Vintage DD turntables. Are we living dangerously?

Hiho et el
I feel that I need to put my two cents worth in on the subject of cored and cordless motors. Some one has to act as a champion for the Technics line. I should also state that I have a commercial interest in the subject, so feel free to discount entirely what I am about to say....
My take on the subject is not between cordless and cored but high torque relative to the platters moment of inertia and low torque relative to same, coupled with the feedback design.
In other words the motors grip on the platter. It's "responsiveness". The Kenwood and JVCs live in the low responsiveness camp. The technics SP 10 range are firmly in the high responsiveness camp.

The SP 10 range in standard from is noisy, not in the conventional sense but noise which is a function of the music being played. There is also a tension, stress if you will, to the presentation and a greyness that over time is downright irritating.
But these faults are not intrinsic in their design, rather it is in their build. These are two completely different things.
I want drive and punch when I am listening to popular music but I want finesse and nuance when I am listening to my favourite genire, baroque.
I listen to music to connect and feel an emotional response. To feel the joy of discovery when the violinist bends the note just..so.
I want it all.

I could not live with a standard SP10 MK 2 or 3. I don't have to, but I very happily live with my worked SP10 Mk 3.

Cheers.

Regards, Lewm: Please re-read. Prominent mention of servo systems incorporated in the discussed JVC TTs. Also an acknowledgment that a correction was made to a hurried and unsupported comment. Would you kindly put your dog back under the porch?

Hiho: It's good to see that you actually viewed the Pio. links. The mention of a coreless drive in each of those links relating to the Exclusive series TTs should answer an earlier question. Their inclusion was intentional.

As to the specs given, it would seem likely that both manufacturers measured at least ONE unit that spec'ed as quoted. It would be interesting if anyone could provide contradictory figures.

Ya'll carry on &

Peace.

Richardkrebs, I agree with you on many points especially about torque. And I'm glad that you are able to enjoy a modified version of the Technics. I just wanted to add that the higher torque the higher cogging and it's a challenge to increase one without increasing the other. Your unit seems to overcome the sound that includes "a tension, stress if you will, to the presentation and a greyness that over time is downright irritating." Well said! I guess coreless motor offers a good compromise for me. Does that make me belong in the "low responsiveness camp"? Can I bring some Clash records for a spin? :)

I'm sorry that I sounded rather negative on the Technics line. I actually have fond memory of the SP10mk2 and, who knows, might even revisit it one day.


Happy listening!

Hiho
Thank you for your considered response.

Re the contentious subject of cogging.
Coreless motors cog, as accidentally powering up a Goldmund Studio without its platter, clearly demonstrated. ( JVC 4 pole, 2 phase, coreless motor). It was a dumb thing to do, but informative never the less.

The problem that you rightly ascribe to the SP range is not IMO cogging.
It is way too high in frequency to be so. The motors have 15 stator poles, don't know how many mag poles, but some higher number.
Making around the mid 200 HZ of power pulses per revolution. But they are 3 phase motors, each phase separated by 120 degrees. The sinusoid supplied phases slide into each other, improving linearity considerably, so "power pulse" would seem to be the wrong term to use.
The SP10s higher pole and phase count than a number of coreless DD motors, would imply, for a given output torque, lower amplitude but higher frequency cogging.
( The motor only delivers the torque asked of it under the load conditions at that moment in time). If it delivered higher torque than the load demand, the platter would accelerate.
I hear the problem in a standard SP10 in the kHz range. This is a feedback speed sense issue and is not intrinsic in the motors architecture and any cogging that it may produce.
It can be fixed.

Thanks for elaborating, Richard. I am learning a lot about motor. Would you say the irritating "greyness" from the Technics is due to this high frequency "pulse" created by the feedback network? Can the remedy be applied to other brands of turntables?

Quite honestly, I don't really care what kind of motor is used in a turntable as long as it does not contribute that negative sound quality you mentioned. That jittery sound once heard is easily recognized but hard to ignore and I've been avoiding it ever since I switched to other smoother sounding tables. I'm glad there are technical people like you out there addressing the issue. It's about time to shut up the DD naysayers! :)

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