But does the 8x impedance guideline "technically" result in increased detail, or was NwAvGuy's blogger post more about how Sennheisers don't have flat impedance response, and if you use an amp with a high output impedance (and quite possibly many other design factors not taken into account) the result is more bass on top of the HD650's already higher neutral bass and subsequently some looser bass that bleeds over the mids (like many headphones with that much bass in their frequency curves already)? Do "most" headphones have noticeably nonlinear impedance response curves like NwAvGuy claims, or are we making assumptions because one guy who was banned said something that sounded plausible even though in many ways that banned guy misses/omits the bigger picture?
This isn't meant to discredit you, PurpleAngel (you know I like you), that whole paragraph above is meant to make you think "is there holes in either theory?" before passing along advice. You yourself said your 40-ohm Audio Technica's sounded decent, I'm just saying maybe there's more to the quality of an amp than output impedance, current, and voltage.
Conjecture and assumptions lead to beliefs like the earth is flat, and at the center of the universe, and that an amp is suited for the portable role even if it's too big for most pockets and all the connections and controls should be clustered on the front face.
