Anti-skating: how to set


I'd appreciate some help on setting anti-skating on a Rega 25 and an SME V. I have no access to an oscilloscope. I do have the Cardas "Sweep" record, which has areas of blank grooves that may be intended for (among other uses) setting anti-skating force with pivoted tone arms like mine. I did set anti-skating force that way, adjusting it until the cartridge remained stationary, moving neither in nor out. Can I have any confidence that this procedure gets it right?
tom_nice
You should understand that any anti-skating force you apply will rarely be exactly the "right" amount. The spinning record pulls the stylus in a direction of a tangent to the groove at the point of the stylus. If the cartridge is restrained by the pivot of an ordinary arm, that pivot is inside the tangent and therefore does not pull directly back on the stylus. The sum of the vectors is a force toward the inside of the record, skating force, which you try to counteract with anti-skating force. The key point here is that the skating force varies with the pull on the stylus, which varies with the condition of the record, the shape of the stylus, the speed of the groove [which varies across the record], and the magnitude and frequency of the modulations of the groove. The anti-skating force is, by contrast, essentially fixed in amount [although there are ways of making it change, like using magnets]. Once you know that any amount of force will be the wrong amount a good portion of the time, you can avoid worrying about whether it is set just right. [One practical point: using a grooveless record, as some people do, is probably not a good approximation since there is probably less friction since the stylus is not in a groove. My guess is that you should apply a little more anti-skating force than the amount needed to stop skating on a blank disk.] Isn't analogue fun?
Thanks everybody. I'll look for the HFNRR test record, but won't worry too much until I get it since at least one expert (as judged by posts on other topics) thinks the blank space isn't too bad. I'll repeat what I did making sure to use blank grooves as close to the center as I can find them.
The best way I know of for setting the anti-skating is to use the Hi Fi News and Record Review test record. It's available at several different audiophile vinyl outlets (Red Trumpet, Acoustic Sounds, etc.). They have several successive tracks of a tone in stereo cut at increasingly high modulations. One simply cues up each track, listens and empirically adjusts the anti skating force until the minimum amount of force necessary to prevent audible distortion is found. When there's inadequate antiskating force it's VERY EASY to detect audible distortion. The test record can be used for several other adjustments as well, but if it only had the antiskating adjustment feature, that alone would make it worth the cost. BTW, IMHO a blank region on a record is no way to set antiskating: without grooves, it is not a true negative control.
Hi, SDCampbell,

You forgot the say HOW to set anti-skate using the blank portion of the LP. In other words, what to observe when the anti-skate is too high or too low?

I personally use the Shure V15 LP myself. However, since the LP was poorly pressed, I doubt how reliable that test really is so I rely on my ears mostly.

From time to time, I ran into LPs that sounded fine on the out groove but the sound stage totally collapsed in the inner grooves. Most of the time I could conclude that these LPs were poorly pressed to begin with and no amount of anti-skate could have saved them.
Hi, Tom:

I have several old test and setup LP's which (collectively) have both blank areas for setting anti-skate (in the way you describe), as well as recorded signals which distort in one channel or the other (you adjust the anti-skate until the distortion is the same for both channels). If you want to try the recorded distortion method for setting anti-skate, several of the old Shure Type V-15 cartridge "torture test" LP's have this feature.

Having used both methods of setting anti-skate, I'm reasonably convinced that the method you used works as well as the others that I have tried. I now set anti-skate using the blank sections of a test LP. If you use this method, be sure that the blank sections are near the center of the LP, where the skating forces will be more balanced than at the beginning or end of the LP.

(As an aside, if you buy any of the 45-rpm versions of the LP's now being produced by Analogue Productions, one side of each LP is left blank. This gives you an entire side of ungrooved area with which to test the anti-skate. It's an excellent way to see if the anti-skate is properly adjusted for correct tracking from beginning to end of the LP.)