Direct drive/rim drive/idler drive vs. belt drive?

Jb0194, The fact that your turntable still runs at the correct average speed after you added all that mass, especially a heavy periphery ring, is not proof that there is no deleterious effect. But I don't think the Dual has a servo mechanism at all to worry about, and I believe it's an idler type in the first place, not a DD. You would of course know better than I about that. My remark was strictly with regard to servo-controlled DD tables. Moreover, if it sounds better to you with the added gadgets, that's the bottom line.

Thanks, Ralph!

Ralphmasphere

08-03-09: Atmasphere
Axel, I regard differences in dynamics as a coloration, just like tonality and soundstage. All are **definitely** aspects of platter pad vinyl resonance control (or lack thereof).

Do you not separate the drive system of a table from the damping or lack of damping of the platter? I definitely hear differences in drive systems.

Several reputable companies have done experiments where identical systems and platters (a VPI) were driven with belt drive and then rim drive. I also read about auditions with a direct drive Teres versus belt drive Teres. Both have been discussed here at Audiogon.

I remember the designers as well as listeners saying there were repeatable and conclusive results based only on drive system, even though table, platter and mat remained the same.

Maybe some Teres or VPI guys who participated in this will chime in.

Maybe some Teres or VPI guys who participated in this will chime in.

I'm not a "Teres or VPI guy" but I play one on TV, and I already chimed in above on that very topic. Peter used to be a Teres guy and he heard that demo too. As you know, he's been replaced his Teres and has become one of those Technics Guys. Or is it, once a Teres guy, always a Teres guy? Or maybe once you've had Technics you can't ever go back?

Albertporter
thanks for at least questioning, that dynamics are not quite the same a colouration.
I yet have to hear a system sounding more on-the-point/dynamic as is with a 'harder' connected drive, by simply using a different platter or platter-mat.
That's wishful thinking to me.
It can sound 'cleaner' and may leave this impression? But lack of 'slam' and 'drive' is more related to the drive then a platter-mat, in my current experience.

"But lack of 'slam' and 'drive' is more related to the drive then a platter-mat, in my current experience."

Totally agree.

I can't seem to understand how a platter mat can improve dynamics, slam, and "drive". No matter what mat I put on my Empire or other belt-drive systems, it aint sounding like my Technics SP10. I have smoother sounding DD tables than the Technics but none can surpass the bass dynamic and slam of the SP10 due its powerful motor. I also played with an idler table with an Ashland motor and it has huge dynamic. Again, the motor. From my experience is that small motor small dynamic and if it's a belt-drive even worse, the Nottingham is one example. I do believe changing mats can change the sound and the extra mass sometimes helps smoother rotation but the sonic benefit, if any, is more of a tonal one and signal to noise issue. Again, that's just my current experience. I would love to try some TTWeight mats.

I am, I guess, a "Technics guy" for 20 years. Briefly, I circumstantially became an Empire guy. I missed direct-drive so now I am back to be a Technics guy again, with a vengeance and end up with dozen other direct-drive tables. It's been fun.

While it has been several years I do remember hearing a demo of the prototype Teres Certus. I recall that there was/is a difference between the Certus platter and that used on the non-DD Teres tables. One of the differences was the use of a significant amount of brass. This was on my mind during that demo. How much of the presentation was due to the drive and how much was due to the difference in platter material? I suspect a bit of both, and I do believe that there were differences in arm/carts. To Ralph's point, the surfaces were the same as far as I know.

I don't know if the present Certus controller offers the torque adjust feature that was on the proto. That adjustment did make for an effective demonstration of the effect of torque on the sound. At one point the torque was turned up such that the sound changed immediately from analog to digital.

Since that time I've never stopped wondering if the transient sounds I'm hearing are real or not when I am experimenting with speed. I posted earlier about my experiments with really taught mylar and a more robust controller. At present I am drawn to the sound, but my mind still asks if it sounds real.

As interesting as this all is, I feel the need to remind myself that not everyone agrees with what I think LP playback should sound like. There are many people in this hobby that prefer what I would call sluggish and syrupy presentation.

One other thing I wanted to add was with respect to what can perceived as a cartridge alignment issue, which in reality is actually a micro-dynamic speed issue. I don't know what other term to use to refer to this, hopefully you guys can get a hint of what I'm on about. I would guess this is probably more prevalent with belt drives.

Hiho,
you reflect my own listening experience and thank you for sharing your own findings on that.

Even with quite, or REALLY powerful motors like I've heard on an Transrotor Z3 or on a Thorens 2010 (motors where modified, with beefed-up controller power-supplies), due to the long thin belts they remained still more laid-back then e.g. my SME, even though one could notice some improvement in the dynamics department. Two motor yet did a little more but still just don't seem to get there.

