By some manufactures and other industry professionals, medium mass tonearms are defined as having an effective mass between 9-25 grams. That would put VPI tonearms at the very low end of medium mass and that would account for their wide compatiblity with most modern MC cartridges.
Medium Mass or Low Mass Tonearms?
Many manufacturers of the tonearms used in audio today do not disclose effective mass of the arm. How can you determine what cartridge will work with the arm if you do not know the effective mass of the arm? Most VPI arms are low mass arms but many people still use medium to lower compliance moving coil cartridges on their arms. Even the 3d arm on the Prime is a low effective mass arm, lower in mass than the JMW 9. Wouldn't that increase the likelihood of excessive record wear? I would imagine you would want to use high compliance moving magnet cartridges on most if not all of their arms. What is the effective mass of Rega arms, Graham arms, SME arms? Also on my VPI table for example a benz glider falls into the good resonance area on the resonance calculator but it is a medium compliance cartridge better suited on medium mass arm Am I ruining my vinyl and not realizing it?