If the X1 is like the XP10 the unit will need at least 24 hours of being plugged in to settle into the way it's supposed to sound. One draw back to the pass preamp you can't just unplug them and do direct comparisons to other preamps. If unplugged you are back to the beginning of that warm up period again.

Just curious if I am the only Pass owner who notices any change in sound once the power amp warms up a bit. Try playing an album and once it's over go back to the first track to see if you notice any difference. I hear the sound stage open up more and a bit more warmth.

The Pass has a lot of resolution and transparency, in addition to excellent micro/macro dynamics which puts it ahead of a lot of solid state but that euphoric feel of tubes isn't going to be there. It's hard to describe the difference but I am satisfied with the Pass presentation, it puts me some where between my CJ and Krell systems, I'd think of it as a sweet spot