Problem with a lot (more affordable?) DD's is the 'affordable' motor/controller as I understand it. It seems VERY difficult to get this completely right, because of the DD's 'unforgiving' 1:1 coupling.
Despite some of the ~ strange Linn 'behaviours' (some love it some don't), I think they got the motor to platter coupling just right I.E. sub-platter, short belt, powerful enough motor.
SME I think went a step further, smallish as the Papast-motor is, it pulls like a train, has a lot of torque --- BUT they had to spend some time and money on a very good motor-controller without it, it would NOT work.

The spec.: Reference oscillator is a 10Mhz quartz crystal, multiplied by 4 to obtain 40Mhz microprocessor clock speed. Driver stage has CMOS buffers/MosFet drivers with 1.2 Amp peak drive capability.
Power output stage is six high power complimentary MosFets in a 3 Phase Bridge Driver configuration.
Close loop speed control is implemented using pseudo sine wave commutation sequence and a proportional-plus-integral (PI) algorithm.

So, there you go. This is not some wall-wart using the power-line cycle for speed control. With a long 'forgiving' belt it will work fine, but the closer you get to 1:1 drive-line coupling the more need to have a close to cog-free drive with torque to boot.
Greetings,

If a turntable company has succeeded in making several versions of a turntable, essentially with different drives, while at the same time keeping the platter pad and platter signatures exactly the same, I would agree that the differences one heard in them could be ascribed to the drive.

However- the drives themselves require that the platter design be different! Thus I severely doubt that *any* company has demonstrated this successfully.

In working with the Empire into its evolution into our model 208, we found that the platter pad affected the sound, but if you did nothing to control the resonance of the platter itself, you were missing a bet. IOW, although the pad I've been working with is head and shoulders better than anything else I have seen, it still did not control the platter; damping the platter was still a major improvement.

BTW, the platter pad in question was designed and built by Warren Gehl (currently at ARC) about 20 years ago. It was used by SOTA on the first 50 to 75 Cosmos tables, at which time the formula got modified. So an early Cosmos would have some of the same advantages, if you could fix the drive. I use this pad on my personal table only.

I find it astonishing that platter pads have received little or no attention in the last 2 decades, despite the extreme importance they play in controlling vinyl resonance caused by the needle tracking the groove. Resonance control otherwise has been one of the biggest strides in turntable technology over the years- but almost no work on the place where it counts the most.

And for the record, if the mat is too soft, like a rubber mat, dynamics will be suppressed. The interface has to be exact- the pad has to be the same hardness as the vinyl, so that no energy is reflected back to the LP, yet the mat has to immediately absorb the energy. Acrylic mats are too hard, rubber and felt way too soft. Honestly if these things are not sorted out first its almost impossible to tell anything else about the table! My advice is to try it first before you knock it. The only problem is- where do you get a proper mat and for that I have no answer- there isn't one anymore as far as I can tell. That is how bad this situation is- the platter pad is one of the most audible artifacts of a turntable excluding the arm and cartridge, and there are no definitive pads even available.

Warren saw to it that a good number of serious audiophiles in the Twin Cities area had his pad (FWIW he spent about 5 years perfecting it- I personally had about 5 or 6 earlier versions before he got it right). So we have had ample opportunity to compare it on the SP-10, SL1100, Conneseur, Rekokut (idler drive), Empire, SOTA, and the like. FWIW, a salesman at one of the local shops figured out how to install the pad on a vacuum SOTA, which resulted in his getting a job with SOTA. That person was Allen Perkins, and is why the early Cosmos tables featured that pad.

Atmasphere,
hope I don't sound boring by now?
Ever bothered to look at that funny platter-pad material of the SMEs at all?
Re: >> I find it astonishing that platter pads have received little or no attention in the last 2 decades <<

Not so, I'd say.
Bonded copper-pad of TW, bonded vinyl-pad of TransRotor, bonded cork-pad by Acutus, bonded glass by Brinkmann, non-bonded felt by Linn :-), etc. those are all pads on the platter, even though they are bonded except Linn.
Does that make the difference with your definition?
Axel

Dear Ralph, I would have to agree with Axel. Platter mats (pads) have received LOTS of attention during the vinyl renaissance, both in the aftermarket and from turntable manufacturers. Just do a search of any website that features products for vinyl reproduction, and you will find dozens of candidates. In fact, there are too many different choices for any one person to evaluate. Materials include felt, rubber (or some variant thereof), sorbothane, carbon fiber, graphite, copper, other metal types, dots (made of cork, felt, what have you), and combinations of any of the foregoing, plus no mat at all. I guess what you are saying is that only the one mat made in small numbers and sold only in Minneapolis area and on early SOTA tables is really proper. Can you reveal what it is made of? By the way, many would agree with you that the mat should take energy away from the LP and therefore should be made from a material that is similar to vinyl. So why not vinyl?

