I'd like to throw in my two cents on amp stuff, from a different perspective.
I've been a STAX enthusiast for nearly three decades, and for at least two-thirds of the time, I've primarily been in the tube amp camp. So I can relate a lot to what others are posting (and I continue to have tons of respect for TOTL third party stuff).
However, with my current DAC set-up (Chord M-Scaler + Chord DAVE), my preference has shifted fundamentally toward appreciating more transparency. As a result, lately I've found myself satisfied the most when using DAVE as a DAC/Pre-amp combo and simply using 727 II as an energizer (bypassing/disabling its volume function altogether) for my 009/007. To me, somehow music seem to sound more intimate and natural with this set-up, even beating my Focal Utopia / Senn HD 800S straight out from DAVE most of the time, which I found quite amusing (given that directly driving HPs from DAVE has a clear advantage of having less electronic circuits in between).
Of course, I realize this is purely a matter of preferring certain iteration of sound characteristics over the other. Just wanted chime in as an example of other options out there.