I think it's likely that my source is too quiet, although I have no clue how to fix it. Last night I was using a Yamaha CD player that has an adjustable output, and I had it set to the lowest, hence the Asgard picking up the slack and being almost to the max. I experimented with different settings on each and found the Asgard was the best even on full. Don't worry, I wasn't frying my ears. With my DAC hooked up to my computer it's much lower, but my DAC doesn't have adjustable line outs.
Do class As sound better than ABs? The Asgard generates much more heat, so is that heat serving a purpose or is it just "for show"?
It's good to hear that the Asgard works well with high quality IEMs. As before, I am amazed how well it works with my DT 990s but it actually sounds a little worse than the built in output with my HD 558s and Custom One Pros, but that isn't a concern since those don't really need an amplifier.