This is a bit of an odd request.
First some background, I've been reasonably happy with my Calyx DAC going direct via RCA to my LA7000s. I finally got around to getting them balanced - the balanced output on the Calyx sounds much nicer. But, much to my surprise and chagrin, it is much quieter, too quiet, I need an amp.
Thing is, at a hi-fi show recently, I found that even a damned good pre-amp (the Classé CP-800) was noticeably reducing sound quality in our setup, so we used digital volume control via the DAC and BitPerfect. I want to do this with my headphone setup, so I'm looking for the equivalent of a balanced power amp that won't vaporize my ear drums and/or the LA7000s.