Tonearms with no anti-skate adjustment

Moonglum, In your model using a balance scale, the restorative force is gravity, acting to restore equilibrium once you remove the upgoing force you applied in order to raise the pan on one side.  At the starting point, where the two pans are level with each other in the same plane, gravity exerts an equal force on both pans, because they are equal in weight or mass.  So equilibrium is reached when the pans are level with each other.  Your upgoing force is tantamount to reducing the mass on the side that it is applied.  It is a momentary force opposing gravity. A tonearm is not entirely analogous to a balance scale, because it is supported at TWO points, at the pivot and at the stylus.  The stylus exerts an upward force on the tonearm equal to VTF. When you mess around with the vertical position of the pivot point and change nothing else, there has to be a shift in the fraction of the mass that is supported by the stylus (=VTF), vs that which is counterbalanced by the counter-weight, which can only exert a fixed downward force equal to the effect of gravity upon it.  The change in VTF is usually small, I admit, for the usual very small changes in VTA that one is trying to achieve.

The balance scale model is flawed as a model for a tonearm.

Lew,
While I do not deny what you’ve said, remove the other supporting point, zero VTF so that it is balanced and floating freely, then the tonearm becomes analogous to the scale i.e. a stable balanced tonearm will behave in the same way.

Your beliefs are contrary to those who have measured the force at the elevated stylus point and compared with “horizontal” arm measurements for VTF.

Have you performed such measurement to confirm your belief?

moonglum

Your beliefs are contrary to those who have measured the force at the elevated stylus point and compared with “horizontal” arm measurements for VTF.

Have you performed such measurement to confirm your belief?

It isn’t clear what you’re asking here.

I can tell you that - all other things being equal - if you increase the height of a statically balanced pickup arm, you will also increase VTF, however slightly. Similarly, if you decrease the height of a statically balanced pickup arm, you will decrease VTF, however slightly. You can easily measure this with a proper VTF gauge.

I’m really surprised that there is any debate about this. It’s pretty basic geometry and physics, and easily measured.

And yes, I’ve measured it.

When you change the vertical position of a pivot, you are in effect changing the horizontal distance between the stylus/record and pivot point of a fixed length tonearm, which in turn changes the balance. As we reduce the distance between stylus/record and pivot, the measured force at the stylus tip will be reduced.  Any adjustment to the vertical position of the pivot that results in the pivot interface and the stylus/record not being inline will result in a lowered measured force.

This can be easily demonstrated. Hold a 5lb weight 45 degrees away from your body (the weight will be farthest from you body). Do the same at 23 and 67 degrees. Tell me which one feels heavier when the only thing that has change is the distance between you (pivot) and the weight.