A Direct Comparison: Technics SP10 Mk3 and SME Model 30/12A

microstrip said:

Morricab,

Many thanks for fueling my points - this particular motor suffers from the same problems of core motors - the moving field is created by discrete coils that create a moving magnetic field . In such a simple arrangement they must be driven by a special algorithm with correction that compensates for the typical non linearity of such discrete arrangement - these coils have large gaps between them! Go on reading how it works and what they had to do to help solving, surely with relative success, the intrinsic problems.

"Additionally a large rotating mass of 500 grams, achieved by using a nickel-plated steel motor body, works likes a flywheel. This drives the platter of the turntable with a very even force and reduces vibration".

This type of drive is used, for example, in cheap motors for diskette readers. Brinkman probably optimized the controller and created a fancy, geometry, keeping costs low. This motor costs a lot less than a custom cored motor. It also has some more problems that a classical cored geometry, such as those caused by vertical variable drag.

What do you think of marketing literature that goes on saying "The new motor generates more torque and is therefore able to reduce the start-up time to a few seconds, no problem for the new vacuum tube power supply »RöNt II«, which is also able to handle the direct drive motors as well. ".

IMHO DDK explained fairly well why designers are developing such fancy motors for belt turntables in another thread - no one is currently able to supply the good old synchronous motors of yesterday.

BTW, I have reasons to consider that Brinkmann turntables are excellent sounding, but not because of their literature.

There is very little in common between this motor and the extremely well designed coreless motors of the Calliburn or the VPI, made by Thin Gap, except they obey to the same basic laws of electromagnetism!

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No, again you miss the point of the difference. The IRON in the stator of a normal motor makes magnetic attraction and repulsion to the permanent magnets in the rotor. THIS is what causes cogging. Remove the iron you remove the magnetic attraction and repulsion from the iron poles. By going coreless you remove this issue...that doesn't mean there are not other, geometry related issues with motors. By sinusoidally commutating you can bridge between coils as long as there is not the iron there mucking things up.

DDK has his opinions and is welcome to them. They are by no means gospel. I don't see why cheap easy to build synchronous motors would be hard to source. The printed motor (pancake motor) that I have cost me over $1K. A synchronous motor with suitable torque costs maybe $50.

Brinkmann's do sound good because of their design. Their literature merely explains the design and they seem to be a pretty modest and factual company from my experience also talking with Helmut Brinkmann.

I never said Brinkmann's motor was the equivalent of what went into the Caliburn, that seems like a strawman you want to setup. You have to ask yourself though why Continuum used such a coreless motor in their no-holds-barred design rather than a good old synchronous motor...same for VPI, why such an extreme motor if it really doesn't matter so much as you clearly seem to imply?

They all do follow the same laws but different implementations of that law will provide stunningly different results. Removing iron from the circuit reduces torque but removes a main barrier to smooth motion at low speed. Sure at 300 or 1000 RPM it matters very little, so for belt drive it would SEEM less important (Continuum thought otherwise as does Brinkmann and I suspect others) but for a drive turn at 33.33 RPM smoothness matters a lot. The jerkiness cannot be eliminated when it is inherent in the electromagnetic circuit...the rotor magnets are attracted and repelled by the iron poles...it is physics and can't be undone by fancy commutation. Just like crossover distortion in an amplifier cannot be corrected by negative feedback...only the right bias to "smooth out" the transition works.

Going slotless removes further motor noise but doesn't necessarily improve torque ripple.


""Another way to avoid cogging is to go with a coreless design. The rotors of coreless motors consist of skew-wound wire with no core. They offer lower inertia and inductance, as well as zero cogging. Of course, as with all things in engineering, there are trade-offs. Cogless designs may offer smoother torque but that comes at the price of lower torque all the way around. For constant-speed and contouring applications, a coreless motor may provide the best results.

For an application moving at constant speed, the frequency of the cogging depends the speed. By choosing the proper drive and designing the control loop to minimize the amount of gain at that frequency, system designers can minimize the effect of cogging."