If the speed of a turntable is off by 1%, which can happen to some Rega tables, you think a fancy platter mat(I am sticking to the term "mat" instead of pad just for conventionality, why change now.) can improve that? Enough said.

Lew, I myself think that is a good idea. I agree there are a lot of platter pads out there, as Axel says, its just that most of them are a joke. If you are going to make a decent pad, it should use materials science and physics- like understanding how vibration travels through materials.

Keep in mind that the stylus exerts tons of pressure on the LP. Yeah, its only a 1 1/2 -2 grams but the stylus is tiny. The result is that the LP depresses, just like ice on a frozen lake does when a car drives over it (of course, we probably see more of that up here in the frozen wastelands).

So the mat cannot allow the LP to sag- it has to stand up to it. And it has to do that while controlling resonance. That is why this is such a tricky issue- and why so many platter pads are really not even close.

I'm sorry that this pad that I and a few others have is not in production (IMO/IME it was the biggest advance in LP reproduction when it appeared). That it contains lead dust likely has a lot to do with it :)

Warren says he can't get some of the materials anymore. He also said it was very labor intensive- the materials had to be combined in the right order and with correct timing. He used a special oven to cure it. I have seen a few examples come up for sale- the last one I saw went for $1200.00. Based on that I would guess that there is a budget for someone who wanted to get serious about this.

Obviously not every table could manage this thing- it weighs about 5 pounds.

Since there are only a very small number of these made before SOTA got the rights to it, there are only a few people who have heard what it does and how profoundly it affects things. However my point here is not that I have this thing, but what it taught me: that **only** when the platter pad and platter issues are reduced to a common denominator can you have an intelligent conversation about drives. This assumes that the 'table is otherwise on speed and working right, with no 'measurable' speed issues. IOW I suspect that many here are describing other differences and ascribing them to the drive when there are more fundamental issues involved.

I cannot tell you how many times I have seen people come into a room and upon hearing something they like, immediately ascribe it to the speakers, taking nothing else into account. I believe this to be the same phenomena, since I don't know of a decent production platter pad. If someone can point me to a pad that has the exact same hardness as vinyl but it otherwise completely dead, I'll immediately make an exception. Any takers?

Dear friends: Atmasphere is spot-on in the subject. The fact that almost no one of you already have that kind of experience does not means he is wrong and you are right, please let me explain on it:

in the deep research that we make ( and still doing. ) in our self tonearm design one of the main factors for achieve our main tonearm target ( a Universal tonearm where any cartridge shows its best like in no any other tonearm. ) is the build tonearm materials especially at the headshell/arm wand.

Testing different available build materials we can't find the one that help totally to achieve our main target so we have to start a whole build material research that bring us to " build " by ourself the main tonearm build material: this is a propietary blend.

Well this propietary blend material help us to achive our tonearm main target.

Through all that research that take us several months we learn the critical importance that have the build material where the cartridge is attached ( tonearm ).
The cartridge is like a very sensitive micro that detect tiny very tiny ( microscopic ) resonances/vibrations/distortions that you and me are not aware even exist and that affect the quality cartridge performance in almost the same way between the TT plater and the cartridge.
Today I can say that that tonearm build material makes a paramount difference in the cartridge performance.

Well, I ask my fellow Guillermo why not try that same tonearm build material in a TT mat/pad and VOILA!! the differences ( in six different TT's. ) in dynamic, tonal balance, transparency, soundstage, focus, top to bottom coherence, in any single performance parameter improve ( not only different but better. ) like night and day!! lowering ( almost disappearing. ) distortions/colorations level to almost CERO!!!!

I can say that this is a unique experience and that's why I understand in a precise way what Ralph posted about that almost no one of you can't understand till you have/hear that experience.

For months and in different threads ( mostly on tonearm/TT's related subjects. ) I posted ( anyone can read it. ) the critical/crucial importance of the tonearm/TT build materials that makes a difference for the better, till today no one ( but Ralph ) gives the right importance to this main factor and you can see in this thread: everyone speaking ( one way or the other ) about motors, belts, bearing, drive system, etc, etc. I'm not saying that all those factors are not important certainly are but till today no one ( tonearm/TT designer/manufacturer address seriously ( I mean in the right way. ) the item build materials.

I know ( Lewm. ) that exist several commercial mat/pad options but no one is near of what Ralph or I already experienced and know about.

I know too that is a little frustrating for almost all of you don't have an opportunity to hear that unique " audio experience " but if in anyway serve for anyone of you my audio system is OPEN for you anytime you want it.

In the midtime we are almost finishing our tonearm design and starting our TT design ( with that propietary blend material. ) along a cartridge.

Regards and enjoy the music,
Raul.

Wow, what a great discussion. As a Galibier owner, I can't wait for RMAF to audition the new motor/controller.

