Turnable database with TimeLine

It would be nice to see that in the videos, too.

You can see that with all three arms on my first TT-101 video....and you can also see and hear it on my second TT-101 video.

It is likely that the Goldmund would do well in the time line test, since it's average speed would be close to the mark.

Impossible to say this without actually testing it with the Timeline I would venture....?

Didn't Goldmund source their dd motors from JVC ?
The Studio had quite the funky plinth, pretty flimsy if I remember correctly, what was Lerne thinking about ?

Yes the Goldmund used a JVC motor.
Like, I suspect most DD designs, it is a synchronous motor. The rotor ( platter) is compelled to follow the rotating field, back slightly in phase.
Provided the controller is properly adjusted, it will rotate at the correct average speed. This is the beauty of a synchronous motor. In other words, I would be surprised if a properly designed and adjusted DD TT using a synchronous motor failed the timeline test. This assumes a stable reference frequency, quartz.
The rotor lags in phase slightly behind the rotating field. If it didn't it would produce no torque. Increase the load and this phase angle increases and the motor draws more current. But the motor then continues rotating at the same speed. This is what I observed on the scope. The motor was responding to stylus drag, literally note by note. It was not showing a problem, it was showing the motor working properly and the relative enormity of stylus drag.
For a DD drive, it has a reasonably high inertia platter but this was not enough to "push thru" these load changes.
The only way for the motor to slow down, on a continuous basis, if it's field is rotating at the correct speed, is for a massive retardation torque to be applied. This would be extremely violent as the rotor rode backwards over the poles.
Wrap a properly designed servo around this type of motor and the phase angle change with load is reduced.

Thanks for the great post, Richard. I think of a 3-phase AC synchronous motor is a cousin to a DC motor. In fact, the Victor TT101 does make +/-12VDC in its PS to supply its motor. Likewise, I thought the SP10s used DC motors. But the Denon uses a 3-phase AC motor. Whether or not all of that is correct is not my point or question. What I do wonder about are the "modern" DD turntables, such as the NVS, the Beat, and the new VPI, among others. Their adverts all claim that they've avoided the nasty [sic] effects of a servo by using a 3-phase AC synchronous motor that holds speed by virtue of the mechanism you've just described, sans any servo. At least 2 of those 3 mentioned use fairly massive platters, so it seems to me they are able to give up the servo mechanism by virtue of the mass effect afforded by their platters, much as is the case for some of the better belt-drives. But still, the platter must first slow enough to trigger the speed up commanded by the AC synchronicity. Do you have any thoughts on this?
Thanks.