Using Test LP - curious observations

If it's such an objectively verifiable problem, why do some (and that's Harry Weisfeld included) don't hear any improvement with anti-skate applied?

It's not that we don't hear any improvement. I do. It's just that we hear many more detriments that swamp the improvement.

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The problem, as I've posted several times over the years, is that real-world A/S mechanisms apply lateral bias to the TONEARM, yet the skating force they're trying to counteract is generated at the STYLUS.

Imagine, if you like, grabbing the STYLUS with your left hand and pulling it inward (skating) whilst at the same time grabbing the TONEARM with your right hand and pulling it outward (anti-skating). This is what's actually happening with skating forces vs. anti-skating mechanisms.

It's easy to visualize that these unequally applied biases necessarily pressure the cantilever against the suspension. This pre-dampens its freedom to make excursions based on groove modulations. Result: softened micro-dynamics, slowed transients, dampening of the finest, lowest-level sounds in the groove. Sound familiar?

This is why excessive (any) A/S sounds almost exactly like excessive VTF. Both pre-dampen the cantilever against the elastic suspension, reducing its freedom.

The ideal A/S mechanism would operate like this: your left hand pulling the STYLUS inward (skating) whilst your right hand pulls the STYLUS outward with exactly the same (ever-changing) force, with zero lag time of course (anti-skating). This would avoid pre-dampening the cantilever and, if perfectly implemented, would carry no sonic penalty.

Of course no one has or ever will build an A/S mechanism based on a perfectly reactive string tied to the stylus and pulling outward. ;-) The mechanisms it's actually possible to build are necessarily imperfect, as described above, and will always carry the associated sonic penalties as well as benefits.

SirAnthony,

It isn't VPI tonearms in particular. I hear what Harry Weisfeld hears on my TriPlanar and on a Durand Talea. Audiofeil hears similar things on five of his six tonearms.

It's partly cartridge-dependent and partly a matter of how well a cartridge/tonearm combo tracks difficult passages. The new Yatra I had on my TriPlanar for a day or two also needed a scosh of A/S. OTOH, the Airy 2, Airy 3, Atmos, multiple UNIverses, a Lyra Olympos, two Benz's and two MMs all needed no A/S after 2-300 hours of break-in. It's possible the Yatra might have reached that point too (on my tonearm) but I didn't have it around long enough to be sure.

What tonearm are you using? If it's toward the lower mass end and/or if your Yatra lacks the SB weight, that would create a borderline combo for trackability that might necessitate A/S.

Dougdeacon, yes you are correct, the kW phono stage is quieter by a large margin (not even comparable) over my previous phono stage.

Dear Doug,
Thank you for your insights, your conclusions are highly plausible. At the risk of stating the obvious you will no doubt have seen cantilevers bent like a bow due to skating force (not referring to my current rig here, but past experiences BTW :)
This deformation to me suggests some stressing of the suspension. If a corrective force, albeit applied at the pivot end of the arm, renders the cantilever behaviour as straight and true as an arrow in the groove, then is it conceivable that the suspension could be LESS stressed than allowing skating force to otherwise act unhindered?

Would it be fair to say that if the cantilever looks good it is good, or is this misleading...?
Best regards...

Moonglum,

Good question:

...you will no doubt have seen cantilevers bent like a bow due to skating force

Actually, I have never seen a cantilever bent/angled due to SKATING forces and I doubt anyone else has either. Skating forces pull the stylus inward. Providing that nothing resists the inward movement of the arm, no particular stress is placed on the cantilever. Everything just follows along and no deformation occurs.

OTOH, I have seen cantilevers bent/angled from excessive ANTI-skating forces.

If an unweighted cantilever is bent/aimed INWARD then excessive A/S or defective/sticky tonearm bearings should be investigated as possible culprits. Since these both present resistance to inward tonearm movement they may deform the suspension. (Manufacturing defects or user abuse are also possibilities of course.)

If an unweighted cantilever is bent/aimed OUTWARD then a manufacturing defect or user abuse is highly likely. Skating forces, anti-skating forces or sticky tonearm bearings would not cause this.