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

Peter, I really don’t think you need to do it. I think it’s perfectly ok to settle on an opinion that DD is to yr ears not as involving as belt, and moreso, decidedly less natural.
For my part, I do find it fascinating that Mike L has gone to belt drive in the form of the AS after, what, 15 years as a deep convert to DD w the Rockport and NVS.
Re my preferences, I’d certainly love to reassess them .
I’ve had a chance to hear a low torque belt drive recently, the AMG Viella, and it did nothing for me. However the higher torque Kuzma Stabi M and XL4 were much more to my liking.
Maybe I will return to belt drive w the Spec thread drive which has a combination of simple engineering solutions I really admire, and at a more palatable price than yr SME 30.
And I retain the opinion that idler drive done properly has the potential to present DD prowess on dynamics and speed, but not at the expense of coldness of presentation. To this end I’m actively investigating a fascinating all-new, take no prisoners idler drive approach.


You would like a Voyd/AN TT then. I had a 3 motor Voyd with Acrylic platter before the Yamaha and it was very dynamic and involving...but also perhaps a bit noisy and "dirty". I had Helius Cyalene arm on that one and split phase PSU.
 
(...) Albert has gone for a more forensic, detail mining SP10 Mk3, that works well counterbalanced by a warmer, more forgiving tube amp chain. (...)

His speakers are the enormous Focal Grande Utopia EM and he recently has been using the Audio Research Ref 250's - neither of them suggests a warm, forgiving environment.
 
Dear Spirit,

Your view on noise floor of an idler drive is quite contradicting to what I hear from my EMT 927. Even when I take out my grounding cable from the EMT, I find its noise floor surprising low..as low as the AF1 and the Kronos. Amazing actually, given it is 56 years old with just normal cheap cables.

Kind regards,
Tang

would love to hear that. I have heard the EMT 930 but not the 927.
 
You would like a Voyd/AN TT then. I had a 3 motor Voyd with Acrylic platter before the Yamaha and it was very dynamic and involving...but also perhaps a bit noisy and "dirty". I had Helius Cyalene arm on that one and split phase PSU.

I spoke to the guyser, who is the person at whose place I heard the sp10mk2 and started my conversation with Peter. He was involved in the design and build of this Voyd back in the days and later worked for Peter Qvotrup. He said he tried the SME V and got similar results to what Peter described, and now he is using the Groovemaster with the Etsuro Urushi which I heard. He said with this combo, as well as the FR arm and the FR carts, this problem went away, so SME V is not working with the technics on his double layered slate plinth. He also said the arm rigidity matters and he uses plywood arms so that he can swap, he tried aluminium before and did not work well.
 
(...) 1) The motor is coreless and on the SP10mk3 I don't think it was, so you have potential cogging and torque ripple issues(...)

Why should a cored DD motor have more potential for cogging and torque ripple issues than a coreless design? We are addressing a motor spinning at less than one revolution per second, not a high speed turbine!
 
I’m not sure if Peter’s SP10 v SME comparisons will tell him much as a result.

It certainly tells him what he heard. You can’t ask for a better real world comparison than that. Putting system matching into the equation just gonna drag the thread into different subjects.

Tang
 
Why should a cored DD motor have more potential for cogging and torque ripple issues than a coreless design? We are addressing a motor spinning at less than one revolution per second, not a high speed turbine!

It matters more at low speed than at high speed actually. A cored motor has iron poled stators, which attract and repel the rotor and result in acceleration and deceleration throughout a rotation.

"Cogging torque of electrical motors is the torque due to the interaction between the permanent magnets of the rotor and the stator slots of a Permanent Magnet (PM) machine" "Cogging torque is an undesirable component for the operation of such a motor. It is especially prominent at lower speeds, with the symptom of jerkiness. Cogging torque results in torque as well as speed ripple; however, at high speed the motor moment of inertia filters out the effect of cogging torque."

