There's a battery in it but it's running off the PSU now. Just the way I like it.
Initial Quickstep impressions after 3 hours of random music:
Soundstage: A+ - This is great. So wide and 3-dimensional, yet everything seems to be in its right place.
Flavor: Neutral! Not bright, not dark. It just strips the veil of whatever music you're playing and serves it to you on a silver platter. Nothing added, nothing removed. Bass is dry, hard-hitting and textured. "Clarity" would be the one word I would use to describe this amp.
Power: IEM perfection. On low gain my preferred listening level is reached at exactly 50% volume.
Build: I'm pretty confident I could run this amp over with my car and it would still be playing. Built like a tank, but not overly heavy.
Cons: Heir Rendition 10 gives you a fatter bass for heavy-hitting electro. Also the Quickstep is slightly oddly shaped if that matters to you. Oh and no charging circuit. I like the ordnung muss sein/reinheit über alles approach but a charging circuit would have been nice.
Works well for rubberbanding with the DX50