Got these on a sale, and was very pleasantly surprised.  Originally, I was looking for something that isolates well and does not sound tiring for use in the office, but ended up using them as my first choice HP (instead of Alessandro MS1, Porta Pro, KSC55).    I have been using them with uDac2, 2nd gen iPod nano, and Audigy 2 ZS.  They are easily driven by any of these sources.  Also, their low impedance does not seem to be a problem. They sound engaging with almost anything without being tiresome or offensive, be it highly compressed mp3s of...