New Schroeder linear tonearm, any thoughts?

Hello Royaloak,
The reason for the suggested undercompensation is the usually higher than acceptable sidethrust on the cantilever, caused by an antiskating mechanism. While the force excerted by the stylus/diamond on both groove walls may be equalized, it causes a permanent cantilever displacement( since the antiskating acts on the arm, not the diamond itself), resulting in a non linear behaviour.
Imagine a speaker being exposed to a certain amount of a DC voltage. The null position of the speaker(where it rests when no signal is present) will have moved forward or backward, depending upon the polarity of said DC voltage. The maximum cone displacement is reached sooner in one direction, it takes a different amount of force to move it forward vs. moving it backward.
Same for a cantilever that has a conventional suspension, dynamic gradation is foreshortened and the resolution of microdetail(what happens around the Null point) diminished.
If one is to reduce the skating compensation to zero, the non linearities caused by non-equal pressure of the diamond on the groove walls will have a larger influence, so zero antiskating isn't the answer either(imho).
And I have not even touched the issue of the coil position against the magnetic circuit when a preload is present. Not as severe an issue and highly generator design dependent, but...

As said in the manual of my arms, my suggestion is a starting point, not an absolute(ly perfect) setting. If your method yields better results, - or results you like better, then, by all means, go by that!

All the best,

Frank

Halcro, it is interesting that the Phantom did not do well with MM cart's. I have read that before.

IMO, you can not make any solid conclusions about wiring, without testing it out on the same tonearm. Otherwise the differences you hear, or don't hear, could be caused by the arms themselves. Not the wiring.

Why would the Phantom fall short with MM cartridges? At first glance, its effective mass would not be wildly different from that of the other three tonearms Halcro mentions. In fact, its effective mass is certainly lower than that of the FR66S, if not also the DaVinci. So the observation cannot be due solely to a mismatch of compliance vs effective mass. What a strange and maddening "hobby" this is. It makes you want to go to work for relaxation.

Ahh! The Phantom is a unipivot; the others in Halcro's stable are not. Perhaps that's the important factor. I could imagine that a low compliance cartridge might be better suited to a unipivot, compared to a high compliance one.

The Phantom is not a true unipivot. It has the Magnaglide stabilizer. I don't have much experience with a MM on a unipivot arm. So I can not confirm, nor deny whether that is a factor. Could be though.