I have Sonar X2 Producer, and when I plug my mic (AKG 120) into Edirol UA25 (for phantom power) it sounds great, but as soon as I turn on INPUT ECHO to monitor it!! Distortion and Fuzz...like its overloaded or something.  The mic and the interface all work fine ( I have tried other mixers too)..I can record a nice clean signal but seems to be a problem when INPUT MONITORING in ON?? , which means its hard to monitor?
Any help advice would be appreciated 

If you monitor at the interface instead of the software, you shouldn't get distortion. Are you monitoring with the speakers on?
Also, this isn't the X series forum; it's for older versions of Cakewalk software.