Tonearms with no anti-skate adjustment

Moonglum, Just to clear up a basic point in our discussion, I think/thought that originally you were claiming that LOWERING the pivot point would.... etc.  But in your last post, you are talking about RAISING the pivot point.  In the latter case, the set VTF will go up, because your shoving more of the total mass onto the cantilever/stylus which must support it.  So, to summarize my position, move pivot point down in the vertical direction and the set VTF goes down.  Move pivot point up in the vertical, and the set VTF goes up.  And this is for a static balanced tonearm.  For a dynamically balanced tonearm, one with springs, etc, to set VTF, the effect is largely obviated.

A very simple analogy is to think of two guys carrying a sofa up a staircase.  Which guy is bearing most of the weight?  The guy on the bottom.

Testpilot, You wrote, "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."  I don't know what the phrase "pivot inteface and the stylus/record not being in line" means, but I do believe that moving the pivot down vs up does not have the same effect on VTF.  Maybe if I better understood your lingo, I would agree.

Buy a blank vinyl record, and adjust accordingly.  Takes 30 seconds.  You will hear a difference if you have a decent tonearm.

@oldtech04  -  That method has been proven invalid since groove modulation plays such a large part in anti-skate.  Even if anti-skate is perfect on one record, it is unlikely that it will be correct on every other record.  The reason is related to the impact of groove modulation to anti-skate orce.

Effects of tonearm geometry and mass distribution on the measurement of VTF :

http://www.tnt-audio.com/sorgenti/in_balance_e.html

There you go. Settled once and for all :)

Not a big deal with many tone arms. But a very big deal with arms unipivots with under slung counterweights. 

@lewm

So, to summarize my position, move pivot point down in the vertical direction and the set VTF goes down. Move pivot point up in the vertical, and the set VTF goes up.

Not so - it depends where you start. If the arm is level, then moving the pivot point up or down moves the counterweight closer to the pivot and increases vtf in BOTH instances. In your example you would have to start with the arm up at the back for your statement to be true.

@hdm

Effects of tonearm geometry and mass distribution on the measurement of VTF :

http://www.tnt-audio.com/sorgenti/in_balance_e.html

There you go. Settled once and for all :)

If you calculate the change in overhang from moving the arm up or down 5mm then there is more distortion caused by this than the increased tracking force.

Not a big deal with many tone arms. But a very big deal with arms unipivots with under slung counterweights.

Only if you play lots of warped records.

The reason the counterweight is often placed lower on the unipivot is to stabilise the unipivot bearing by lowering the centre of gravity below the bearing point. This lowering of the centre of gravity also has a mechanical benefit of damping stylus motion.

Lowering of the centre of gravity has little, if any, benefit on a conventional arm with captured bearings. In fact if you read up on Pierre Lurnes design of the Romeo unipivot he presents an argument for having the centre of gravity slightly forward and only slightly below the pivot point to reduce the pendulum effect of a lowered counterweight which is not desirable on warped records.

At the end of the day the designer has to balance the pros and cons of each design facet and choice.