I used on to damp the 'ringing' of the platter of a Pioneer TT. That wordked fine. Never used them to diminish hum though.
Keep in mind that you'll have to adjust the VTA (Vertical Tracking Angle) of your cartridge if the replacement mat is thicker or thinner then the original mat.
Keep in mind that you'll have to adjust the VTA (Vertical Tracking Angle) of your cartridge if the replacement mat is thicker or thinner then the original mat.