I doubt the lack of power is the issue using the CDM. I use the ak120ii line out (or max volume) which outputs 2.3V and feed that to the CDM. Listening to the HD800 i have the volume pot around 3 o'clock for the average recording and the HD800 is not the easiest headphone to drive. I don't have the LCD-XC but judging from the specs and user comments it is an easy headphone to drive. I estimate i would never need to go past noon on the CDM volume pot if i had the LCD-XC. I think your disapointment regarding a lack of bass is inherent to tubey sound. Just my opinion of course.