Vintage DD turntables. Are we living dangerously?

Henry,
"How does the cartridge know the mass of the platter....❓👀"

You mean "know" in the biblical sense? When cart suspension collapses?

I think you would agree that platter and mat, supporting surface, does make a difference. Some platters are designed to use w/o mat and your experimentation with mats indicates agreement.
IMO, these things can not be considered in isolation. Consider an extremely lightweight platter, would tend to be more easily affected by extraneous vibrations despite stability of supporting structure. What about sound pressure waves? Maximum thickness of a mat is 5-7mm? Just enough to turn the shortcomings of a light platter, to mush.

Before you get reactionary, I'm not saying your Victors have extremely light platters, but platter mass can make a difference IMO. Consider the older Goldmund Reference - servo belt drive w/35lb platter. TT101 might have better pitch stability, but better sound is a matter of opinion. I wonder what you'd think of a Reference with one of your arms mounted.
Regards,

Fleib,

When you say VTF adjuster 'lock' are you referring to the locking nut that allows the shaft to freely move up and down? There is a nut that attaches the arm to the arm board. Then there is a nut that unlocks the arm shaft that would allows the shaft to freely move up and down when opened. When you 'unlock' it, hold on to the arm because it will freely fall and bottom out. You use that one to get the working end of the cartridge into the 'general' VTA area. Once both of those nuts are locked into place, then you can use the 'numbered' VTA adjuster +/- thumb wheel device to fine tune VTA.
To do the initial set up, I set the +/- thumb wheel in the center of its +/- range. There are arrows to define this position. Then loosen the locking nut while holding onto the arm so it doesn't drop down freely, then roughly position the arm where I think it should go, lock the nut, the do the final VTA settings. Once you have done this a couple of times, you kind of get the feel for where the shaft should be located when you lock the nut. If it was set (locked), with the arm too low, you will be forced to use only one end of the
+/- scale. Too high, you will be forced to use the other end of the scale. I shoot for a general 'center' position of the +/- scale. I shoot for that position mainly because of all the different height cartridges that I have.
Regards,
Don

Halcro.
In the manual of the ET2 Bruce Thigpen claims that a pivoted arm contributes to wow and flutter due to its geometry.

The TT-101 has exceptional figures in this area.
Since you have a rig with 3 arms, it would be interesting to run 3 consecutive tests of say 1 minute each with the three arms. This to to see if there is any difference. Each arm has different geometry, so if Bruce is correct, we may expect to see a difference between the three readings.

Purely for academic interest.

Technics SP10 Mk3

No affiliation with listing party but thought you guys would be interested

Good Listening

Peter

If anyone was interested in an SP10 Mk3, this one may be better value as it includes tonearm and base...