I tend to agree with the opinion that while each design has its particular set of strengths and weakness (resulting in a signature sound), excellence in implementation is critical. The Saskia is a very different from my Galibier and each have their own sonic signature, however, I would be happy with either. With a well-designed system, it's not 'better or worse', it's a matter of taste.

One additional variable that hasn't been addressed is production variability. Since many of the high end tables have limited production runs, I would guess that there is variability between each table produced by a given manufacturer.

My wife and I experienced a similar phenomenon when we purchased our piano. After months of auditioning, we decided we perferred the Steinway sound. We spent many hours over two counsecutive days, auditioning 18 Steinway L models. Each piano had the Steinway sound, but every one sounded and played a little differently. On the 2nd day of our auditions, Van Cliburn was visiting the dealer's showroom and he played each of our finalists. That really brought out the individual personality of each piano. (Analogous to the difference between having your analog system set up well versus set up perfectly).

Can we get back on track talking about the genres of turntable drive system?

It's not that I don't believe the improvement of a turntable mat - of course they do - but we were talking about the TYPE of improvement, in what area the mat will improve the most and some of us simply question it will improve the "slam", "drive", or rhythmic quality, not tonal quality, that, we believe, has more to do with the drive system and, in my experience, particularly, the motor. I will be happy to be proven wrong that a turntable mat will improve across the board in every sonic area to the point where it even matches or surfaces replacing a mediocre motor with a better one. If there's cogging or speed irregularities or speed drift, wouldn't it make sense to address the motor, which is the singular active component in the entire system? For some reason, the thread ended up talking about turntable mats. Many stock Empire 208 turntables are a little fast, please illuminate me on how a turntable mat can make the speed spot on.

Back to motors or drive systems, shall we?

Question for Mr. Kelly. Is there a technical explanation on why, at least to me, most coreless motors in a direct-drive system sounds smoother to my ears? I know they've been advertised as having less cogging or coggin free and I have to admit they do sound silky smooth. They tend to have less torque and, again to my ears, less dynamic but I am willing to trade for smoother sound than just dynamics. Even on a cheap Pioneer DD table with coreless motor that I acquired recently I heard the purest smoothest violin sound from a turntable. Sonically, I am sold on this type of motor. Typically I choose a high torque core motor DD table to tape-drive my passive platter to equal the smooth sound of a DD table with coreless motore.

HiHo

Here are a few things which I can prove to be true:

1. Newton's Third Law of motion holds for turntable motors so the reaction torque reflected into the chassis will be the mirror of the forward torque applied to the platter.

2. The variation in reluctance of a "coreless" motor is much smaller than that in a motor using an iron cored stator.

3. As an iron cored DD motor rotates, the servo loop compensates for the variation in reluctance by decreasing torque as the rotor pulls towards the lowest reluctance position and increaes torque as the rotor pulls away from that position. This happens many times per revolution, depending on the slot and pole numbers of the stator and rotor respectively. The exact quantum is the least common multiple of the slot and pole numbers.

4. It follows from 1 that the torque variation reflected into and propagated through the chassis is much smaller with an ironless stator than with an iron cored.

It is my conjecture that this phenomenon explains what you are hearing. Naturally I cannot prove this so I won't say that it is *definitely* the case.

Some support for this idea comes from some engineering work done at Sansui towards the end of the analogue era where they designed a DD with two counter-rotating platters to obviate the problem (called X-99 I believe).

Mark Kelly

Dear Hiho: It is obvious that a TT build material ( any ) can't fix a mediocre motor that ca run on " speed ", but I think that is not the subject on what Ralph want to share with all of you.

I can tell you that through my TT experiences through the years ( dozens of TTs ) almost all main factors on TT performance are already addresses but the TT right build materials.

You can find several threads like this one speaking one and again the same TT topics with no single real advance out there.
I know that everyone has a lot of fun reading and making some TT changes on its systems but that main factor ( TT build material ) remain almost untouchable: I wonder why?. The " sad " issue is that almost all analog people does not care about just like you.
It is obvious that maybe does not care about because don't understand the critical importance on the TT build materials that like I posted the differences in quality performance is: night and day !!

I understand too that because almost no one already experienced what Ralph and I " live " there is not to much of what to talk/share from almost all of you.

IMHO and like Fm_loging posted: we have to evolution if we want to grow up and if we want to improve what we have.

I'm on evolution and that's why I share with all of you my findings. Stay steady where you are is up to you and fine with me.

Regards and enjoy the music,
Raul.

