Turntable speed accuracy

what do you mean with this? that Paul and you listened to two TTs bis a bis with similar tonearm/cartridges at the same sessions/comparisons?

Fair question, Raul.

One TT, one tonearm, one cartridge, everything identical except the drive systems. We were comparing our tweaked BD to the (then new) Teres rim drive. Switching from one drive to the other took < 30 seconds so it was easy to compare, far easier than comparing cartridges or tonearms.

Result: we kept our BD.

FWIW, most who made the same comparison on their tables preferred the rim drive. However, those people weren't using our belt tweak because we hadn't published it yet, so their BD wasn't performing like ours. The two people to whom I provided tweaked belts also preferred the BD to the rim drive.

Implementation, implementation, implementation. :)

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Tdaudio,
The main problem turned out to be intermittent failures in the motor brushes. Very difficult to diagnose. After months of experimentation/verification, Teres found that gold brushes eliminated the problem and performed for the long haul. Ours is still working fine, quite a few years on.

Secondarily, Teres tightened the correction threshhold of the motor controller by one order of magnitude. Our platter speed now drifts from 33.33 (45) rpm just 10% as much as it used to before the controller alters voltage to the (DC) motor.

This improvement was visible with a good strobe if you watched for some time, but not really audible to me. One would need absolute pitch sensitivity to hear it.

Dougdeacon: "Implementation, implementation, implementation. :)"

I love it when I see people doing experiment like that.

My friend owns one of the earliest version of Teres turntable before it went commercial. His motor failed couple years ago so I sent him a Papst motor salvaged from the Empire 208 with pulley diameter slightly tweaked to get accurate speed. It worked well and liked the sound and used it for a more than a year. I suggested him to try driving the Teres platter with a Technics SL-M3 direct-drive turntable via VHS tape. After some tweaks he liked it even better than the Empire that it's quieter and "overall sound wise, image is focused and sharp, more forceful with muscle, very nice." Of course, the downside is that the whole set up takes up much bigger space.

Yes, it is indeed quite easy to tell the difference when you only change the drive system. People should try something like this with a belt drive table just to get an idea how much the sound can change with a different motor. It's all reversible so it's harmless. Try it. You might like it. :-)

_______

Dear Dertonarm, Dear Syntax,

You have " a schöne Rücken"

best @ fun only

Dear Thuchan, For at least someone who looks even better
than 'us' (the Connery twins) a real suprise to show off with his behind.

Regards,

I suggested him to try driving the Teres platter with a Technics SL-M3 direct-drive turntable via VHS tape.

Sounds like an interesting idea, he gets the speed lock of the DD plus the high mass and resonance sinking of the Teres platter, plinth and bearing.

He might get better results with the drive tape we developed. Compared with VHS tape it's less slippery, less elastic and much more resistant to stretching or misforming in any direction. Far better performeer than VHS tape on our TT. Check out this thread.