I can't speak to a 'house' sound except that I've owned both the X 2.5 and X-1 in the last few years and both seemed quite neutral and should not interfere with the 'house' sound of your other components.
I should note that I've never listened to either preamp without being connected to my Foundation Research LC-1 passive and dedicated line conditioners.
BTW, with proper line conditioners installed, the X 2.5 and X-1 sonics seemed identical. In other words, any potential sonic benefits provided by the X-1's seperate power supply seemed to be negated. That being the case, I'd definitely opt for the less cluttered (one less box) and less expensive and otherwise apparently identical X 2.5.
-IMO
