While checking for ground loops or other grounding problems is worthwhile, Grados often hum if operated within the range of the motor field.
Changing to a cartridge other than a Grado is one option but you can also look for shielding material to apply to the bottom or your platter or around your motor. Someplace there is a magazine article on modifying a Thorens or AR table to allow use of a Grado but I don't recall where.
Changing to a cartridge other than a Grado is one option but you can also look for shielding material to apply to the bottom or your platter or around your motor. Someplace there is a magazine article on modifying a Thorens or AR table to allow use of a Grado but I don't recall where.