method do you use to check for speed accuracy? Have you noticed any change in speed from stylus drag? If so, I presume you are then confirming speed while playing an LP.

Even with the fairly heavy platter on my table, it does slow down very slightly due to stylus drag, so I confirm speed with either the KAB strobe or TimeLine while a record is playing. I know ack does the same with his VPI. The only table that I have seen evidence of not slowing down with stylus drag is Halcro's Victor DD, and that video shows three arms all playing. Perhaps David's massive American Sound platter is immune also. I have met one audiophile who claimed to be able to hear stylus drag on all belt driven platters weighing less than 100 lbs so he got a heavy platter and replaced his rubber belt with magnetic tape for tape drive and reported a more stable speed.

A German designer was designing a turntable with intensional belt slip with a massive platter weighing over 100 lbs. The idea was to get the platter up to speed fairly quickly with an idler wheel and then to disengage the wheel and let the thread drive take over only occasionally slightly speeding up the platter when it slowed down, but never slowing down the platter because the thread would start to slip once the correct speed was achieved. I don't know if this table went into production.

Sorry for all of the questions, but I am curious now about the design intentions behind your Trans Fi direct rim drive table.