Or you just buy the Topping A90. Should be plenty powerful for nearly everythingIn theory the PA5 as about the same power delivery as this Burson, but it was not designed for headphones. Off the bat it won't work with regular unbalanced headphone cables, you will need two negative leads.
DC offset considerations have to be checked too. All agreed that more power can be delivered with less noise and distortion, but why compare Apples and Oranges?