It is easier to visualize what is happening when you have the kit in your hands and no matter how articulate our words are, they fall short. I will try. Visualize a tripod, that is a platform with three feet. The first foot is the unipivot of the VPI arm which you are familiar with. The second foot is the second pivot, think of it as an outrigger like might exist on a canoe, which supports the tonearm and prevents it from tipping on the unipivot. The third pivot is the stylus resting in the groove of the record. We have just defined a plane in space. The azimuth is very precisely defined by the outrigger or second pivot. So adding pressure or weight to the second pivot will not change the azimuth as it did before, because the second pivot will prevent movement. The three points of contact fix the arm in the plane defined by those three points. So with the kit installed, the side to side rotation about the axis of the unipivot is eliminated. The arm is stable like a gimbal bearing tonearm. The trick is to optimize the amount of pressure exerted on the second piovt as azimuth is fixed and stable. When you see it the simplicity will become apparent. What is amazing is how such a simple idea can have such an extraordinary effect.