Mark, Just out of curiosity, do you know anything about the build of the motor in a Denon DP80, iron core or coreless? I do know that it is a 3-phase synchronous AC motor the speed of which is controlled via the servo by varying the frequency of the AC. This is different from the SP10, but I had not thought about whether the DP80 motor had an iron core or not. Indeed, I did not appreciate the significance of that fact until Hiho and you had the exchange above. I ask because the DP80 gives me the very same "smooth" feeling that Hiho experiences with his Pioneer. In a heavy slate plinth, the Denon is rather addictive.

Raul and Ralph, I hope some time it will be possible for you to reveal the nature of these especially good tt mats. It would be fascinating to find out whether both mats were made of similar materials.

Lew

The DP80 uses an iron core stator.

The distinction between Denon's "3 phase AC outer rotor motor" and Technics "Brushless DC with integral magnet platter" is largely semantic.

The Technics motor is a 3 phase outer rotor motor which includes a circuit in the motor which generates 3 AC waveforms due to the motion of the rotor. These waveforms are necessarily synchronous with the rotor. The waveforms are then amplified to a level determined by the PLL controlled servo loop and fed back to the motor drive coils. The PLL is fed by Technics famous frequency generator circuit.

Without access to the Denons circuit details I cannot say exactly how the Denon generates the frequency required to run its motor but I can say that it also employs a PLL controlled servo loop to slave the coil drive to a motion dependent signal, this time generated by a magnetic signal recorded on the platter (a primitive version of a rotary encoder). The loop presumably also controls the voltage of the drive amplifiers - if it did not the level of cogging would render the motor useless.

From a practical point of view the only difference would be in the fidelity of the drive waveform. The forward drive voltage in the Techics motors I've seen is fairly ugly, the engineers relied on the high speed of the FG servo to smooth the rotation. Denon's encoder is a lot slower so they would have to have a cleaner waveform to start with. They are both neat solutions to the central problem, neither appears to me to be inherently inferior to the other.

Mark Kelly

Thanks, Mark. That's a lot more information than I can glean from the Denon literature from that era. And the schematic is beyond my comprehension. Others, including Technics as you note, have spoken of the Technics SP10 motor as being of the DC type. Now I see that this is a distinction without a major difference.

Dear Lewm: +++++ " reveal the nature of these especially good tt mats. " +++++

that mat/pad with our build blend material is only the tip of the iceberg in relation with build materials and its importance in TT- tonearms - cartridges and maybe some other items. The mat is only one kind of use in the audio world.

No, the material that Ralph describe is different from the one we own, between other things ours has a lower weight due to the blend material used.

IMHO I think that the real importance of that build material subject is that we are starting to talk about when one or two years ago we did not heard nothing on this build factor.

Sooner or latter the TT and tonearm designers/manufacturer ( mainly ) must take " the bull by its horns " if they want to offer better quality performance products to we the customers.

I posted several times that we deserve the very poor non-evolution audio products we have because we the customers never ask for more: sometimes because a very poor know-how, sometimes because we don't care about and sometimes because we are thinking like 30 years ago ( with no evolution attitude. ). Of course there are some exceptions on both sides: builders and customers.

Here in this thread we have a precise example of that " old thinking " way: where Quiddity try to expose and sustain with numbers a few subjects/factors the next post to it say something like this: " if we go for the numbers a Yamaha will be better than a Lamm unit ".

Well I say that almost any audio " stage/performance " can be numbers related ( here and now ) if we know what to measure, where and how to measure, when to measure and with which tools/instruments we must to measure.

Lew, we are talking in this thread ( like in many other ones. ) of products designed 30-40 years ago that are competitive with today designs: turntables, tonearms and cartridges, with almost no evolution in the audio industry, why is that? I ask, who has the culprit? manufacturers or customers, I think both but mainly the customers that are manipulated by the " professional " ( some corrupted with intention and some " corrupted " by non know-how. ) magazine reviewers and that are ( the customers ) the ones that buy those very poor audio design items, yes we deserve what we have!

I think there are a lot of talent out there for design and build a lot better audio products in any single link of the audio chain but unfortunately we customers don't give to them any " sign " that motivate them to be better than what they are showing today, we are proud with what we have.

Anyway, continue with the thread subject.

Regards and enjoy the music,
Raul.

My experience with coreless motor is not limited to just the Pioneer as I have several turntables here that exhibit this silky smooth quality. The Pioneer is better to illustrate the distinctive quality of coreless motors even in an inexpensive model. I believe the later Pioneer models, the "L2" series of turntable, such as PL-50L and PL-70L all converted L2 to use coreless motor with the same specs, all employing their trademark feature "Stable Hanging Rotor" SHR, basically a fancy way of saying an inverted bearing. Anyway, I realize many top or almost top of the line models from various brands used coreless motors such as Kenwood L-07D, Sony PS-X9, JVC TT101, Yamaha GT-2000, PX-1, Pioneer PL-70LII, Sansui XP-99, et al. I owned neither so obviously I am drooling here. I am not saying only coreless motors are good. It's just that whenever I detect this kind of smooth sound, invariably it's a turntable with a coreless motor. JVC have some core motor tables approach the smoothness I crave for - I haven't listened to my SP10 for a while now. That's why I reserve the core motored tables for tape-driving purpose as the tape smooths out the tiny bit of cogging or whatever you call it for the passive platter.

