Question concerning the Mint Tractor

I did not compensate for the setup jig...actually, my arm was/is just a hairbreadth off of true horizontal with the back end down very, very, slightly. After setup with the Mint, I found that adjusting the VTA was unnecessary.

In case anybody wonders how I got the offset number:

• I modeled a hypothetical tonearm of 240mm in effective length.
• I marked a point where the stylus meets the record with the VTA being horizontal to the record plane.
• Another plane was added, which is 1mm higher than the original setup. This new plane represents a thicker record.
• I then measured the vertical projection of the stylus sitting on the plane that is 1mm higher.
• The overhand is now longer by 0.032485mm without VTA correction.

I don't know how relevant this number is in reference to distortion. This offset probably won't affect the sound much, but it will increase as the VTA increases or decreases from the original overhand setup using the arc protractor.

There is an excel file in this link at the bottom of the page. One can use it to verify distortion in reference to overhang.

http://www.enjoythemusic.com/freestuff.htm

I don't understand how changing VTA would alter/affect the Best Tractor's alignment.

Tvad, kindly bear with my somewhat leaden prose as I try to walk through it.

As an example, imagine changing SRA/VTA by moving the post of the tonearm up or down. Imagine the center of the arm's pivot fixed at the center of the post. (Some tonearms do not match this hypothetical.) Imagine the cartridge is correctly aligned to some known standard such as Baerwald.

Start with the stylus at a 90 degree angle to the horizontal plane of the record and the tonearm happens to be parallel to the record. Mentally put a stake in the exact spot where the stylus point sits.

Now, raise the arm on its post, which causes its pivot point to raise. The distance from the pivot to the stake has increased - the 'effective distance' (Pivot-to-Spindle + Overhang relative to stake) - has increased.

The length of the arm is fixed, so something has to give. The stylus point does not simply pivot at the point of the stake - it is moved/pulled rearward from the spot marked by the stake as the arm is raised. This changes its effective length relative to the presumably correct alignment marked by the stake, and thus changes alignment. Its not protractor specific.

The smaller the VTA change, the smaller the change to effective length, so whether a VTA change is worth a new alignment is up to your ears.

I think that's right.
 
Tim