Turnable database with TimeLine

Tony,
Maybe it isn't as obvious to some, but I hope our posts about cogging and other aspects of a turntable's design will be helpful, though. It's a lot to expect guys who aren't that interested in the mechanics of it all to understand why what they hear in a given turntable isn't exactly right, or is decidedly different from a very similar one. Hopefully, enough of the participants here are articulate enough to explain some of the things involved in ways that the casual onlooker can understand, though.

In any case, it isn't that easy to sort out all the nuances of what should be a very simple device that has the seemingly simple task of quietly spinning around.

@Lewm

In this entire thread "NOBODY" that used the timeline and "observed" the speed changes due to stylus drag came out and said they detected "ANY audible sonic changes!'

This whole tread is about drag measurements that are "NOT AUDiBLE" on well designed "high end" turntables set up with a strobe!

"Climb it and Rotate"

Don.
re your post to Lew. "Nobody has used the timeline.... and detected any audible sonic changes."
Firstly. The time line shows average speed per revolution. A TT that passes the timeline test has a "consistent average" correct speed, no more than this. We cannot see what is happening at a micro time interval level, but we can infer.
I would be surprised if anyone could detect the adjustment of this average speed back to say 33 1/3 if the TT in question showed slowing due to stylus drag. We are talking small changes in absolute frequency with this adjustment. The owners of these TT's cannot however adjust the TT's dynamic speed stability since this is intrinsic in how the TT was built and designed. This includes its power supply and controller. Of course there will be no audible changes since these owners are making no changes to the TT build, design itself.

However there is, I believe, at least one person posting here who has direct experience with the audible effects of an improvement in resistance to stylus drag and dynamic speed stability.

That poster is........you.
You reported a "huge" improvement in the VPI when using the SDS controller.
This device makes the motor run more consistently. What you heard was a platter rotating more accurately at a micro speed level. It is quite possible that its average speed with a load, did not change, so no difference would be seen with a Timeline. But you correctly reported the positive changes.
It would make logical sense that a motor which runs more consistently would be better able to respond to and minimise speed changes due to a dynamic load, such as that caused by stylus drag. So it would further be logical that the VPI would show greater resistance to speed sag when lowering the stylus (no load, with load) and we would likely see an improvement if this test was done with the Timeline.
So we can say that you are a champion of a design that reduces speed changes due to stylus drag.

Tony, This is an example of playing a very eccentric record:
http://www.youtube.com/watch?v=H_GG65tMxOs

You see the saddle swaying to and fro smoothly due to eccentricity. If you look closely enough (sorry my stone-aged video quality, well I´m not into videos really lol) you may notice the stylus stays perfectly stationary relative to the cartridge body. So the "wow" is practically caused only by the eccentricity of the record. The music sounds still very enjoyable. In this case the Salvation direct rim motor implementation works very nicely. If we have very sophisticated analog techniques, records can sound very nice despite of platter or/and record eccentricities... and slight warps.

My point is that knowing about the specific motor is useful when making these Timeline comparisons because what you see isn't always what you actually get.

I know this is true….and I apologise to Tonywinsc if I appeared dismissive of his valuable contributions here…..but at no time was ‘cogging’ mentioned till I did so in regards to the video showing this phenomenon with the Timeline on the Micro Seiki RX-5000 string-drive turntable. This is one of the drawbacks of using string or thread drive turntables as there is no ‘filter’ to the motor’s cogging like there is with flexible rubber belt drives.
For an inflexible thread or string drive turntable to work well….the motor needs to be virtually ‘cogless’ like that of the Caliburn as Mosin has mentioned.
I understand what Tonywinsc and Mosin are saying about motors and their characteristics……and I agree that it is a highly complex subject for those without the knowledge or interest.
HERE
is a Link to Peter Moncrief’s full article which asks….and answers….more questions than you ever knew existed about turntable motors?

However……this Thread is about a Video Database of turntables with and without stylus drag as demonstrated via the Sutherland Timeline.
Syntax’s video clearly demonstrates that severe motor ‘cogging’ can be seen on the Timeline laser whilst other videos posted…..show that any cogging which may exist in other motors….is not so graphically demonstrated?
Many of us have readily admitted that correct and/or consistent speed control of a turntable…is but one ingredient to determining its performance.
Many of us also agree that it is however….the primary fundamental ingredient to get right.
Speculating on the other ‘hidden’ qualities of a particular motor….which cannot be demonstrated via the Timeline or other objective repeatable tests….should be discussed on other more suitable Threads?

We are still hopefully awaiting the promised Timeline video for Mosin’s turntable….and perhaps Dover’s Final motor which appears more sophisticated than the Micro Seiki model and might demonstrate a ‘string-drive’ turntable which doesn’t suffer from cogging or ‘stylus drag’?