I am more than happy to report back so that we're closer to the "truth" (in this case the truth being the parameters that should be used to offer the optimal cartridge alignment with the VPI JMW-9 tonearms):
My measurements of the mounting distance for the JMW-9T confirm the findings in the linked article from vinylengine, at least when it comes to the mounting distance, i.e., it is 222mm, and not 223mm as VPI stated on their website before removing this information altogether. If so, protractors from Mint for this particular tonearm are theoretically not correct since, as Yip indicated, they are machined with the assumption the mounting distance is 223mm and the effective length 240mm to conform to the Baerwald algorithm, which Yip uses for his protractors.
Based on the mounting distance of 222mm (which btw is the same as for the Rega RB-300, which VPI informed me had the same geometry as the JMW-9 tonearms), the effective length under the Baerwald algorithm is 239.5mm and not 240mm, which has been the target for Yip until now. So if my measurements are correct, JMW-9 tonearms set up with the Mint protractor might actually not be set up optimally. How big of a difference are we're talking about? I don't know, but I would very much like to find out.
My protractor will be shipped April 10, and ideally I would like to set up my cartridge using both protractors to compare the result and ultimately determine which one is more correct. If anyone has a Mint protractor made for their JMW-9 tonearm and is willing to participate in this experiment, please contact me.
My measurements of the mounting distance for the JMW-9T confirm the findings in the linked article from vinylengine, at least when it comes to the mounting distance, i.e., it is 222mm, and not 223mm as VPI stated on their website before removing this information altogether. If so, protractors from Mint for this particular tonearm are theoretically not correct since, as Yip indicated, they are machined with the assumption the mounting distance is 223mm and the effective length 240mm to conform to the Baerwald algorithm, which Yip uses for his protractors.
Based on the mounting distance of 222mm (which btw is the same as for the Rega RB-300, which VPI informed me had the same geometry as the JMW-9 tonearms), the effective length under the Baerwald algorithm is 239.5mm and not 240mm, which has been the target for Yip until now. So if my measurements are correct, JMW-9 tonearms set up with the Mint protractor might actually not be set up optimally. How big of a difference are we're talking about? I don't know, but I would very much like to find out.
My protractor will be shipped April 10, and ideally I would like to set up my cartridge using both protractors to compare the result and ultimately determine which one is more correct. If anyone has a Mint protractor made for their JMW-9 tonearm and is willing to participate in this experiment, please contact me.