Natural Sound

[tima]

Yes, he did say that. But he said more too. My interpretation is that the platter pad that came with the turntable was detrimental and he wrote the plinth was not good so if anyone has heard the turntable in stock form, he wouldn’t know what the turntable was capable of sounding like.

Agreed.

 

[morricab]

I am not saying it is a bad TT, my mother owned the top model in the mid nineties, but as good as it gets, no way as good as the best. My Nakamichi Dragon CT sounded better and it was really not that good either.

Technics was not using the best motor technology back in their classic era products like the SP10 series. Those used iron cored motors that had torque ripple and they also didn’t have the most advanced control logic at the time either. The new top model from Technics is finally using a motor that is similar to a classic Kenwood L-07 from the late 70s, which is still SOTA today.
Your Dragon CT at least used a coreless/slotless motor but needed a heavier platter, plinth and better control logic to really shine.

 

[morricab]

Oh I forget Rex’s STST Motus II which is a suspended low torque DD is quite good, nice tone and flow. The suspension can sometimes cause a slight hump in mid bass like some Garrards, but in the EU is a good value relatively lower priced table.

Brinkmann and Primary Control DDs are also very good sounding modern examples.

 

[morricab]

i think many turntables can sound good, but that's not the whole story. until you hear another 'better' turntable side by side with better flow. at one point i had the Dobbins Technics SP-10 Mk2 and also the Dobbins SP-10 Mk3, and the Dobbins the Beat and the NVS all together plus the Dobbins Garrard 301.

the Beat and the NVS were another level beyond the two Technics in terms of flow. and this was an early NVS, not my later build one. and those SP-10's were objectively very very good. i know there are Richard Krebs motors for the SP-10 that are said to be 'better', but never had the chance to compare one to anything else.

so liking a turntable and it having good performance is a different thing than how it 'flows' in the larger scheme of things.....especially for DD turntables.

the new Technics SP-10 is very very good and i'm not knocking it. i've not heard one other than at a show. and not heard one with an exotic plinth either. but unless it's directly compared to higher level turntables it's hard to assume anything. i did hear the SAT XD1 at Axpona last year which uses the SP-10 as a build component and heavily modifies it. that one sounded really good in the system i heard it in. fantastic.

The motor was a huge limitation for the SP10s. It was the wrong design for what a DD needs. Huge torque, despite what many think, is not required…low/no torque ripple is vitally important. I am not at all surprised you found the more modern DD tables to be better because of this reason alone.

 

[bonzo75]

Brinkmann and Primary Control DDs are also very good sounding modern examples.

In Brinkmann I only like the balance, not the other models.

I don't have enought exposure to PC. the field coil arm seemed excellent at Mike's, I wasn't impressed with the non-FC arms. I must say all DDs look visually nice to me because of small footprint

 

[bonzo75]

The motor was a huge limitation for the SP10s. It was the wrong design for what a DD needs. Huge torque, despite what many think, is not required…low/no torque ripple is vitally important. I am not at all surprised you found the more modern DD tables to be better because of this reason alone.

STST Motus II is also low torque. Technics is the most digital of the DDs. Like Lagonda I am surprised Ralph can't hear that.

 

[microstrip]

The motor was a huge limitation for the SP10s. It was the wrong design for what a DD needs. Huge torque, despite what many think, is not required…low/no torque ripple is vitally important. I am not at all surprised you found the more modern DD tables to be better because of this reason alone.

How should we measure the torque of a direct drive when playing? Direct drive turntable turntables have dynamic torque - usually higher at start up to speed fast to normal speed, very low when they lock to correct speed and are playing. If we try to measure it by conventional means, they immediately increase torque. IMO we should not mix the start-up transient torque with drive operating torque.

 

[morricab]

How should we measure the torque of a direct drive when playing? Direct drive turntable turntables have dynamic torque - usually higher at start up to speed fast to normal speed, very low when they lock to correct speed and are playing. If we try to measure it by conventional means, they immediately increase torque. IMO we should not mix the start-up transient torque with drive operating torque.

