Hum suppression

I am finding the hum levels coming from my Supercap and CDSPS, and to a lesser extent from the 135's, increasingly irritating. This is especially so when the system is not in use.

The system resides in our living room which means it is not dedicated for myself or music listening.

If someone has any suggestions for getting rid of the hum it would be highly appreciated.

I already have a dedicated spur.

Would some sort of cloth cover to drape over the power supply help? Which material is best at suppressing 50 HZ hum?

Best regards