Steve, you are awesome :)....Great response, lol. I may have to call to chat about headphones soon. You also should think about a switch for using IEM's that need much less power to drive them and are subject, at times, to hiss. ;)....also please consider cross fade into the design. Headroom used to do that. I still have a couple of their older models with it and it works. Macintosh has a portable DAC/amp coming out this month that incorporates cross feed.