It's been my experience that if you change something out and all of a sudden get 60 Hz hum, there is a ground fault somewhere. Before spending any money, start with the isolation drill. Disconnect the cartridge leads and move the arm across the platter at zero attenuation. Repeat with the headshell removed. Make sure to double-check the preamp / power amp combo by going to zero attenuation on a non-active input selection after the turntable leads have been disconnected. A final check (if feasible for you) is to test a totally different table.
Good luck and happy listening!