The effective mass of arm and standard HS-25 headshell is 13.4gm but the HS-30 headshell is 4.8gm heavier than the standard HS-25 headshell. Hence my question.
The effective mass of arm and standard HS-25 headshell is 13.4gm but the HS-30 headshell is 4.8gm heavier than the standard HS-25 headshell. Hence my question.
To a very good approximation it will be 13.4g + 4.8g, that is 18.2g.
It may look 'too easy', but it is good enough to use to estimate the low frequency arm/cartridge resonance. :)
The additional effective mass will be slightly less than the actual weight difference because we are talking about inertia rather than actual mass, but as Barry says the simple and easy estimation is good enough for resonance calculations.