As promised, here are some pictures to give you all an idea of the size of this behemoth. The unit on the right is an AU-717 (same size as the 719, 819 & 919).
I've been lusting for and looking for an AU-919 for a few years, I came across a few but they did not meet my standards. I even prepared in advance by purchasing a mint condition 919 face-plate in the event I located a clean/working 919 (with original outputs), this way I could jump on it even if the face-plate was less than perfect.
As hard as it has been to find the right 919, I never thought I'd ever see an X1. So when I came across this hen's tooth I did not hesitate to act especially because of the pristine original condition it's in. I figured, if it's unmolested and still working, that's a good sign.
Yes, I know there are plenty of risks, black flag nightmares and such but hey- you don't live if you don't take risks right? I haven't really put this bad boy through a real workout to see what it can do. I'll wait until it is brought up to snuff by a qualified tech before I do that.
So far, it has everything you would expect and then some. Power, dynamics, clarity, effortlessness all while building on the clear neutral sound of the x19 line (I have a 719).
There's no doubt, the AU-X1 really is a special amp.