Mijostyn, There you go again! Velocity is NOT a factor in determining the friction force. Friction force is very simply equal to the net force vertical to the contact surfaces of two objects (VTF in this case) times the coefficient of friction, which is different for any two materials in contact. So pre-supposing an effect of velocity on the skating force is invalid, if the angle in the equation for skating force is equal to the headshell offset angle. If velocity was a factor, you would have to change AS significantly for 45 vs 33 rpm LPs. Not to mention that the outer groove velocity is so much greater than the inner groove velocity that "velocity" would dominate the problem of setting AS. In your last post, you say the angle IS the headshell offset angle, but then you go on to say, "The reference is to the arm’s pivot not the record". I am not sure what that means. Headshell offset angle is the angle by which the headshell is "bent" with respect to the arm tube, as I am sure you know. It’s a constant at all times. But tracking angle error (TAE) is constantly changing during the course of play. This aspect of TAE causes a constant shift in the direction of the friction force vector which alters the magnitude of the skating force. So I posited that the "angle" in your equation could be defined as TAE + headshell offset angle. At the null points, TAE is zero but headhell offset alone still causes some skating force.
A new way of adjusting anti skate!
The appropriate figure is 9 to 11 percent of VTF. So if you are tracking at 2 grams you want 0.2 grams of anti skate.
My Charisma tracks at 2.4 grams so I should set the anti skate for 0.24 grams..................................Bright light!.
I readjusted the Syrinx PU3 to zero so that it was floating horizontally. I set up a digital VTF gauge on it's side at the edge of the platter so that the finger lift would be in the cross hairs, activated the anti skate and was easily able to adjust it to 0.24 grams. I started at 0.18 grams and just added a little more. Whatever you measure the anti skate from it has to be at the same radius as the stylus. If you do not have a finger lift at the right location you can tack a toothpick to the head shell and measure from that. As long as you have the whole affair balanced at zero you will be fine. Added cost $0.00 as long as you have a digital VTF gauge.
I would not buy stock in Wallyskater.
- ...
- 98 posts total
In the above, I confusingly wrote, "So pre-supposing an effect of velocity on the skating force is invalid, if the angle in the equation for skating force is equal to the headshell offset angle." That’s wrong on the surface. I meant to emphasize that velocity is not a factor, regardless of angle. And as a separate matter, the equation quoted by Mijo is also invalid if it is dependent only upon headshell offset and not TAE. |
@normb , listening for distortion and watching the cantilever displace as it hits the record are sort of arbitrary. To get a good cartridge to distort requires very high groove velocities that over estimate the AS force required. The cantilever displacement was useful in the days of high compliance cartridges but not with the ones we use today. They are too stiff. Frank Schroders advice to set it so the arm slowly drifts inwards when placed between grooves in the run out section is probably the best low tech way of setting it. The equation I mention above is very specific except there is no one value for the kinetic coefficient of friction. There is a range. Using the Wally Skater and my device are really very simple and you know exactly what you are doing with a very specific target which is reassuring. Then you just forgetaboutit. I have also used my modified gauge to verify that the Schroder method does indeed come close and using the blank record method consistently over estimates the AS force. I did not study cantilever displacement because by the time the cantilever starts deflecting with my cartridge the AS is way off. |
TL;DR after @millercarbon’s and @lewm’s first posts (both of them being excellent, and I agree with them). Trigonometry aside, and one thing that is lost on most individuals is "what are you adjusting for?" The obvious answer is distortion, but all too frequently (and very much like tracking force), being able to track the most challenging A-S track on your test record is not necessarily ideal. Excess tracking force and anti-skate (even if within your cartridge manufacturer’s specs, as far as tracking force is concerned), will likely compromise the dynamic presentation. That’s a big "no-no" in my book, and the more I do this stuff, the more my final tuning steps address dynamics. Now, in no way does this mean that I like distortion (quite the contrary), but given the choice of very good distortion performance with outstanding dynamics, vs. outstanding distortion performance and mediocre dynamics, I’ll always choose the former. You might say that in phrasing the above choice the way I did is a straw-man argument, but the fact is that dynamics fall off a cliff very quickly with either too much tracking force or too heavy a hand with anti-skate. I make a big deal about this in the free setup report you can pull down from my website. ... Thom @ Galibier Design |
- 98 posts total