"Ultimately, it’s a matter of tradeoffs. For many applications, cogging torque has little effect. In the case of a continuous-motion application like scanning or contouring, however, cogging can be a problem. “Manufacturing or inspection, those tend to be some sort of contour moves where you need smooth motion,” says Profeta. “Cogging can affect you, even if you’re doing a positioning application. You have to ask yourself what type of positioning application you’re doing and does this make sense or no.”

These quotes come from motion control online.

It is clear that industry at large prefers cogless motors for applications where high torque is not required but smooth continuous motion is required...like spinning a turntable perhaps?? This is why the Japanese designers went this way 40 years ago and why new designers are returning to this after a "dark ages" of only synchronous belt drive TTs.

IMO, the printed armature motor could be the ultimate TT motor. It has virtually zero torque ripple by design. It is brushed with 150 or so "slots" per rotation so not as silent as a brushless design but as a DD motor at low speed I have found it to be silent.

http://www.printedmotorworks.com/wp...-motor-versus-conventional-electric-motor.jpg

"With no magnetic material present in the disc, undesirable ‘cogging’ is completely eliminated. This produces perfectly smooth low speed operation and continuous torque down to zero RPM. Torque output in the flat armature motor is not limited by saturation and instead directly proportional to current. At the same time, speed is directly proportional to voltage."

Interesting motor from the 1970s Teac TN-400: https://blogs.yahoo.co.jp/hsgwhz/10589863.html Not coreless but a serious attempt to minimize a normal motor with 20 poles and 60 slots! Probably not as smooth as a printed armature motor but maybe needs a less sophisticated controller.

I haven't been inclined to disassemble it but I must ask Herr Strohmetz (STST) more about his motor.

Marc you can always have a listen to my Kuzma.

Ha! Thanks for the offer Dave.
I’ll make the trip up to Wales soon.
Do you run the 9”, 12” or 14” 4 Point?
I did hear a Stabi M w 14” recently, but tbh it was in a rig I didn’t particularly warm to, and the visit was a little stilted.

PeterA said:

XV-1, those are two lovely turntables. Congratulations. I am not surprised that you hear none of the hardness or mechanical haze that Al M., David, and I all heard from the SP10 in my system. I have read many outstanding reports of the wonderful sound of the SP10 and it has indeed sounded much better in David's own system. These glowing reports are one reason I wanted to hear the table in my system. I was also curious if I could identify through listening a difference which I could attribute to speed accuracy and consistency. It is sounding more and more as if there was an incompatibility issue with my system or an implementation problem with the platter mat, some modification, some lack of the right modification, etc. None of these refurbished SP10s seems to have the exact same plinths, level of modifications, arms and cartridges. There are just so many variations among them.

I had no idea about the CU180 mat being upside down. That is worth David investigating. Yes, it is a very snug fit and he will need to be very carful when removing it to flip it over. That may very well solve the problem, but then again, David reports that the table sounds fine in his system, so who knows? We will investigate in time.

Your comment about the WOW moment is interesting. I understand about a component like a pair of speakers being placed in a new system requiring time to be properly positioned and broken in. Same with a new amplifier which may or may not have compatibility issues with the speaker load it is being asked to drive. Perhaps even with equipment racks and cables which may need time to settle. However, with a source component, I would think that there is less of this work required for it to function properly. We did give this five full days and spent much time adjusting things with the location and isolation of the controller, the arm/cartridge adjustments, etc. We worked pretty hard to optimize the sound over those five days, including phone calls to two people very familiar with the turntable, plinth, mat, Vibraplane, arm, and cartridge.

Finally, at the end of your post, you bring up particular traits specifically associated with turntable drive types. This one direct comparison surely does not answer the question for me about whether or not we can attribute particular sonic traits to turntable drive types, but it is a question that has always intrigued me. I just have not had enough experience with different turntable drive types in familiar systems to reach conclusions. Are you saying that in general, drive types have a sound? Spiritofmusic seems to believe this based on what I gleam from his writings about BB, idler/rim and DD. And it may certainly be the case with lower cost and poorly implemented designs, but I wonder if as budgets increase and restrictions are lifted, whether these kinds of sonic differences begin to be less noticeable. For instance, reading ddk's threads, it seems that the EMT and American Sound table sound more similar than either does to his TechDAS AF!, despite the fact that the latter two are both belt drive designs. Yet, with the exception of the EMT, he seems to prefer belt drive designs over all others. And then there is MikeL switching from a DD to BD table. I imagine that he hopes the AS will give him "more" of the good things he hears from his DD NVS rather than a "different" sound based on drive typology.