Torque ripple is the inconsistency of the torque being applied. Under a high torque scenario, the ripple is going to negligible; however, once the platter is at “cruising speed”and the torque needed to keep the platter at that speed is low, the torque ripple will be a significant contribution to the overall torque being applied. I think this is a big contributor to the perception of dryness a lot of inferior DDs suffer from.
Another potential problem is that high torque means high acceleration potential and if control software is not carefully calibrated too sudden speed changes can occur, which some think is also responsible for negative sound side effects.
In contrast, a high mass belt drive with low torque motor simply cannot change speed quickly, which of course has its own issues.

 

[morricab]

In Brinkmann I only like the balance, not the other models.

I don't have enought exposure to PC. the field coil arm seemed excellent at Mike's, I wasn't impressed with the non-FC arms. I must say all DDs look visually nice to me because of small footprint

That’s surprising because the Brinkmann Bardo/Oasis/Taurus are low torque/high mass like STST and pretty much universally praised.

 

[bonzo75]

That’s surprising because the Brinkmann Bardo/Oasis/Taurus are low torque/high mass like STST and pretty much universally praised.

I am not saying I like it because it is low torque, just an observation I like it and it is low torque.

Maybe the suspension helps. It is adjustable so can change the sound.

 

[microstrip]

Torque ripple is the inconsistency of the torque being applied. Under a high torque scenario, the ripple is going to negligible; however, once the platter is at “cruising speed”and the torque needed to keep the platter at that speed is low, the torque ripple will be a significant contribution to the overall torque being applied. I think this is a big contributor to the perception of dryness a lot of inferior DDs suffer from.
Another potential problem is that high torque means high acceleration potential and if control software is not carefully calibrated too sudden speed changes can occur, which some think is also responsible for negative sound side effects.
In contrast, a high mass belt drive with low torque motor simply cannot change speed quickly, which of course has its own issues.

Thanks, but you did not address my main point - quantification of DD torque when the turntable is operating at normal speed. Nothing in instrumental reality seems to support your "feeling" - I am not addressing subjective perceptions, that I respect. IMO what you refer is a mix of Newton Law, poor design of control systems and audiophile myths. Other than the control system the relevant aspects are platter mass and friction.

Again, I am not addressing poor designs of DD technique, just those most audiophiles and known designers consider SOTA.

 

[morricab]

Thanks, but you did not address my main point - quantification of DD torque when the turntable is operating at normal speed. Nothing in instrumental reality seems to support your "feeling" - I am not addressing subjective perceptions, that I respect. IMO what you refer is a mix of Newton Law, poor design of control systems and audiophile myths. Other than the control system the relevant aspects are platter mass and friction.

Again, I am not addressing poor designs of DD technique, just those most audiophiles and known designers consider SOTA.

Higher Torque available will mean greater resistance to change in speed from load, but the rate of change in speed must be regulated correctly to not be audible…not so trivial to do correctly. Kenwood, for the L-07, had a very sophisticated nested set of loops with loose and tight control depending on the variations.

Welcome to the Unofficial Kenwood L-07D Direct Drive Turntable Website Motor Page

 

[morricab]

I am not saying I like it because it is low torque, just an observation I like it and it is low torque.

Maybe the suspension helps. It is adjustable so can change the sound.

I doubt the suspension has much to do with it

 

[Rexp]

Technics was not using the best motor technology back in their classic era products like the SP10 series. Those used iron cored motors that had torque ripple and they also didn’t have the most advanced control logic at the time either. The new top model from Technics is finally using a motor that is similar to a classic Kenwood L-07 from the late 70s, which is still SOTA today.
Your Dragon CT at least used a coreless/slotless motor but needed a heavier platter, plinth and better control logic to really shine.

Don't you think the Kenwood L-07 sounds typically DD mechanical in this video compared to the Thorens TD124 below it?

