Hum de Dum

My System has a very low hum running thru it. It seems to go away if I employ
a ground removing plug. Is there a better way to get rid of the hum. I mostly listen to 
CDs played directly from my amp. No preamp. What else??
Lots of threads on here and elsewhere on the net that can provide some step-wise guides on removing ground loops that appear to be causing your hum (based on the ground lift being effective).  It's all about isolating which component is causing the issue.