A few initial notes and questions:
-On a power basis, seems pretty versatile. Running balanced on 2x voltage, more than enough power for the HD800. (I'm not sure yet whether I'd say it's an especially good combination, but the power is there.)
-However, not quite enough power to drive Fostex RP driver based headphones (Argon, in my case) well, at least in single-ended. I'd love to try this balanced, but my Argons aren't wired for that.
-Happily drives the MD+, of course
-On max output, according to the app, it's providing almost 2vrms, potentially pretty good for feeding an amp. I tried this setup for a while with my RSA SR-71A, and seemed to work quite well.
-But, testing that setup did indicate to me that the amp section of the ES100 is probably holding it back a bit. (Would be great to see them come out with a larger version that has a beefier amp section and improved controls, and a volume display of some kind on the device would be sweet
-EQ works well (good for iSine users!), although the requirement to hold the preset name for four seconds or w/e in order to save the setting confused me at first.
Questions:
-If you set EQ through the app, then plug the ES100 into a computer using a cable, does the EQ stay active?
-Adjusting the volume with the buttons is surprisingly difficult. Single tap makes minute, inaudible adjustemnents, while holding the button down tends to make large, hard-to-control changes. Is this something folks get used to, or do they just give up and control the volume from the app? : )