Anti Skating adjustment

Lewm might agree with himself, but he now needs to explain how a non-adjusted cartridge/tonearm can skate across the surface of an ungrooved record. If he doesn't believe this he can try it. He needs to acquaint himself with the physics of frictional forces and the intracacies of vector algebra to avoid making totally incorrect statements like this. Note that my observation does not necessarily promote the use of ungrooved records to set the optimum anti-skating force.

Regards, Maclogan: It's called centripetal force, a concept that's been around almost since that famous event when the apple clonked Mr. Newton on the head. The engagement of the stylus in the groove contributes to additional friction, sometimes simple phenomena (or simple minds like mine) don't need to be distracted by algebraic formulas for comprehension. Otherwise I agree, we'd all do well to get our facts right.

Personal approach is to listen for the "phantom center channel", or when the stylus is equally involved with both sides of the groove. My stylus, records and ears thank me for doing so, it's much less wearing on all of them.

Have fun & seasons greetings.

Peace,

Anti skate can be set by ear. Find a record with some vocals and some decent dynamics. Then set the force to zero. This works best with someone helping you, but you can do it yourself if you're patient.

Listen to the right channel and you should hear it almost lower in dynamic volume than the left (a bit recessed). Slowly turn the tracking force up, I mean very slowly a wee bit at a time. Eventually you should start to hear the right channel coming up and getting closer to what the left channel is producing dynamically. Then as you get higher you should hear both channels sounding more dynamic and just better and better. Move the anti-skate up very slowly now.

At last you will hear a fairly dramatic drop off in the quality of both channels. You have now gone a wee bit too far. Back it off a notch and you have optomized your anti-skate.

Enjoy,
Bob

Dear Maclogan, I really don't know what you are talking about. The fact that the cartridge seeks the spindle on a rotating ungrooved LP does not in any way disprove my statement that it is not a good idea to set anti-skate using an ungrooved LP. The skating force is due first and foremost to groove friction (acting in concert with the lack of tangency between the cantilever and the groove). If you don't have grooves, you don't have the skating force that we are interested in canceling. I did not say that there is NO force, just not skating force. On a smooth surface there is still some friction between the vinyl and the stylus tip, and the tip/cantilever are still not perfectly perpendicular to the radius of the LP (what I meant by "tangent"), so yes, there is a centripetal force present. But no groove walls. So, what's the problem? (In fact, skating force is also a centripetal force, just different in magnitude from what you get when there are no grooves, which is my whole point.)

I would not wish to misinform anyone, so if someone sees an error in what I wrote, I am more than happy to acknowledge that and glad to be corrected, if you can convince me.

The skating force that acts on a stylus to cause the arm to swing towards the spindle is generated by the friction between stylus and record. It acts along an axis which is tangent to the curve at the point where the stylus meets the record.

If there is no groove, then that simply means the amount and nature of the friction force is different depending on the stylus profile and how much, or how little, it digs into the blank record surface.

In other words the stylus will skate if there is VTF and the arm has overhang, unless something stops it.

The point to remember is that the stylus is stopped from skating by the inner groove, not constrained by the outer

When playing an LP, with enough VTF the stylus will stay in the groove, but there will still be unequal downforce on each channel. With antiskate applied, these forces can be equalised. That"s the way it is.

There is always a skating force. Depending on arm length and stylus, it will usually be from 10 to 30 % of VTF. The force varies across the record, so it might change from say 20 to 30 % of VTF from outer to inner groove in the case of a 9" arm.

If, with particular set ups, users prefer not to use antiskate, then they presumably feel the trade off is worth it. This doesn't mean there is no skating force.

The centripetal force In terms of the arm, which is the rotating part in this context, not the cartridge, would be that acting from stylus to arm pivot in reaction to its opposite component which is supplied by the friction on the stylus. The remaining component of that friction force acts to rotate the arm, and is the skating force we all know and love...