Vintage DD turntables. Are we living dangerously?

10-28-15: Halcro
Dover has comprehension problems (as well as others) with both my statements and those of Markus who designed the Feickert software.
The spikes in the generated sinewave are NOT "speed corrections generated by turntable error correction".

Halcro, read my post again - I wrote

Richardkrebs argued that the spikes were speed corrections generated by the TT error correction, but they could be caused by many things, all we know is that they are speed deviations.

The statement you ascribe to me was an argument put forward by by Richardkrebs. The second half of my sentence states clearly that my view does not agree with this notion. It is not I that has a comprehension problem.

10-28-15: Halcro
They are simply part of the software program to compensate for non-centricity of the test record and the effect it has on the steady-state 3150Hz test tone.

That statement is not correct. That is not what Markus says. Markus says quite clearly

That's what the spikes are coming from: it's a superposition of eccentricity and "real" WOW and flutter.

In engineering "superposition" is the overlapping of waves.
It is very simple - the raw data graphs are the sine wave generated by eccentricity (a) PLUS the wow and flutter ( speed deviations ) (b). The software uses a notch filter to remove the sine wave generated by eccentricity.
In a nutshell the deviations from a pure sine wave ( the spiky aberrations in the raw data graph ) are the wow and flutter as Markus says..

To verify this I went to the Adjust+ website and downloaded their manual. On page 37

Please note: most vinyl records are not perfectly centered. You will often see periodical fluctuations of speed at an interval of 1.8 seconds. This is exactly the time for one revolution at 331/3 RPM. In order to mask these effects, the recorded data is filtered using a steep 0.55Hz notch filter (results beneath "Filtered at 0.55Hz"). But please bear in mind that problems with the turntable bearing probably may also cause similar fluctuation patterns at 0.55Hz. These are also attenuated by the notch filter. Both values – filtered and unfiltered - are displayed.

This extract from the manual confirms that the unfiltered graphs are a summation of both the wow & flutter due to eccentricity and the wow and flutter to to the playback system ( TT/arm/cartridge ).

Guess what - in my previous post I stated if a TT had a fault that resulted in a regular speed deviation, like a faulty bearing, this would be assumed to be eccentricity and not reported in the filtered graph. The manual confirms this.

Lewm, I do not intend to be condescending, but where errors have been made they should be corrected.

Sorry Dover,
I did mis-read your Post.

Halcro, you're a gentleman. Thanks.

Now that Dover and Halcro seem to have made up. Can we all agree that the spikes in the sine waves from the raw data are actually showing speed changes, W&F?
Secondly, as a family, TTs with tight speed correction tend to show greater aggressiveness in said speed changes?

And the winner is .....

Belt drive Onedof turntable.

Richard - one final correction.
Halcro keeps posting the VPI Direct Drive raw graph.

10-16-15: Halcro
Here is the real time analogue print-out of the actual sinewave produced by the VPI Direct whilst tracking the 3150 Hz Test Tone.

Unfortunately the raw graph Halcro posts is in fact the Onedof turntable.

Here is the link to the original graphs -
VPI Direct & Onedof raw data graphs
Figure 2 is the VPI Direct raw data graph.
Figure 3 is the Onedof raw data graph.

Interesting to note that the smoothest raw data graph by a substantial margin is the Onedof TT with stretchy rubber belt drive and high mass platter.

Fremers testing and listening notes that the Onedof and Caliburn turntables have similar absolute results, but different shaped graphs They sound substantially different in character, perhaps the raw data graphs go partly to explain it. This of course is conjecture only.