Raul, I admire your forward thinking. Keep up the good fight. Yes, sometimes audiophiles got what they deserve, un-innovative products.

After chiding someone on VA over miunderstanding servo loops I should correct an error in my description of the Denon.

Where I said "it also employs a PLL controlled servo loop to slave the coil drive to a motion dependent signal...." I should have said "it also employs a servo loop which adjusts the coil drive, using a motion dependent signal...."

The master is the quartz reference.

Mark Kelly

Mark,
since you ARE in the know about PL(L), servo loops, 3 phase conversion, quartz reference, current supply ability, and on.
Have you any comment on the SME controller implementation, from what I posted earlier or any of your own more detailed insights?
Axel

Axelwahl

I don't have enough information to make an informed judgement about the SME's controller implementation.

Mark Kelly

Hiho, for the record, the Empire does not go off speed if properly serviced, and can be expected, once serviced, to run for years without further attention. I have seen the motor angle being so poorly set that the belt engages the wrong part of the motor spindle, and I have seen motor spindles so dirty that the diameter was increased. The actual spec of the stock machine is impressive- well within the specs set by the best of the DD machines.

Lew, I don't know all of what Warren put in his mat, but I understand it contains an aluminum disk, and there is a thin Sorbathane layer where the mat meets the platter, so the material is not amorphous.

Although it is by far the best mat that I have heard, it is obvious that it could be a lot better- otherwise damping the platter would not have the rather obvious improvement that it does! OTOH it might be that the best we can hope for is a platter pad that can do what I said- have the hardness of vinyl so maximum vibration transfer without reflection is achieved, and otherwise maximum deadness.

I don't know about the benefits of achieving maximum "deadness". I've run some informal experiments using different damping materials on my TT's plinth. I definitely found thet there is a point where there is too much deadening which sucks the life out of the music. Yes, you have to address gross vibrations and such, that's not what I'm talking about. AFTER you have got is pretty right this is the fine tuning. Just don't over do it.

Bob

All,

I just caught on to this thread and need to find the time to digest it in its entirety before replying, but one thing jumped out at me as I was scanning through it - Axle's comment (quoted below). I'm not singling you out Axel. It's just that your clear writing called my attention to it.

Axelwahl wrote:
The platter material / mats / pads / and other damping are ALL colouration items (excluding some really heavy lead-loaded mats adding more mass)

I contend (as Ralph does) that a compromise in dynamics is a coloration, and if dynamics are unconstrained, then you are more faithful to the music.

As far as mats and other materials are concerned, I subscribe to the following position. A part of the job of the various components in an analog rig is to transmit (as opposed to reflect) vibration down the chain at EACH and EVERY materials interface.

A mat is just one more part of a turntable - whether supplied by the manufacturer or purchased in the aftermarket. It either "works" or it doesn't. It adds another interface to the equation.

Examples of interfaces are:

- cartridge to tonearm
- tonearm to base
- record to platter
- platter to bearing
- bearing to base
- base to stand

and so forth ... until we work to the Earth's core, the sun burns out, and life as we know it ceases to exist (grin).

Material selection is critical here, with one consideration being to match the relative speeds of sound of the interfacing material pairs.

Think of how a flat stone can be thrown so that it either skips across a lake or alternatively passes immediately into the water.

There's much more to this, but I don't have the time to explore it at the moment.

I'm deep in the throes of supporting Mark's controller design, but I'll try to find the time to read this thread from start to finish.

Cheers,
Thom @ Galibier

I would just like to add my five-penneth.

Aren't the idler wheel and belt drive systems completely differing technologies/sciences? On the one hand (Belt) you have a large mass in rotation, a motor that only really pushes when the platter slows, and a flexible drive system (belt). One the other (idler) you have a clamp sytem where the idler wheel (inside rim) pushes the platter away from the centre bearing or (outside) pushes the platter towards the bearing. The platter is trapped between the bearing and the idler. (Depending where you are standing both idler types are the same.)

I don't see how a comparison can be made. They are just different and both work well or badly depending how well they are engineered and built.

:-)

Clarkie

I can't see where the distinction lies. In both cases you have a passive inertial element (the platter), an active source of energy (the motor, which also has inertia of its own) and a transmission (belt or idler) which links them.

The motor's function is to replace the energy lost from the system. The transmission's function is to adapt the speed of the motor to that of the platter.

Most of the distinctions made betwen belt and idler can be viewed in terms of how lossy the transmission is, it historically having been the case that belt TTs were made with a much lossier form than were idlers.

