good call on finding out how the gain is configured. I think I will ask Schiit and see what they say!
I really love the LCD-2. It is amazing. As a newcomer to high quality headphones, I am blown away that I can get a similar level of listening enjoyment from my headphones as I can with my Wilson speakers driven with an Audio Research tube amp. Do they sound the same? Of course not. But when I am listening to them, I am nearly equally happy for the experience I am having at that moment.
I was using the Chord Mojo, but I sold it and went with the Jotunheim. I use it at my desk (with built in optional DAC Card) and listen to music while I work on my computer. I then move the Jotunheim to my audio rack and plug in some balanced inputs from my preamp to play music from the phonostage or dac that resides in my main system.
In short, I love the combo. The sound is excellent. Can the Jotunheim be bested by the competitors? Probably, but maybe not for the same price. $400 is a pretty great deal for that little amp. Also, I chose it partially based on the sweet spot of wattage power that Audeze recommends for these headphones. That said, I have only heard the LCD-2 through the Mojo and the Jotunheim. I do not have experience with other headphone amps.
Good Luck!