OK, I finally hooked up my Zotl2. My entire rig was in storage as I completed a house renovation. Right out of the box, the Zotl2 sounds pretty darned good. It's a ballsy tube amp. My quick characteristic would be the balls of good ss with the palpability of tubes.
I'll be trying it with two different external psu's, an Uptone Audio JS-2 and a Core Audio Kallos. In the past, I've owned the Berning ZH270 and a 300B Berning Siegfried. The Siegfried was my favorite tube amp ever and I mistakenly sold it to a friend when I switched out of high efficiency speakers. It's the only piece of gear I've had that's actually appreciated in value.
As far as headphone amps go, my previous reference was an Eddie Current Balancing Act with KR PX4s (after cycling through just about every 300B out there since I was one of the first to purchase a BA and Craig's Mom lives near me and quite graciously gave me access to a bunch of different 300Bs), upgraded fuse, power cord and umbilical. I live in AZ and my audiophile friends here have cycled through most of the top tier amps.
I'll keep everyone posted. For those in doubt, the psu makes a very meaningful difference. Just hooked up the Core Audio Kallos and the a/b was immediate. My sources are an Auralic Vega, Chord Mojo and a vinyl set-up (Eddie Current custom phono stage, tweaked 1200 with Paul Hynes psu, Lyra Delos, Funk Firm platter, upgraded bearing and Origin Live arm).
Sonically, I prefer a dynamic, immediate presentation with a huge soundstage. Definitely more of a front-row guy. Just stating this up front so you can frame my assessment of things. I'm also an unrepentant tweaker.
The rig in my profile is dated. I'll have to update that.