Vintage DD turntables. Are we living dangerously?

Lewm,
The speed problems on my TT-101 were not caused by the Power Switch.
The Power Switch began playing up (not turning OFF) about 6 months ago....and that's when I discovered the benefits of leaving the Victor 'powered up' 24/7.
Surprisingly....when I began doing that (out of necessity).....the switch began working again but switching it OFF.....produced the fault again.
That's when I wrote about the benefits of 24/7 Power for solid state DD turntables.
My Tech replaced the switch which is activated by a gear drive which advances one click at every press of the POWER switch......however in doing so....a small glitch appeared whereby when the power switch is activated now.....the platter starts spinning immediately whereas previously one needed to press either the 33 or 45 to start the platter.
As I now keep the unit powered 'ON' 24/7....this is not an issue for me.
Another glitch since the repair is the brake function which you mentioned.
Previously when the 'STOP' button was pressed...the platter instantly stopped due to the reverse current in the drive circuit....and then reverse spun for a second before stopping. This reverse spin was due to my removal of the stock heavy rubber platter mat which I have substituted with the lightweight Victor pigskin.
Now however, when the 'STOP' button is pressed.....the platter instantly stops but reverse spins for a few seconds longer than it previously did.
I don't know whether to have this and the Power Switch issue looked into at the end of my 3 month Warranty period?

The reason I finally had to take the TT-101 to the Tech was that the digital speed read-out began indicating widely varying speeds at both 33.33 and 45 rpm.
Since the caps and soldering replacement.....this appears to be solved.

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.