You'd be safer with installation of an isolated ground since your existing ground is apparently noisy. If your strip/conditioner is a Chang, or similar with integral surge protection, then a ground is required in order for the protection device to have a place to shunt any supressed transients.
You could also go over your electrical system's connections for tightness & cleanliness, including the ground stake connection. Fixing any issues there could eliminate the hum problem while retaining the safety of a proper ground.
You could also go over your electrical system's connections for tightness & cleanliness, including the ground stake connection. Fixing any issues there could eliminate the hum problem while retaining the safety of a proper ground.