Thanks Marshall. I used to translate user manuals into French and we always tried to make them better than the originals. Sometimes we actually succeed.

With a sensitivity like that it's not going to be easy to stay clean. These pro crossovers are really meant for power amps with a volume control up front. Even if you were to modify the DCX to bring the outputs down to the same level as the DAC chip output (about 1.7V RMS) you'd want to attenuate before the amp. I certainly need to in my rig.

On the older integrated amps I've owned, the volume seems to be the last thing in line. So for example coming in the tape monitor is subject to volume control. You think yours are not like that?
Of course you could build attenuation into your cables.

EDIT: Come to think of it, 1V out of the preamp seems low. A CD player is usually 2V out. Do you have a way to measure this?