INNER GROOVE DISTORTION

It appears that the compliance of your cartridge is either 22 or 28 um/nM, depending on which version of The Voice it is. Either way, those numbers are high enough that if anti-skating is significantly misadjusted you should be able to see visible deflection of the cantilever to one side or the other when viewing the cartridge head-on while it is in the groove of a rotating record, relative to its position (nominally straight ahead) when the stylus is lifted off of the record.

I suggest that you take a look at that when the stylus is near the beginning, the middle, and the end of a rotating record, preferably during musical passages having relatively low volume. Too little anti-skating force will result in cantilever deflection to the right (toward the outside of the record); too much anti-skating force will result in deflection to the left (toward the center of the record).

Hopefully you will then be able to find an amount of twist that results in minimal or no deflection at all positions on the record.

Regards,
-- Al

I have toyed with twisting the tone arm wire, in my opinion it messes with azimuth which changes as it moves across the record. Much better to have nice even loop in the wire.

I'm with millercarbon.  If the distortion is "global" (i.e., in both channels), then I doubt it's due to a lack of anti-skate per se.  Also, if you had a pronounced lack or excess of anti-skating force, you would hear the effect at the outer grooves as well as at the inner grooves. As millercarbon mentioned, too little anti-skate affects the R channel predominantly, and you would hear R channel distortion from the first second the needle hits the LP.  Too much anti-skate will do the same in the L channel.  My guess is that the movement of the tonearm is impeded by something (wiring, maybe?), as the tonearm travels toward the spindle.  That said, I do agree with others that the lack of any provision for anti-skate typical of older VPI tonearms is egregious. Check also to see whether the cue-ing device is fouling the arm wand, as the arm pivots toward the spindle.  Likewise for the counter-wt.

Yeah, I'm a Neanderthal but my inner groove distortion bugaboos magically disappeared when I started avoiding spherical & elliptical styluses in favor of the more sophisticated profiles. Even though my line contact(?) Lyra Delos stylus is seeing its age, it'll track anything.  Even my hottest 45 rpm singles.

I use a 12" unipivot arm with no anti-skate adjustment, and I have zero audible inner groove distortion.

I am using a vintage NOS Fidelity Research MC with a line contact stylus.