This thread has had some interesting posts, and I received a call the other night from a manufacturer who told me he once owned the two tables in this comparison and heard basically the same differences that I describe. So, it seems to me that there are varying opinions about the sound of these two tables, and as it has been suggested, this is all so dependent on system and room context, set up, listening biases and subjective preferences, that this is just one more data point around which we can focus to discuss ideas.

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Hi Peter

certainly not lumping all DD's and BD's in the same bucket. I am talking about personal experience including SME 30, although I have not heard the 12 inch arm. That a design like the SP10mk3 that is approaching 50 years of age still generates such interest and debate is testimony of what the Japanese were doing with their very best DD's in the late 70's early 80's.

regardless of drive technology, one would certainly expect spending 6 figures on a turntable are doing so because they are sonically better than any table that costs less.



ps - I just picked up a NOS EPS-P100ED4 stylus for my technics EPC-P100Cmk4 cartridge. Sounds amazing and in the same league sonically to any cartridge I own or have heard. but that is another whole debate

cheers

Marc

The 12" although in reality it is more like 11", Greg said he thought the 14" was not an improvement. I have the ref313 (12") as well.

Shane, thanks very much for your summary. When you say DD don't hold on to the notes as long as BD, do you mean that in a positive way, that decay is better?

morricab said:

No, again you miss the point of the difference. The IRON in the stator of a normal motor makes magnetic attraction and repulsion to the permanent magnets in the rotor. THIS is what causes cogging. Remove the iron you remove the magnetic attraction and repulsion from the iron poles. By going coreless you remove this issue...that doesn't mean there are not other, geometry related issues with motors. By sinusoidally commutating you can bridge between coils as long as there is not the iron there mucking things up.
(...)

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Not so simple. When the motor is operating, the magnetic field of the stator, resulting from the currents flowing in the coils and the iron geometry makes the magnetic attraction and repulsion to the permanent magnets in the rotor. The stator magnetic field is the sum of the fields created by each set of coils. The controller optimizes this drive to have an uniform torque, minimizing torque variations. Typically a sinusoidal drive would create an harmonic variation of torque along rotation. The controller compensates for it, as well for other non linearity. This also happens in a coreless iron, although advanced designs such as those very expensive SOTA we both referred really minimize the need for it.

When people rotate a non-energized cored motor, they feel the poles. As they do not feel them in a coreless design, they wrongly assume that all cored motors cog and coreless motors do not. Do you believe that the coreless motor of a $30 disquette drive is cog free?

Anyway our interest was comparing the designs from the 70's and you could not bring any new technical information on them, just the general marketing claims. Even the technical information about your turntable is too scarce to elucidate us, I could not compare it with the available information and technical manuals of the SP10's.

Sorry, I will not answer to general quotes.

bonzo75 said:

Shane, thanks very much for your summary. When you say DD don't hold on to the notes as long as BD, do you mean that in a positive way, that decay is better?

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Hi Ked

That would depend on the listener. For me it is a positive. I like how well done DD starts and stops notes quickly without affecting the true tone of instruments. the more complex the music, the more insight one see's into the music. in direct contrast, BD could be seen as slight blurring of instruments.

What are your thoughts?

XV-1 said:

Hi Ked

That would depend on the listener. For me it is a positive. I like how well done DD starts and stops notes quickly without affecting the true tone of instruments. the more complex the music, the more insight one see's into the music. in direct contrast, BD could be seen as slight blurring of instruments.

What are your thoughts?

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Yeah I agree which is why I jumped on that statement to check your observation. I don't have as much experience with DDs, Mike's I dismissed as uber, but I found many belts cannot handle complex symphonies well, while on the sp10mk2 that day the resolution was high and notes were clear and musical. Things held together better, there was a flow of energy - When belts do have a decay, they have a different decay, a bit wavy like, while the DD decay seems right to me. Caveated that my sample set is insufficient and I need to up my DD listening experiences - Kenwood, Kodo, more technics. But I need to compare with belts in same system sometime to confirm.

