Anti-skating question

Thanks Jayboard, those were very helpful

You are right to set anti-skating by using modulated groves rather than blank bands on a record. The inwards force arises because a tangent to the record grooves, at the point of contact of the stylus, makes an angle of about 20 degrees to the line from the stylus to the pivot. The friction between the record surface and the stylus exerts a force on the stylus in a direction which is tangential to the record, and this is opposed by the tone-arm which pulls in a direction from stylus tip to pivot; however since these two forces are not acting in opposite directions, there is a net inwards force which is given by the following equation. Inwards Force = F * sin(theta). The angle theta, between the line from the arm pivot to the stylus and a tangent to the record groove is easy to calculate, the friction is a different matter One might expect that the friction would be less when the stylus rests on a blank band, but your observations contradict that; I also noticed the same effect with my turntable; and there was a long experiment conducted by Helge Gunderson on the Vinyl Asylum about the same question. My guess is that the stylus is carefully polished so as to reduce the friction between it and a V shaped groove, and when the stylus rests on a blank band the friction is higher, as it is the tip of the stylus which determines the friction in that case. The key point here is that many people (including the article by Laura Dearborn) recommend setting anti-skating using the wrong method, ie so that the tone-arm moves slowly outwards when resting on a blank band. Experiment shows that when anti-skating is correct it usually moves inward. Brian

Interesting. My results were counter-intuitive (or at least counter to my expectations), and it's reassuring to know that others have gotten the same kind of results. Thanks for posting.

This question is for Jayboard: Can you tell me the results of the O.L upgrade. What did they do, I know they replace the tonearm internal wiring. Is this one run all the way to the rca's, did they replace the end of the arm with a weighted stainless end and the same upgraded counter weight? What was the cost? respond to fcone@mediaone.net thanks JP

Hi, Joepetro. Not to put you off, but I don't think you can do better regarding what's involved with the upgrades than the OL site, www.originlive.com. Anyway, the numero uno upgrade is structural, not electrical. OL re-machines and replaces the counterweight and counterweight stub to reduce resonance in the arm. Upgrade of next importance is internal arm rewiring. After that the rest of the wiring. I bought direct from OL new RB250 arm for ~$130 with first and second upgrades at ~$88 and ~$82, respectively. You can probably do better buying in U.S. from Galen Carol Audio, and I think there's another American distributor now. BTW, OL has a pretty good selection of phono cartridges, and if the exchange rate is still good, buying overseas from them amounts to a very good deal. HTH.