Pivot to Spindle distance

Elliot, In the end, it's effective length that counts, along with headshell offset angle.  Since effective length is the sum of P2S + overhang, since different designs feature different headshell offset angles, and since there are at least 3 different commonly used geometries that all result in two null points on the surface of the LP (and actually a myriad of such solutions that just haven't been associated with the names Stevenson, Baerwald, or Lofgren), there are many "solutions" to the problem.  Depends where you want to place the two null points (closer to the spindle or closer to the outermost grooves, for example) and how much tracking angle error you are willing to tolerate when the stylus is NOT on a null point.  And I am as bored as anyone else with this topic.

lewm

thanks,

It does make me respect the people who engineer our great stuff!

Elliott, It is only a matter of rather simple geometry. Lewm has said everything else that needs to be said.

Lofgren and Baerwald published their papers on tonearm alignment in around 1940, when the only records were made of something other than vinyl and all were mono 78s. And most people still owned wind-up Victrolas with megaphone speakers.

Mark,
IMO, when the manufacture designed a tonearm, they calculated and set the P2S distance and all the geometry of the tonearm to get the best out of the cartridge with the least of distortion possible. When you changed the P2S distance, it will lead to the change of the offset angle of the cartridge mounted on the tonearm. It works, but it might cause more distortion (the ear might not detect it) and affect the life of the tonearm (might cause more friction on the pivot bearing).
In conclusion: If it was mine, I would spend sometime to reset as the manufacturer recommended.
Enjoy,
Calvin