One of the biggest upgrades that I have done to my Linn was to add the Radikal D power supply. I believe that a belt drive table, with a very good isolation system and a highly accurate DC motor based power supply will put a smile on just about anybody's face. IME, the Radikal D speed control made a very large difference vs. the older AC power supply/speed control. Speed accuracy of the LP12 is now understood to be of prime importance, which certainly has paid off in massive increase in SQ. As to the belt drive vs. DD drive issue, I can easily understand why Peter A heard what he did with his comparison of his SME to the DD SP10Mk3. Only in the very deep bass might the SP10 mk3 be superior...everywhere else, not going to happen...as Peter discovered.
BTW, I am actually not that much of a believer in 12" arms....IMHO the 9" version can be more resolving...simply because it is going to be stiffer. I think MF has the same opinion now.
Pity so many a'philes are now discounting the old fruit box ( Linn LP12), having never heard it with the new upgrades that are so very very impressive.

guyser said:

I haven't been inclined to disassemble it but I must ask Herr Strohmetz (STST) more about his motor.

View attachment 36762

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Yes, that would be most interesting...

Davey, what difference in SQ did you hear due to the change in speed control?

DaveyF said:

One of the biggest upgrades that I have done to my Linn was to add the Radikal D power supply. I believe that a belt drive table, with a very good isolation system and a highly accurate DC motor based power supply will put a smile on just about anybody's face. IME, the Radikal D speed control made a very large difference vs. the older AC power supply/speed control. Speed accuracy of the LP12 is now understood to be of prime importance, which certainly has paid off in massive increase in SQ. As to the belt drive vs. DD drive issue, I can easily understand why Peter A heard what he did with his comparison of his SME to the DD SP10Mk3. Only in the very deep bass might the SP10 mk3 be superior...everywhere else, not going to happen...as Peter discovered.
BTW, I am actually not that much of a believer in 12" arms....IMHO the 9" version can be more resolving...simply because it is going to be stiffer. I think MF has the same opinion now.
Pity so many a'philes are now discounting the old fruit box ( Linn LP12), having never heard it with the new upgrades that are so very very impressive.

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took them a long time to come around though...

microstrip said:

Not so simple. When the motor is operating, the magnetic field of the stator, resulting from the currents flowing in the coils and the iron geometry makes the magnetic attraction and repulsion to the permanent magnets in the rotor. The stator magnetic field is the sum of the fields created by each set of coils. The controller optimizes this drive to have an uniform torque, minimizing torque variations. Typically a sinusoidal drive would create an harmonic variation of torque along rotation. The controller compensates for it, as well for other non linearity. This also happens in a coreless iron, although advanced designs such as those very expensive SOTA we both referred really minimize the need for it.

When people rotate a non-energized cored motor, they feel the poles. As they do not feel them in a coreless design, they wrongly assume that all cored motors cog and coreless motors do not. Do you believe that the coreless motor of a $30 disquette drive is cog free?

Anyway our interest was comparing the designs from the 70's and you could not bring any new technical information on them, just the general marketing claims. Even the technical information about your turntable is too scarce to elucidate us, I could not compare it with the available information and technical manuals of the SP10's.

Sorry, I will not answer to general quotes.

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I would love to drop this now but I really can't leave it with you stating something that seems to be counter to pretty much everything written regarding the topic on the web. Iron in the core increases the torque ripple in a motor compared to a coreless design whether or not it is energized...it might no longer be called cogging torque (the definitions are not completely clear on all sites) but the magentization impacts the fluctation of the torque during rotation in ways not experienced when an iron core is not present. This is observed in actual measurement and particularly at low speeds. Tricks can be played to lessen it but not eliminate it. You are right that not all coreless designs are torque ripple free but there are some that are completely torque ripple free and as a class have significantly lower torque ripple (not to mention no cogging torque) overall than an iron core motor and are nearly universally the motor of choice where low speed and smooth continuous motion are needed. Show me something to the contrary.

bonzo75 said:

Yeah I agree which is why I jumped on that statement to check your observation. I don't have as much experience with DDs, Mike's I dismissed as uber, but I found many belts cannot handle complex symphonies well, while on the sp10mk2 that day the resolution was high and notes were clear and musical. Things held together better, there was a flow of energy - When belts do have a decay, they have a different decay, a bit wavy like, while the DD decay seems right to me. Caveated that my sample set is insufficient and I need to up my DD listening experiences - Kenwood, Kodo, more technics. But I need to compare with belts in same system sometime to confirm.