 

[Lagonda]

Technics was not using the best motor technology back in their classic era products like the SP10 series. Those used iron cored motors that had torque ripple and they also didn’t have the most advanced control logic at the time either. The new top model from Technics is finally using a motor that is similar to a classic Kenwood L-07 from the late 70s, which is still SOTA today.
Your Dragon CT at least used a coreless/slotless motor but needed a heavier platter, plinth and better control logic to really shine.

It also had this weird arrangement with a glass plater on top of the aluminum one, for record centering purposes. And a half-automatic arm with exchangeable arm wands, it sounded better with the Forsell Air arm i added.

 

[DasguteOhr]

If used correctly, glass doesn't sound as bad as you might think. Try two glass plates with a noise-proofing film between them. The advantage is that the surface is absolutely flat and it's easy to clean.

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[microstrip]

What I don’t quite understand is that you are doing this research to presumably guide you when choosing your new turntable. Don’t you think the results of the test you propose are going to vary depending on the design of the turntable? With the motor detached, you are looking at the bearing friction and platter mass, but also the proportions of the platter will likely matter. And some turntables might even even stop spinning before the five minute test is over. I would think the effect of stylist drag will vary, depending on the design of the turntable.

Why don’t you do the test yourself on the turntables you’re considering buying. My turntable is no longer available and so information you glean from that won’t really be relevant.

In fact, I have now new information that I find relevant. I have now got a turntable known for its SOTA bearing - the Empire 598. (rumble -90dB, wow and flutter less than .01% )

Using a strobe and chronometer I could measure the time it takes going from 33.33 to zero RPM with no belt - 1 minute and 36 seconds. A fantastic result IMO and I will explain why.

Bearing friction is a conservative force that generates work - the energy produced in the bearing by this process is released as heat. Spinning beltless the platter stops after some time because the energy stored in the platter due to its moment of inertia at 33.33 RPM is drained in the bearing. Assuming average, the power of the bearing is the energy dissipated in one second and proportional to our feeling of friction. Rotational friction is measured in newton x meter, we address dynamic friction, not the easily measurable static friction

Some more physics : the moment of inertia of a solid cylinder rotating about its central axis (longitudinal axis) is given by:

= 1/2 x x power 2 , being the angular rotational speed.

and the energy stored in a rotating cylinder with moment of inertia I is its rotational kinetic energy, given by:

= 1/2 x x power 2

Just to say that having two platters spinning at 33.33 rpm, the individual stored energy is proportional to their individual mass. Going in details, assuming a mass of 60 kg for the AS2000 and 3 kg for the Empire 598 we can say in rough that the energy stored in the AS2000 is 20 times higher than that stored in the 598. Considering that the ratio of the stopping times is approximately the same (1800 versus 96 seconds) we can say that the power of the two bearings is similar and consequently both bearings have similar friction. Surprised? I was, please check my calculus! They only address friction per se - no connection to other aspects of turntable design, manufacture or performance.

Please note that this is an approximate result - some simplifications were assumed , mass values are not exact and the 598 platter is not a cylinder. But IMO these approximations will not change the value of the estimation in a significant way.

 

[bonzo75]

Forgot to add, EMT 948 and 950 both sound poor. The 930 sounds better than both of them, more like a good value table. And the 927 is better than 930 but both are idlers, the first two are DD

 

[morricab]

Don't you think the Kenwood L-07 sounds typically DD mechanical in this video compared to the Thorens TD124 below it?

One other detail about the Kenwood that was discovered long after they were no longer made. You need to put mu metal on the underside of the platter to get really good sound. This is because the bearing is partially supported by magnetic repulsion to lessen the load on the bearing. Those magnets have been found to interfere with the cartridges and degrade the sound.

 

[morricab]

Forgot to add, EMT 948 and 950 both sound poor. The 930 sounds better than both of them, more like a good value table. And the 927 is better than 930 but both are idlers, the first two are DD

They both use high torque cored motors that are probably some kind of AC synchronous…a poor choice for a high end deck but fast for radio stations.