A coreless motor does not have poles and therefore it has no cogging:

"What are the main advantages of this kind of motor?
•Dramatically improved acceleration and deceleration because, the iron core in usual rotors contributes to 90% of the rotor inertia. By removing this iron core, we can improve the acceleration & deceleration by an order of magnitude.
•Reduced hysteresis losses in the iron core. In a normal DC motor’s core, because the magnetic field is switching direction continuously, there are hysteresis losses. Coreless motors have significantly reduced hysteresis losses.
•No cogging. In normal DC motors, when the motor is off, and when you try rotating the motor shaft, you experience a slight resistance in motion, because the rotor is attracted by the stator. You also notice ups & downs in this resistance to motion. This is completely absent in coreless motors!! As a result of this coreless motors start rotating even at very low voltages, unlike normal motors which need a minimum voltage to start rotating. This makes these motors very well suited for control systems as they are very linear systems.
•Low ripples in torque, during operation, resulting in smoother motion.
•Possibly lower viscous losses (because of the very smooth rotor shape)
"
 
I spoke to the guyser, who is the person at whose place I heard the sp10mk2 and started my conversation with Peter. He was involved in the design and build of this Voyd back in the days and later worked for Peter Qvotrup. He said he tried the SME V and got similar results to what Peter described, and now he is using the Groovemaster with the Etsuro Urushi which I heard. He said with this combo, as well as the FR arm and the FR carts, this problem went away, so SME V is not working with the technics on his double layered slate plinth. He also said the arm rigidity matters and he uses plywood arms so that he can swap, he tried aluminium before and did not work well.

That could be...there have been reports that the SME arms are not so compatible with all kinds of TTs.
 
It matters more at low speed than at high speed actually. A cored motor has iron poled stators, which attract and repel the rotor and result in acceleration and deceleration throughout a rotation.

"Cogging torque of electrical motors is the torque due to the interaction between the permanent magnets of the rotor and the stator slots of a Permanent Magnet (PM) machine" "Cogging torque is an undesirable component for the operation of such a motor. It is especially prominent at lower speeds, with the symptom of jerkiness. Cogging torque results in torque as well as speed ripple; however, at high speed the motor moment of inertia filters out the effect of cogging torque."

A coreless motor does not have poles and therefore it has no cogging:

"What are the main advantages of this kind of motor?
•Dramatically improved acceleration and deceleration because, the iron core in usual rotors contributes to 90% of the rotor inertia. By removing this iron core, we can improve the acceleration & deceleration by an order of magnitude.
•Reduced hysteresis losses in the iron core. In a normal DC motor’s core, because the magnetic field is switching direction continuously, there are hysteresis losses. Coreless motors have significantly reduced hysteresis losses.
•No cogging. In normal DC motors, when the motor is off, and when you try rotating the motor shaft, you experience a slight resistance in motion, because the rotor is attracted by the stator. You also notice ups & downs in this resistance to motion. This is completely absent in coreless motors!! As a result of this coreless motors start rotating even at very low voltages, unlike normal motors which need a minimum voltage to start rotating. This makes these motors very well suited for control systems as they are very linear systems.
•Low ripples in torque, during operation, resulting in smoother motion.
•Possibly lower viscous losses (because of the very smooth rotor shape)
"

You are quoting Wikipedia on the definition of cogging torque, that applies to general electric motors and generalizing on the problems of general purpose brushed motors. A brushless cored motor, such as used in DD turntable, can easily be cog free - it depends on the controller. People used to stop the platter and then slowly move it to show the cogging - a ridiculous experience, as the control systems responsible for uniform torque only work at the operational speeds.

And yes, I know since long the numerous advantages of coreless motors, I do not need google searching. My question is weather they are really relevant and indispensable to DD turntables. IMHO they are only one more possibility.
 
Btw Perart1 who in the 80s used to own a Spundlabds system and then a Cello system and whose place Roy Gregory used to use as a reference room, owned both the Goldmund Studio and the Reference. He was an expert here on setting up the T3f and said that the Studio was extremely close to the Reference in SQ. He is probably reading this so he can add. But the point is the cost difference between them is huge, the SQ is not.
 
You are quoting Wikipedia on the definition of cogging torque, that applies to general electric motors and generalizing on the problems of general purpose brushed motors. A brushless cored motor, such as used in DD turntable, can easily be cog free - it depends on the controller. People used to stop the platter and then slowly move it to show the cogging - a ridiculous experience, as the control systems responsible for uniform torque only work at the operational speeds.

And yes, I know since long the numerous advantages of coreless motors, I do not need google searching. My question is weather they are really relevant and indispensable to DD turntables. IMHO they are only one more possibility.