I think the inertia of the motor is also important but misunderstood.

Mark Kelly

Mark,
This aspect of inertia of the motor is something I did not really understand the last time it came up (because I assume you are not referring to motor inertia the way the Micro SZ-1 motor does it). If you were talking about that, then I can start to see where you see the similarities between an idler with a high inertia motor and a belt drive with high inertial motor where the belt slippage issue is addressed by bringing the slippage away from the belt-platter interface and to a kind of clutch mechanism which allowed the motor to more or less "apply" the belt to the platter with even force on both drive side and lee-side of the turn.

T-Bone

Maybe you have me confused with someone else.

I have never advocated the use of any form of slip in a turntable transmission. I understand the theory of it being used in an attempt to reduce cogging but I think it's the kind of half baked idea propounded by people who really don't understand the mechanics of TTs. You will have noticed that there are a lot of them about.

I have pointed out many timnes that belt creep (and idler creep) is an inevitable consequence of using compliant coupling materials but that could not be construed as advocating its deliberate introduction.

Mark Kelly

Mark,

I have not mistaken you for someone else. I am aware of your issues with belt creep. In fact, because I was trying to dance the long way around a subject which I think may be of commercial importance to you, I ended up mis-communicating. Please ignore my comment.

Play on ladies and gents...

"I understand the theory of it (belt creep) being used in an attempt to reduce cogging but I think it's the kind of half baked idea propounded by people who really don't understand the mechanics of TTs." - Mark Kelly

I cannot agree more. Well said!

Once again, if a turntable needs a soft rubber belt to reduce coggging or noise from the motor in order to sound competent. Get a different motor or change to a different drive system. It's just that simple to me. Some think platter or bearing is more important because motors don't get the blink blink like a thick shiny platter and they are always tuck away in the back or hidden and do not get the attention they deserve.

Mark: I am no expert but my experience is that the heavier the platter on the belt drive T/T the more likely we are to have less variations in speed. I owned a Michell Gyrodek for some years and always knew that its speed stability was marginal. It wasn't until I purcahsed my present Acoustic Signature Analogue One Mk 111 that I realized how bad the Gyro had been. I know that things are relative. I have to assume that both decks are well engineered within the requirements of each design. I am inclined to believe that the real reason that the AS is better is because the platter has higher mass. I am not aware of how heavy the platters are on idler T/T's but would make an educated guess that they are much less than the AS which I will use as my reference.

In the case of the idler T/T at no point is the platter allowed to rotate in a 'free' state. The idler drive is always in contact and driving, even if we admit that there IS some compliance in the rubber driving material.

I stand by my firtst statement that the two systems are completely different and both can work or fail. It's really only about engineering.

Clarkie

Hiho,
well, well, well.

What you seem to overlook is the reality of it all. Just have a look at HOW MANY tt manufacturers use exactly that 'rubbished' approach and then ask yourself why.

I think a STABLE AC motor (not DC which is prone to drifting) is just cogging, some more, some less, even 3 phase, and so along comes the soft, long, or what ever, belt to 'fix' it. At the same time mass is added, has to be added to the platter, to counter act the soft belt drives lacking dynamic performance.
Practically ALL tt's that make the top grades (Hi-End rating > 100 points) in all known to me German Audio Magazines are designed that way.
Then a 'controller' may be added (in some cases more of the name then the real thing), at extra expense.

The question: how much does one actually hear the difference?
Point to add: it was one of these 're-worked' Garrarde's (by Loricaft) the wound up pretty much on top of the heap. It was superior DYNAMIC performance that did it to the testers... alas not the high price with some questionable suspension on squash-ball, and other sundry items.
Greetings,

Clarkie

You appear to be making two statements:

1: High mass platters improve the speed stability of belt drives

2. The transmission in an idler is stiff, so the motor is tightly coupled to the platter.

and following them with a conclusion:

3. Therefore "the two systems are completely different".

The two statements are reasonably uncontroversial, but I cannot see how they are supposed to lead to your conclusion.

The obvious implication from your statements is that belt drives are necessarily less tightly coupled than idlers and that the platter in a belt drive is somehow free to rotate in an uncontrolled manner. This is supported by a statement in your previous post where you said that a belt drive has "a motor that only really pushes when the platter slows".

This is completely wrong. If the two systems are designed to have the same drive compliance then they are by definition equally tightly coupled. There is nothing to prevent this being achieved in practice; that it has not been seen as a desireable goal by the designers is an historical artefact, not a matter of physical necessity.

Axelwahl

you have confused the terms slip and creep in my post. They are not the same thing.

Mark Kelly

Sorry that last part was measnt to be for Hiho not Axelwahl.

