No, i use it only with the headphone in jack of my kpa. It works fine, i can tweak rigs on an loud level and when i go to my frfr i have only a little eq work after that. I have set headphone space up to 2.5 and headphone output to -7 dB
Cool! Good to know...
I'd be interested in your findings should you ever use it with other soundsources apart from the KPA... higher impedance cans usually have that "more of everything" quality to them but they mostly need decent amps driving them (and unfortunately, unless you get into nosebleed price bracket, most of them color the sound).