Cogging is a function of a motor having an iron core and not whether it is brushless or not. I chose the Wikipedia definition because it is simple and still accurate.

A brushless DC motor, which is really an AC motor, will be pretty smooth with sinusoidal commutation but still will cog at low speeds. At higher speeds they make good motors for belt or maybe rim drives because they are smoother than a normal AC motor and more speed stable than a brushed DC motor (they still need feedback control). Also they have good torque...a coreless motors main weakness.

As to necessity, most of the top Japanese DD TT makers at the end went this direction. i think a lot of tape decks are also having motors of this type. To my knowledge only Kenwood though had a coreless and slotless motor in their TTs.

Interestingly, the Caliburn, although belt drive also used a coreless/slotless motor. It was very expensive and I think the Rockport DD had a similar kind of motor.

What the Japanese did then you only find now only in ultra high end today.

So, it seems that when one decides to invest in a great motor (the literal heart of a TT) that often a good result comes out.
 
Keith, I’ve often thought about this.
We evolve our sound preferences in different ways, choose gear and gear directions that “speak” to us in a certain way.
And then fashion our system moulding to enhance or counterbalance those directions.
So Peter has gone for maybe a slightly warmer, more naturally fluid sound w his SME 30, that works well with a more revealing SS amp/neutral spkr.
Albert has gone for a more forensic, detail mining SP10 Mk3, that works well counterbalanced by a warmer, more forgiving tube amp chain.
I my case, I’ve got a very full blooded, tonally dense sound, and the last thing I need is a woolly sounding belt drive, or something overly romantic. I’m best off with my fast, dynamic, start/stop rim drive/air arm.
I’m not sure if Peter’s SP10 v SME comparisons will tell him much as a result.

Marc - well put... and I suspect unconscious / subconscious elements of cognition ...shape / influence our perception
 
BMCG, thanks.
I do think I may be right, and I’m guilty of it myself.
I’ve often thought I ought to start a thread entitled “my £70k sound system...and the £150k tone control spent via room, power, cables, supports”.
Or “how I fell in love with a tt or dac...and spent many multiples of the amount making sure it was complemented well”.
 
It makes sense that the SME 30/12 with 12 inch arm and lower compliance cartridge would sound smoother than 30/2. That's kind of what you go for with a 12 inch arm.

The brighter sound of the 30/2 seemed to be a taste of Alistair-Aikman. I have not been a fan of the 30/2 screwing clamping system, which is designed to bend the edges of the record down so that the periphery has the heaviest contact and the center is elevated on a washer. Records have different thicknesses and stiffness, from potato chip to heavy and unyielding, so the screw down system can fracture center holes and does not have a uniform result on all records, though the tendency of the screw down clamping system is to move the resonance toward the upper midrange and give the bright sound that some critics note in the SME 30/2.

Since using a heavy passive clamp and a mat, the same 30/2 now has a much more mellifluous sound without losing detail. It sounds more like the classic mass loaded turntable.
 
How would you describe the quality of sound in David's system without comparison? Does it have authority, good bass and mid bass and lower mids, resolution on tuttis? And it's not hardening out the tops or glassing them over?

I have not heard David's system in a long time. There have been changes with cables and upgrades from the manufacturer. My overall impression is one of inconsistency. It has sounded very good, extended and well balanced. But it has also sounded very aggressive or restricted. I could say the same thing about any of the regular systems I hear: Madfloyd, Ack, Al M. It depends on what gear is in at the time, and in some cases, whether the latest mod is working. David's system has had authority, good bass, mid bass and lower mids, but they have also sounded bloated at times. Again, it depends. I have also heard good top end, but also a slightly glassy or mechanical sound. I can not speak to resolution on tuttis. I think David would admit that the system is a bit unsettled and a work in progress. It has demonstrated its potential but I have not heard it lately.

David should answer your question, or perhaps Al M. because they have both heard it more recently.
 
I am not convinced that Technics had the best technology with regard to either motors or speed control from the classic Japanese decks. All of the issues that Peter describes with the SP10 simply are not there with my Yamaha GT-2000, which does three things differently from the Technics. 1) The motor is coreless and on the SP10mk3 I don't think it was, so you have potential cogging and torque ripple issues, 2) It uses a bi-directional servo, developed by JVC, that eliminated the hunting you are referring to and 3) They used a high mass platter (6Kg) to give rotational inertial stability in addition to the superior servo control. Kenwood had a similar approach (better motor even) with the L07-D.