.
Axelwhal,

Just because many so called "high end" - a relative and useless term to me - turntable manufacturers use soft rubber belt does not make it right or enough to overwhelm alternatives. These days turntable manufacturing is a cottage industry, compromise has to be made for ease of production. By the way, what exactly is your question or point, as you seem to reinforce what I said in my last post? I personally do not subscribe to heavy heavy weight approach as it will reach a point of diminishing return. I rather have a better stronger motor to get the dynamic I want than to get it from a high mass platter. To me direct-drive is the most elegant approach or belt-drive with non-compliant material or idler-drive with a quieter motor. Basically, all three drive systems can sound good with different approaches to compensate their inherent problems. That's why is called engineering, isn't it?

The Monaco turntable is the most desirable turntable for me if I can afford it as it suits me from a technical and aesthetic standpoint. It's elegant. I haven't heard the sound but I have a feeling I will like it.

.

.
Mark,

Sorry, I should have quoted you completely instead of edited. Can you elaborate on the difference between belt slip and belt creep? I know you posted extensively on a different forum. Care to briefly illuminate the less technical one here? Thanks.
.

A belt creep is someone who has a size 54 waist, but still uses a size 34 belt, hung WAY low over the grossly protruding beer belly :-)

Belt slip is when he reaches for something over his head and his pants fall down :-))

Does efficient bearings like Clearaudio Magnetic Bearing bring belt drive/high mass platter design CLOSER to low mass/direct drive design??

Hiho,
y.s:
>> I rather have a better stronger motor to get the dynamic I want than to get it from a high mass platter <<

As you have noted I am with you actually. BUT without (and I said it much earlier) a VERY! good motor controller your wish is not going to be much of an improvement over a high mass platter - maybe quite the opposite!
The same applies to DD tables if not even more so.
Hard drive-line + so, so, controller = incoherent sound.
There are hardly any VERY good motor controllers commercially offered for all I know. So be careful what you wish for.
To my knowledge there is nowhere near close a solution, even with 'upper-class budget' , to replace soft belt and mass platter -- also supported by my mentioning these Audio magazines.
But if you are fine blowing ~ 25k plus, then you might even get a decent controller with a lighter = more dynamic! platter.

Therefore my point = simply - a Reality-Check!

Greetings,

"without a VERY good motor controller your wish is not going to be much of an improvement over a high mass platter - maybe quite the opposite!" - Axelwahl

I should be clear when I said "good motor" I also infer good motor and its associated controller as a system. Good motor system, that is.

My motor for tape driving is the Technics SP-10mk2 which I think is good enough for me.

Nilthepill, To answer your question with my opinion, no. I don't see how a magnetic bearing, which acts in the vertical plane only, can possibly have such a dramatic effect on the drive system, which is mostly operating in the horizontal plane. But your question assumes that low mass/direct drive is inherently superior to belt drive/high mass, which probably is not categorically true. Success of either design philosophy will have a lot to do with execution. I am thinking that, while I personally have begun to favor the low mass platter/direct- or idler- drive turntables based on my listening, this approach is the most difficult and potentially expensive to perfect. Whereas I think it is easier to get "decent" results with a high mass platter/weak motor/low compliance belt. Maybe that explains the predominance of the latter type of turntable in the "high end". I'd love to hear a Grand Prix Monaco myself. I wonder whether the carbon fiber adds a coloration, for one thing.

Hiho

Consider the speed of three things: firstly the belt on the drive side of the motor pulley, this being the section which is pulling on the platter; secondly the belt on the non-drive side of the pulley, this being the section where the belt is feeding off the pulley onto the platter; and thirdly the surface speed of the pulley itself.

Belt slip is where the speed of both parts of the belt is slower than the surface speed of the pulley.

Belt creep is where the belt speed on the non-drive side of the pulley is slower than the drive side, so the belt creeps over the pulley to make up the speed difference. This is because the belt is stretched by the torque it is transmitting and that amount of stretch must relax over the pulley. If the belt were equally stretched on both sides there would be no tension difference and thus no torque transmitted.

Mark Kelly

"If the belt were equally stretched on both sides there would be no tension difference and thus no torque transmitted."

Thanks for the explanation. On my system, the active pulley is the same size as the passive platter so I would have to assume there would no or little belt creep, right? I use two identical turntables to drive each other via a VHS tape. So far this is the best sound I got from a belt-drive system and the only thing that can match it is a quality direct-drive turntable with a coreless motor. Since I am lazy, I like the convenience of direct-drive table with some automatic features. :-)

Hiho

The creep is proportional to the strain in the belt divided by the parallel sum of the wrap lengths of the pulley and platter.

The compliance of the mylar belt is quite low, so there's not much strain present. The wrap length of your "pulley" is about 500mm rather than the 10 - 50 mm of conventional drives.

Your system will give about the lowest creep available (this side of direct drive of course).

Mark Kelly