Record Damage and Conical and Shibata Styluses

The conical and elliptical styli both touch the groove wall just at one point on each side (wall) of the groove ("the area of the above mentioned contact surface figure becomes small") The only difference is that the conical stylus rides higher in the groove than the elliptical, so the two contact points are higher up the groove wall. An elliptical stylus is made by simply taking a conical stylus and shaving a flat bevel into the front and back of the cone which makes the bottom of the stylus have the shape of one half of an ellipse. Shibata styli added additional beveling to the sides of the stylus in an attempt to achieve more contact area but could only do so in a limited way or risk shattering the diamond.

Enter the laser which permitted shaping the diamond without actually touching it. This allowed for the development of the "line contact" or "micro-ridge" stylus (same thing) which oversimplified, you can visualize as an upside-down pyramid turned 45 degrees to the groove, so that two of the opposite sloping edges touch each side (wall) of the groove in a line from top to bottom.

This provided for better retrieval of the information in the groove, as well a allowing more contact area and reducing the PSI (pounds per square inch) of pressure against the groove wall(s).

An additional benefit of the line contact stylus has to do with the playing of (old) records that had been played with only conical or elliptical styli. First, imagine a horizontal "wear line" halfway down the groove wall(s) like a layer of different colored rock halfway down the wall of the Grand Canyon. This is from the contact point of the conical or elliptical stylus on each side of the groove.

The line contact stylus, by contrast, touches the groove wall in a "line" from top to bottom of each side of the groove, JUMPING OVER the wear line from the old stylus. IT DOESN'T TOUCH THE WORN PART OF THE GROOVE, ONLY NEW VINYL! Cool, huh?

I'll never forget back around 1990 when I got my first van den Hul cartridge, and was playing some favorite records from my 60s college days. They'd been reasonably well cared for, but previously played using Shure cartridges with elliptical styli -- and they were somewhat "crackly and clicky" as you put it. Imagine my surprise when the playback with the vdH was almost noise-free! I'd been told to expect that by the fellow who sold me the cartridge, but it was really quite amazing to hear.

Stylus chatter within the goove wall can be caused by many things including stylus playback type and original cutter head geometry. Shibata also claimed that his stylus geometry would playback virgin vinyl that was untouched in previous play while using a elliptical stylus. I remember seeing and reading information for Shibata to prove this particular Point. AudioTechnica at one time had cartridges that had several replaceable stylus's ..I remember the Shibata type not being my favorite.Tom

Hi Tom, yes I have the same memory about Shibata as you do. That they never really took off, although I don't know why and never owned one. But I wondered if it might be that they were simply succeeded by the line contact type. I just can't remember the exact timeline anymore.

The patent was originally submitted on March 8 1972 and patented in November 27 1973.Now in talking to a Linn dealer from whom I purchased a Linn K18 Mark 2 cartridge second-hand,he stated quite unequivocally that this cartridge's profile was a Shibata and said he thought it's high-end was especially good.A lot of people also fondly remember this cartridge,one poster on Vinyl Asylum I think even stating that it was the best moving-magnet cartridge ever made.I have it on a second table and it outdoes a Denon 103,but that's not really broken-in.

Here is a summary of the abstract to the patent for the Shibata..the idea seems actually brilliantly simple.The Shibata stylus-"a contact surface contour of a shape which is short in the longitudinal direction of the groove and long in the depth direction"...."A portion of a conical stylus body is partitioned from the remainder of the structure by one or two planes inclined at a specific angle relative to a centerline axis passing through the vertex point of the conical stylus body"...".One or two cut faces made on the body"..."Suitable points on the two lateral sides at the lower part of the edge line part and parts in the vicinity thereof contact"-the opposed wall of a groove."These have a large radius of curvature."