Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.3 alpha 4/15/85; site ubvax.UUCP Path: utzoo!linus!philabs!prls!amdimage!amdcad!cae780!ubvax!scott From: scott@ubvax.UUCP (Scott Scheiman) Newsgroups: net.audio Subject: Anti-skating Message-ID: <310@ubvax.UUCP> Date: Sun, 25-Aug-85 22:22:32 EDT Article-I.D.: ubvax.310 Posted: Sun Aug 25 22:22:32 1985 Date-Received: Fri, 30-Aug-85 00:13:38 EDT Organization: Ungermann-Bass, Inc., Santa Clara, CA Lines: 82 -- Hello, world. My first "real" posting to the net (I've been an avid reader for quite a few months now). Please bear with the length of this. At the end are some questions I'd like answers to. What this is about is a new (?) technique I developed a while back for adjusting anti-skating with traditional pivoted tonearms. I came upon the idea partly by accident and partly by analyzing just what skating is caused by, but later I realized that my technique just might be an improvement over relying on the anti-skating calibration provided by turntable manufacturers. I make this statement based on two things: 1) the amount of skating force (and therefore the anti-skating compensation needed) is a function of the amount of friction between the stylus and record, which in turn is dependent on (among other things) the shape of the stylus. My turntable's anti-skate adjustment has three scales, one for spherical, one for elliptical, and one for the newer "vertical line" type styli, but it seems to me that these scales are guesses on the manufacturer's part and that in some cases I might not be able to pick the proper scale or even that the manufacturer's guesses are "right". 2) When I checked the calibration of the vertical tracking force (controlled by a dial on the vertical tonearm pivot) against a balance, I found that the calibration of the VTF dial was off. Presumably the anti-skating dial can exhibit similar variation. My method is dynamic, and ignores any pre-set calibrations. I'm going to skip the physics lesson (it seems VERY difficult to send vector diagrams through this medium) and let you all work out yourselves whether my idea is valid or bogus. (If there is a demand, I just might try posting my analysis of skating/anti-skating!) So here it is: With a record spinning on the turntable, cue the tonearm over the record somewhere and then sight along the length of the stylus cantilever. Then alternately cue the tonearm onto the record and back up. The anti-skating is NOT adjusted correctly if you notice any apparent bending of the cantilever from straight toward you as it settles onto and leaves the record (horizontally, that is--it will, of course, be seen to "bend" vertically due to the VTF). That's all there is to it. Adjust your anti-skating until you see no horizontal bending as you cue up and down. (If it bends such that the cartridge body seems to move toward the center of the record as the tonearm settles onto the record you need more anti-skating compensation, and vice-versa.) I've used this technique for a few years now and it seems just fine. However, I once tried it on a friend's turntable and ran into a couple of problems. First, the amount of anti-skating which my method implied was necessary was beyond the range of her turntable (!). So, with the anti-skating set to its maximum, we proceeded to notice that the tonearm would be "pulled out" by the anti-skate mechanism whenever it was cued up (it couldn't be lowered to the same spot on the record). The friction of the cueing needed to keep the tonearm from going left or right was not up to this amount of anti-skating force (!!). So here are my questions: 1) I've subscribed to many of the major audio magazines for years now and I have never seen any reference to this technique. Have any of you heard of it before? 2) Does this method have validity, or have I made a mistake in my analysis somewhere? 3) Just how much difference does the precision of anti-skating compensation make, anyway? Maybe the calibration on my turntable is good enough as it is! 4) With the last two questions in mind, is this new technique good enough? It might be, for example, that the typical stylus' compliance is stiff enough that the amount of anti-skating variation needed to get a visible deflection might be much greater than the refinement I'd really need to achieve. Post answers directly to me or to the net or anywhere else you think they belong. Thanks! -- "Ribbit!" Scott Scheiman (Beam Me Up, Scotty!) Industrial Networking Inc. `/\/@\/@\/\ ..decvax!decwrl!sun!megatest!ubvax!scott 3990 Freedom Circle _\ \ - / /_ (408) 496-0969 Santa Clara, CA 95050