I don't have any glare or etch and in fact a lot of people who have heard my analog cannot believe how clear and transparent and natural the sound is...particularly when you consider I use an inexpensive cartridge.

I have not heard the SP10 mK3 (only a MkI and various DJ SP-1200s) but in the lesser models from Technics I have heard similar sounds to what Peter describes.

If I was going to go with a vintage Japanese table I would look into the ones with the most advanced control systems and motors of that time:
Exclusive P3
Yamaha GT-2000 and 2000X
JVC- TT101 (replinthed into something better as it was a broadcast motor)
Kenwood L07-D (with Mu-metal bonded to the bottom of hte platter so that the magnetic levitation system doesn't interfere with the cartridge...slight mod to take it to the level it deserves)
Denon 308 broadcast TT, Also, DP75M and DP6000/5000 drives can be very good.
Nakamichi TX-1000 and Dragon (both were sophisticated in different ways and have good motors/arms)
Kenwood KP9010 and others with CLFS system (for low budget money)
Goldmund Studio (JVC motor, good , control system unknown...)

Actually all of these are low budget money compared to a lot of modern high end tables. I personally have always thought the Technics tables were somewhat overrated.

However, a friend of mine had a SME 20/2 (I think that was the model) with long arm (312 I think) and we noted that its speed was not particularly stable, it was running slow at first, we adjusted it then when a record was playing it visibly was fluctuating (with Allnic Speednic that I have).

Bottom line is that there were a lot of DD turntables made that are not really worthy but some are and some are hyped but turn out to be flawed...perhaps the SP10 Mk3 is one of those...it is claimed to be one of the best but I am not sure based on what. I know though that the Yamaha GT-2000 sounds dynamic, authortiative, flowing and utterly transparent. I hear maximum contrast in my recordings...without aggression or fatigue (I can listen hours and hours without feeling the least bit tired). Another friend has a Luxman DD (PD-444) that was engineered by Micro...it is not as good as the Yammy...he also had lesser technics and Denons...not the same planet really. The KP990 and 9010 are a really good value at < $1000 and I don't hear the problems with them that is described here about the SP10mK3. Coreless, slotless motors and advanced servo will help a lot there.

Here’s a great DD based on the Denon 308 broadcast table.135EE423-5B64-4587-8A85-BB5FEB02F9E4.jpg7D30B6A5-596B-45A4-9BFA-E9DECD72A281.jpg0F9BA68C-B893-4A7F-8012-74872702DA70.jpeg
 
Cogging is a function of a motor having an iron core and not whether it is brushless or not. I chose the Wikipedia definition because it is simple and still accurate.

A brushless DC motor, which is really an AC motor, will be pretty smooth with sinusoidal commutation but still will cog at low speeds. At higher speeds they make good motors for belt or maybe rim drives because they are smoother than a normal AC motor and more speed stable than a brushed DC motor (they still need feedback control). Also they have good torque...a coreless motors main weakness.

As to necessity, most of the top Japanese DD TT makers at the end went this direction. i think a lot of tape decks are also having motors of this type. To my knowledge only Kenwood though had a coreless and slotless motor in their TTs.

Interestingly, the Caliburn, although belt drive also used a coreless/slotless motor. It was very expensive and I think the Rockport DD had a similar kind of motor.

What the Japanese did then you only find now only in ultra high end today.

So, it seems that when one decides to invest in a great motor (the literal heart of a TT) that often a good result comes out.

Sorry, you are overlooking the issue and most people mix different aspects relevant to motor performance. Cogging as referred in the wikipedia is a consequence of the variable magnetic field driving the magnetic stator non uniformly. This magnetic field is created varying the currents in the coils of motor in a way that the moving field ahead of the stator looks constant. This field is created by the vectorial sum of the fields created by each set of coils. Since long manufacturers know how to overcome this situation using optimized geometries of the core and optimized driving of the coils. Nowadays even step motors can be driven at low speeds with uniform torque using digital controllers. Twenty years ago I used a brushless 5 phase motor driven by synthesized waveforms that was extremely smooth down to one revolution per minute.

The other "cogging" people often refer is that due to the need to perform correction of speed - manufacturers claim to use algorithms to perform this correction in non audible way independently of having a core or being coreless.