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Hi Ked
There is a Wave Kinetics NVS for sale on Audiomarkt for 17k euros in case of interest
Probably easier to find with Hifishark.

Barry2013 said:

Hi Ked
There is a Wave Kinetics NVS for sale on Audiomarkt for 17k euros in case of interest
Probably easier to find with Hifishark.

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Heh thanks but too early.

morricab said:

I would love to drop this now but I really can't leave it with you stating something that seems to be counter to pretty much everything written regarding the topic on the web. Iron in the core increases the torque ripple in a motor compared to a coreless design whether or not it is energized...it might no longer be called cogging torque (the definitions are not completely clear on all sites) but the magentization impacts the fluctation of the torque during rotation in ways not experienced when an iron core is not present. This is observed in actual measurement and particularly at low speeds. Tricks can be played to lessen it but not eliminate it. You are right that not all coreless designs are torque ripple free but there are some that are completely torque ripple free and as a class have significantly lower torque ripple (not to mention no cogging torque) overall than an iron core motor and are nearly universally the motor of choice where low speed and smooth continuous motion are needed. Show me something to the contrary.

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Well, I write what physics and text books written by engineers and scientists on electrical motors say about the subject and tried to explain it in a quick way, surely oversimplifying the problem - e.g. we are freely, some what incorrectly would real experts say , using terms such, "cog", "cogless", "cogging torque" or "torque ripple".

You go on answering with web quotes from turntable or coreless motor manufacturers, avoiding the fundamentals. All motors have cogging issues, people using them can correct them with "tricks", then the system becomes "cogless". What counts in the end is the result they achieve after correction. Electrical motors have not been developed specifically for turntables, turntable manufacturers must understand them to improve their performance, as they will impair a sound signature in the turntable.

You are referring to the problems at low speed - we should remember that nowadays low speed in a blessing, not a curse as forty years ago. Motor controllers are now implemented digitally using microprocessors, DSPs and DACs - low speed means more time to compute and correct non linearity problems in real time, achieving cogless motors independently of the technique.

And remember that market choices and acceptance in general industry is mostly due to the performance for money and specific usage, not absolute excellence. We can not extrapolate excellence in the high-end from industry market shares. BTW, probably in the end we will find our divergence is mostly due to the usual dynamics of high-end semantics.

BTW, to prove I also know how to use google I quote an isolated sentence that is supposed to show my point “There's a perception that if a permanent-magnet motor has a lot of cogging torque it's not a good motor but that's not true,” says motor designer and IEEE fellow Jim Hendershot, co-author of Permanent Magnet Brushless Motors and Generator Design. “Once you power the motor, that cogging torque disappears.” .

bonzo75 said:

Davey, what difference in SQ did you hear due to the change in speed control?

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That's a good question.
Quick answer is....notes were far more accurate as to timbre resolution. Therefore, high frequencies were more accurate leading to major imaging improvement, the bass firmed up. Now the space between instruments was more defined and easier to hear.
An example of this is on the LP...Doug Macleod " Come to Find", before the sound of Charlie Musselwhite's harmonica was a little distant and did not have the 'bite' that the real instrument brings to the room, now it is almost as if Charlie is in the room.

If you have not had the chance to listen to 'maxed' out LP12, which most people certainly have not, and on a good system ( in the UK, a lot of time they are demo'ed with Isobariks or some other poor choice of speaker and gear); then I would highly recommend a trip to do so. You will be amazed at the difference between your recollection of the sound of the LP12 of yore- and today.
PM if you like and I will tell you of a friend who is giving up a highly thought of multi $$$$ table ( here on WBF and other forums) to replace it with the LP12 Klimax Radikal D. For very good reason!

morricab said:

took them a long time to come around though...

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Indeed.

Ivor was against it for years.....I have no idea as to what changed his mind! However, it's a very good thing that someone or something did.