Remove your bias for better sound

Thanks very much, Doug. I was hoping you would bring your expertise to bear on this.

However, although my experience is limited to relatively high compliance moving magnet and moving iron cartridges, my observations have been inconsistent with your first two paragraphs. Every time I have installed a cartridge, in most cases using the Magnepan Unitrac tonearm I have had since the 1980's, I can easily vary cantilever deflection, as viewed from the front of the cartridge while the stylus is in the groove of a rotating record, both to the left (with excessive anti-skating force applied), and to the right (with little or no anti-skating force applied). This is all with respect to the angle of the cantilever when the stylus is lifted off of the record, which is nominally straight ahead.

With too little anti-skating force applied, the effect is as if skating force is acting on the tonearm, rather than on the stylus.

And what I have observed has nothing to do with the suspension taking a "set." The deflection I have seen as anti-skating force is adjusted occurs immediately and repeatably, in either direction, and occurs only when the stylus is in the groove of a rotating record.

Deflection of the cantilever could only occur if the tonearm resisted the inward pull of the groove. An arm with zero A/S applied furnishes almost no resistance to the inward path the stylus wants to follow.

I see what you are saying. Perhaps the key to reconciling all of this is how close to zero "almost no resistance" is, for the particular arm? With cartridge compliance also presumably being a factor. Although an explanation based on bearing resistance would still leave me somewhat puzzled with respect to deflection in an outward direction.

Best regards,
-- Al

This discussion reminds me of my old Thorens TD-150, no antiskating to worry about.

Most of pivot arms already have an antiskate. Try to remove the cartridge and let the arm float free. It will slowly rotate towards rest position. Applying antiskate may be necessary for the warped records or with crooked edges. I usually land the needle right on first track so don't really care about antiskate.

Al/Doug - To me Doug's logic has a flaw.
Although the stylus is being pulled inline with the cantilever, there is a resultant force on the arm itself pulling the arm toward the centre due to the cartridge offset and overhang. Now the arm also has an inertia resisting this inward force proportional to its effective mass. Therefore there is more than likely a conflict of forces on the cantilever - inward force applied from the offset & overhang versus inertia of the arm. To my mind the amount of antiskate required is that required to keep the cantilever in line with the groove. I very much doubt that this would be 0, but it would also be influenced by the horizontal compliance of the cantilever pivot.
Intuitively unipivots have lower bearing friction than traditional gimbal arms and that would reduce the antiforce required assuming the same cartridge and tonearm effective mass is the same.
Let's face it the VPI unipivots are junk anyway, they are overdamped, the leadout wires are so rigid they must be loading the horizontal movement of the arm, the pivot point is upside down in terms of acting as a mechanical diode and every one I've heard has lacked transparency and sounds slow and turgid - this might explain why no antiskate sounds superficially better on these particular arms.