Remove your bias for better sound

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.

Dover,

Thanks for the alternate view... very useful insights on the competing forces at work here. I'll defer to anyone with a real understanding of physics as to how the forces net out. In anecdotal terms, I've played with zero A/S on my Triplanar for several years. My main cartridge has ~1000 hours of play under that condition and displays no cantilever deflection whatever... FWIW.

In real world use, I believe that A/S devices present a greater risk of causing (inward) cantilever deflections than the risk posed by skating forces to cause (outward) cantilever deflections. This is because the majority of A/S devices and users apply TOO MUCH FORCE.

Unless one does some fairly tedious and involved experiments one may not appreciate just how little A/S force is actually needed to achieve balanced sidewall pressures when playing real music. On my way to playing with zero A/S I experimented for months by reducing A/S to truly tiny amounts, far lower that the original design of my TriPlanar's device would permit. I replaced the metal A/S weight with rubber O-rings, each of which weighed only 1/23rd as much, and eventually played without even those, only the empty dogleg itself was applying any force.

To hear the effects of this required playing at the lower limit of VTF needed for clean tracking. That's where my cartridge plays best anyway so I was already tweaking VTF on a daily basis, sometimes by less than .01g. Having found the knife edge of trackability I began reducing A/S while playing difficult-to-track passages (real music, not test records). I was surprised to learn just how little A/S was needed to eliminate R channel breakup. As my cartridge passed 500 hours I found that essentially no A/S was needed, but even when it was the amount applied by the tonearm's supplied weight was vastly too much. I never needed more than 1/4 that much weight, even when the cartridge was new. My conclusion: the majority of users have not taken the time to experiment to this degree and are probably applying too much A/S, particularly as the A/S devices supplied with some tonearms apply too much by design.

As to sonics, I've no experience with VPI arms so won't comment on your impressions, but the sonic improvements from using zero A/S are very clearly heard on my tonearm too. As stated, I believe these improvements result from eliminating the pre-dampening of the cantilever against the suspension. Of course the audibility of this or any tweak will vary with the cartridge, the tonearm and the transparency of the entire system.

11-08-12: Dover
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.

Thanks very much, Dover. That all makes sense to me, and is consistent with the observations I described. Which would say that as anti-skating is fine tuned by ear, a visual check should also be performed to confirm that no perceptible left or right cantilever deflection occurs, as viewed from the front of the cartridge, as the stylus enters the groove of a rotating record. Perceptible deflection occurring most readily, as a result of non-optimal adjustment of anti-skating force, in the case of high cartridge compliance, low tonearm effective mass, and also, if my understanding is correct, low cartridge weight. All of which is what I happen to have, relatively speaking.

FWIW, with my Soundsmith re-tipped Grace F9E Ruby and my undamped Magnepan Unitrac unipivot arm I've settled on an anti-skating force equal to about 56% of the arm manufacturer's recommendation. I suspect that their recommendation is based on setting anti-skating force equal to tracking force, which is a ridiculous notion IME.

Doug, thanks also. The concluding sentences of your two posts above seem to sum up the bottom line -- as is usual in audio, things are system dependent.

Best regards,
-- Al

Stringreen, after removing the anti-skate device did you then use Harry's recommended "twist" to the connection wire or plug that in straight from the arm? (for non-VPI owners, this is their recommended method for all the counter force they believe is necessary)

Doug/Al - I 100% agree with Doug's comment that too much antiskate is applied in most instances. The proof is that very few cartridges have straight cantilevers after a short while. The most common mistake I've seen is people using antiskate to adjust channel imbalances in the system. The other major factor is armboards that are not level. How many people 0 balance their arm and make sure there is no drift in or out before they start. This is a simple check to ensure there is no inward or outward pressure on the cartridge from the horizontal bearings in the arm being out of level because the armboard is not level. When I recently installed a new arm I had to shim the armboard by a only few micron to ensure the arm had zero drift and the resultant decrease in antiskate required was significant - 0.5gm.