Nsgarch, I've always thought the line contact styli have a greater contact area than the elliptical ones. Greater contact area means more friction (although the pressure/area unit is less).Dazz, sometimes Physics can be maddeningly counter-intuitive, can't it?! The amount of skating force produced is directly proportional to the friction developed between the stylus and the vinyl. Since the contact area of a conical/elliptical stylus is essentially zero, the VTF divided by zero = infinity. Therefore the skating force (in theory ;-) should also be infinity (which it isn't ;-) but the psi is still much higher than that of a line-contact stylus, which 'spreads' the VTF over a calculable area.
In addition to the contact-area-vs-friction issue is this point: assuming the SRA is properly set http://forum.audiogon.com/cgi-bin/fr.pl?eanlg&1140840022&openmine&Nsgarch&4&5&st0 a line-contact stylus will 'lock' into the groove for effortless (in theory ;-) tracing. Conical and elliptical styli kind of 'skip across the high points' of the groove modulations (I'm exaggerating for illustration ;-) which adds additional friction.
If you ever have a chance to watch an earlier model Shure MM cartridge (like a V-15 Type II) and see how much the cantilever deflects, even at one gram VTF, you'll understand where the AS = VTF standard came from.
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