Hi there! I wondered the same thing about the power conditioner before building the cabinet (wanted to keep the unit as small as possible), but decided that since the amp will be used in many different locations with varying power sources, it's likely wise to have a conditioner. There's plenty of room for cabling power cords both behind the amp/preamp/PC, and in the lower speaker cavity. I get no hum or hiss so far! With the current cut out configuration of the back panel I can easily insert a xlr into channel 1 of the carvin amp, but would need to make the cut out larger to accommodate the channel 2 xlr input (because the back panel is not far enough away from back of the amp unit, though a 90 degree 1/4" mono fits into channel 2 just fine). I think a redesign of the cut out for the back panel should take care of the spacing concerns for accessing the back of the amp/preamp/PC.