i rate this thread "very entertaining" and "mildly contentious."
i'd give it a B+.
i'd rate the headphone out on my yamaha receiver a D+ or C-.
even my portable headphone amp is louder, cleaner, provides better separation, etc. etc. etc.
now... if i paid 2 or 3 grand for a home theatre receiver, you bet your sweet arse it had better have a pretty decent headphone out.
but, i paid nothing near that. so it's not surprising it won't power my k702s.
On a personal note, I've owned any number of qood stereo amps and quite a few dedicated amps up to the LD MkV. Using my HD650, I can detect no significant difference between any of them. I can detect differences between amps, not because they're dedicated or integrated but more because they suit the 650 better or worse; or maybe they're just better designed, period. I say don't worry about whether the amp is dedicated or integrated; just find the best sounding one you can. If a speaker amp sounds great through speakers, chances are it will sound great through your headphones as well.