Dear T_bone, there is a formula to calculate the unknown effective mass of a given toneram, but it only works if you have the known effective mass of a reference tonearm and do know the resonance frequency of both tonearms with a given cartridge.

I do not have any other formula at hand.

With the Pioneer PL-90 and its tonearm you should get good results with cartridges having a compliance of 10 - 15 mm/N. Not lower. The Pioneer tonearm is not that heavy in effective moving mass.

Hope this is of any help.

Best regards.

I do not have any other formula at hand.

With the Pioneer PL-90 and its tonearm you should get good results with cartridges having a compliance of 10 - 15 mm/N. Not lower. The Pioneer tonearm is not that heavy in effective moving mass.

Hope this is of any help.

Best regards.