Audio360's round table discussion of the WA7tp tube power supply companion to the WA7 headphone amplifier is encouraging to say the least. Specifically, it is worth highlighting Kevin Venable's impressions:

“Ah cool... I find lapsteel to be a hard instrument to listen too on a lot of gear. It sounds too harsh, a bottleneck slide playing like in blues as well. It is quite enjoyable with the WA7tp. My prefered rig for this kind of music has always been my vinyl rig, but this is getting closer.”

The entire discussion can be read here: early impressions: woo audio's wa7tp