Were you using RCA interconnects before? If so could be the higher output signal with XLR is too high for the preamp. Just a semi-educated guess.
Spectral preamp/cables
I have a Spectral DMC20 Series 2 preamp and recently connected the cd player to the preamp with balanced cables to the Aux 3 input. With only one click of the volume it is much louder and at 2 clicks it is so loud you have problems hearing a person sitting next to you. Any thoughts about what might be going on. Thanks