Personally, I'm begining to build a setup for home listening, but I happen to travel a lot. I'm aware that there is an entire segment of the market for portable/battery powered dac/amp units ranging from the $100 fiio's to the $300 oppo HA2. I'm curious what experiences those with Mid - High End HeadPhone rigs at home have had while going mobile. Do you adapt a unit like the HA2 - from 3.5 > 6.5 and rock a unit like that plugged into your phone? Do you say "eh" and just use a descent bluetooth pair of cans? I know that some great cans also work well off the regular audio jack on an iphone - so maybe this is also an option, choosing an interesting pair that is also friendly to non-dac/amp boosting? Thanks for shedding any light.