2nd pivot for VPI 3D

It took 15 minutes to install, but about 3 hours of playing with it, essentially to satisfy myself that it was optimized.  I am amazed at the difference this simple modification makes.  I am not one to exaggerate, but here I go.  The bass is better, tighter, better defined.  The delineation of the musicians is greater, sharper focus, better illusion of front to back on live recordings.  I listen to a lot of acoustic jazz, prefer live recordings.  The dual pivot makes the acoustics where the recording was made more apparent.  It is like the difference between my Ortofon 2M Black and my Per Windfeld.  I am just stunned that such a simple thing can make this much difference and have no explanation for it.

That is a good point. My cartridge upon which these comments are made was an Ortofon 2M Mono SE, which is based on the 2M Black.  Lateral compliance is 22 micro meters/mN.  The arm is a metal VPI JMW 10, Series 3.  I have another kit on order for my 3D arm and will probably start with the 2M Black when it arrives because of the similarity of those 2 cartridges.  I am also eager to mount my favorite cartridge, a Per Windfeld, in the dual pivot modified 3D arm.  Later I might try either a Shure V15 or a Stanton 881 or both, who knows?  I have a lot of cartridges.

It is easy to back the second pivot screw out just enough to lift it off of the glide plate.  Doing so is identical to removing the kit.  This makes it very easy to compare the effect with and without the second pivot.  The instructions suggest starting with the minimum amount of pressure necessary to keep the point of the second pivot in contact with the glide plate throughout the entire arc of the arm.  Then increase pressure in small increments to compare the sound.  Increasing the pressure results in sound improvement up to a point, then it falls off.  With the 3D arm making this pressure adjustment is very easy to do by adjusting the azimuth weight out on the side with the second pivot.  A Counterintuitive is also an easy way to adjust the pressure of the set screw on the plate for arms that lack the adjustable azimuth weights.  You are doing nothing that can't be undone, practically instantly, and the mod will undoubtedly improve the sound of your Windfeld.  

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.