Update: received my PA2V2 from Gary after a 10-business-day wait, but it was worth it! Have briefly tested the amp with my DT 880 and IE8--it seems to work fine with the DT 880, and I suspect the IE8 is a bit too sensitive (@ 120 dB) to use comfortably with the PA2V2.
But: the PA2V2 was mainly intended for use with my HD 25-1 II, and the pairing is fantastic. Have immediately noticed improvements in clarity and the amount of bass, and an overall increase in warmth of the sound by using the PA2V2. Mind you, this is from an iPod Classic's headphone out only--I can only imagine how much better things will be using a Line-Out.