Andy Schaub has posted a review of the Woo Audio WA22 ($1900) and WA6-SE ($1050) headphone amplifiers at Positive Feedback. His conclusions:
“Again, I got an almost electrostatic sense of drive of rhythm while at the same time remaining oh so laid back, very difficult to do with the HD800′s. Perhaps I didn’t get the visceral “thud” and “thwack” of my HiFiMan HE-5LE’s (also with Silver Dragon cabling); and there might have been a twinge of brightness to the top end, but I was running the amp cold with the stock tubes and all silver cabling on a notably bright pair of headphones, and still just couldn’t get enough of the music. Many people prefer the Blue Dragon cabling—or another brand—with the HD800′s. I’m kind of a detail freak (I used to own Spectral) and I want that clean, crisp dynamic range. So what can I say? The combination was phenomenal; and that was with nothing special save (a) my system itself and (b) the Harmonic Technology Magic Power Cord, which cost more than the amp itself at around $2K for a six-foot plus run. As I listened to Manu Katché and things settled in, I began to truly appreciate the pleasure of headphones again in a way I couldn’t even with my portable rig(s). Sure, they’re nice, and the Ray Samuels SR-71B does have a phase splitter in it; but it doesn’t sound like the Woo WA6-SE (nor the WA22 for that matter). As you can tell, I’m happy; and I think that’s all that really counts.”
You can read the full review here.