The physics of electrical motors is the same for motors with a core or coreless. Hysteresis of core motors is not relevant for low power, low speed motors. But surely different approaches must be considered for the drivers.

People should remember the famous VMS66 and VMS70 Newmann lathes, that cut most of their precious Decca's recordings, used a Technics direct drive motor with large cores ...

In the end, the real judge in this hobby is our preference.
 
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I spoke to the guyser, who is the person at whose place I heard the sp10mk2 and started my conversation with Peter. He was involved in the design and build of this Voyd back in the days and later worked for Peter Qvotrup. He said he tried the SME V and got similar results to what Peter described, and now he is using the Groovemaster with the Etsuro Urushi which I heard. He said with this combo, as well as the FR arm and the FR carts, this problem went away, so SME V is not working with the technics on his double layered slate plinth. He also said the arm rigidity matters and he uses plywood arms so that he can swap, he tried aluminium before and did not work well.

The arm mounting material seems to affect the performance of different tonearms in different ways. I'm not sure there'd be one perfect material used for mounting the arm that would give optimum performance with all arms or all plinth/chassis designs.

With regard to DD motor systems I'm not convinced that maximum torque & heavy/active electronic control is the answer either.

What we need is a falling weight system that will run for 25+ minutes & no cogging etc to worry about!
 
Sorry, you are overlooking the issue and most people mix different aspects relevant to motor performance. Cogging as referred in the wikipedia is a consequence of the variable magnetic field driving the magnetic stator non uniformly. This magnetic field is created varying the currents in the coils of motor in a way that the moving field ahead of the stator looks constant. This field is created by the vectorial sum of the fields created by each set of coils. Since long manufacturers know how to overcome this situation using optimized geometries of the core and optimized driving of the coils. Nowadays even step motors can be driven at low speeds with uniform torque using digital controllers. Twenty years ago I used a brushless 5 phase motor driven by synthesized waveforms that was extremely smooth down to one revolution per minute.

The other "cogging" people often refer is that due to the need to perform correction of speed - manufacturers claim to use algorithms to perform this correction in non audible way independently of having a core or being coreless.

The physics of electrical motors is the same for motors with a core or coreless. Hysteresis of core motors is not relevant for low power, low speed motors. But surely different approaches must be considered for the drivers.

People should remember the famous VMS66 and VMS70 Newmann lathes, that cut most of their precious Decca's recordings, used a Technics direct drive motor with large cores ...

In the end, the real judge in this hobby is our preference.

What does "non-audible" minimization of cogging mean to you? If we can hear down to picoseconds in jitter, what makes you think residual micro speed fluctuations in analog are not audible?

Don't start adding alternative definitions to something that is clearly defined. Yes, there are tricks that can be done with electrical commutation to minimize the effects but the reality is physics and attraction/repulsion from the poles of an iron core motor causes torque and speed variation. The physics is not exactly the same between a core and coreless motor.

Your motor example might have felt smooth but if it was a cored motor it still had cogging.

"Absence of cogging (torque ripple) is another benefit critical for many applications.* In a conventional cored motor the rotor has a tendency to assume a certain position due to the uneven reluctance of the slot wound laminated iron rotor. Because the ironless motors have no core, the torque is more evenly distributed during any position of the rotor. The rotor can be positioned more accurately and the motion at low speed is much smoother."

"These factors bring some distinct advantages over a conventional iron core motor.
No cogging torque and smooth rotation even at low speeds
Low vibration and low noise operation
Linear speed/torque characteristic’s so the motor speed and torque is easily controlled
Efficiency. The motors are highly efficient at 90%. The motor does not have to break down the magnetic fields. The winding can almost fill the air gap between the magnet and its magnetic return
As the motors don’t have an iron core, the coil and the magnetic field of the stator is not affected by saturation effects in the magnetic field. This means stronger, more powerful magnets can be used. Many of the ironless rotor motors are using rare earth magnets to maximise performance and size
The motor winding has a very low inertia as there is no iron core to accelerate. The motor can accelerate and decelerate to full speed in milliseconds, offering very high speed performance."

THese are from current news articles and motor vendors, which make both types of motor, and show clearly that the advantages of which I speak are not some fantasy imagined. Compensate all you want but to truly eliminate cogging and torque ripple the motor has to be coreless.
 

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