You can eliminate the noise after the fact with NR, but you may lose some of the musical content with it. A much better strategy is to find the source of the noise and attack it there. CEP by itself doesn't produce hum: it's in your equipment, or the way it's configured, or the sound card. There is a lot of information about getting rid of hum, from dressing your cables properly to using the right sort of interconnects, and I won't list them all here, but the type of noise may very well tell you where it is coming from. Good luck tracking it down.