Andy Kim - Needle Clinic

Neither, Bif. It's the kind of toast that Jack Nicholson told Karen Black to put between her knees in 5 Easy Pieces.

Ha ha. I remember that. Jeez ... we are old farts.

Bif,

I can't speak for Lyra, but some stylus profiles do maintain a useable shape without serious sonic degradation longer than other shapes.

The worst case would be a conical stylus (which has a spherical cross section across the groove contact points). Even new, such profiles have limited HF extension and detail retrieval, since a contact diameter equal to the width across an LP groove is many times larger than the radii of HF's and lower level details. These "fat" styli can't trace shorter wavelengths and slur right over them. Worse, with every bit of stylus wear, this contract radius grows progressively larger. The sonics of a a conical stylus, limited to begin with, deteriorate steadily from hour 1 of play and constantly thereafter. This is exacerbated by the fact that, when new, all pressure is concentrated on two single points of contact, so wear from friction will be faster than on styli that have vertically longer contact surfaces.

Elliptical styli are better. They have shorter contact radii (in cross section) but longer contact surfaces (vertically). Their wear from friction will be slower and the resulting sonic deterioration less.

Better still are micro-ridge styli, as used by Lyra, ZYX and others in higher end models. The cross section of a microridge stylus looks something like a football with a tiny rod poking out at each end (the ridges). These ridges, which is what the stylus rides on in the groove, have a very small diameter, as small as 3 microns. As they wear down, the shape of the remaining portion of the ridge remains... wait for it... UNCHANGED! Those 3 micron contact radii are maintained until the ridges are entirely worn away. IOW... virtually NO sonic degradation. Further, the ridges are parallel to the groovewalls, making a very long contact surface (vertically). Friction is thus spread over more diamond surface, reducing the rate of wear.

This, by the way, explains the high sensitivity to SRA adjustment of micro-ridge styli, whereas conical styli are almost entirely indifferent to SRA.

So... am I surprised that your Kleos shows so litte wear? Not at all. Enjoy!

01-20-14: Bifwynne
Ha ha. I remember that. Jeez ... we are old farts.

I saw the film back in the day also, but I DON'T remember that. Maybe that's also a sign of getting old :-)

Best,
-- Al

He told her to hold the chicken salad, not the toast; it was the toast he wanted. Just fyi.