Do 45 RPM records need higher anti-skate setting?

Lewm,
Check out the link to Alexandrovitch and other papers via this link.

He found that with an unmodulated groove, there was no change in friction with radius ie groove speed. With a modulated groove there was an increase in friction, and this increase increased towards the centre, despite, apparently, the reduction in groove speed.

Ct0517,
I don't get the thing in the ET manual regarding the two skating forces. Certainly there is a tiny component of skating force due to the stylus contact point and the cantilever bearing point being in different places, but as far as I am aware that is not a major consideration in terms of the overall picture. But all skating depends on overhang, because it is that which gives rise to the fact that the groove and arm pivot are not in a straight line, thus causing the forces, unlike in the ET which is a linear tracker. If it was set with overhang it would skate too.

John

John, Yes, I just misunderstood the language of your first post on Alexandrovitch. I later figured out what you meant, and there is no disagreement with our earlier conclusion.

I hate to discuss the origin of the skating force, but I love it too. Such is life. My belief is that the prime cause of the skating force is friction of the stylus in the groove coupled with the fact that the cantilever is never tangent to the groove, because of "stylus overhang". "Headshell offset angle" changes the directions of the force vector that results from this. But the net effect is a force that pulls the stylus tip inward along the arc of the tonearm. (Because the tonearm is mechanically stiff and the pivot is anchored, the only way the stylus tip can respond to the forces on it is to "skate" inward on the one permitted path.) This is how I think of it, anyway.

So the idea that a 45 rpm disc cut with greater modulation to also require slightly greater anti-skate sounds like its not that far-fetched.

Atmasphere,
It would seem so.

Lewm,
I think your take on it is right. All I would say is that rather than "headshell" offset angle, it is perhaps better to think of it as "groove" offset angle (which is what gives rise to the tracking angle error, as both the cartridge offset and headshell offsets remain constant while the groove offset angle changes, the error increasing markedly at the innermost radii, giving rise to higher skating forces there).
J
.

Ralph, Yes, but wouldn't you think that a 45 rpm version of any LP would have relatively lower groove tortuosity/modulation than the comparable 33, because the music signal is allowed more "room" at 45 rpm, per unit of time. Thus, I thought the OPs story that increasing AS helped was not consistent with the notion that groove modulation affected the skating force so as to increase it on average. If anything, I would expect a decrease in skating force, on average. That was a point i made way back up the thread.