I have WP7's and tried a bunch of tube and solid-state amps. I didn't like the match of low-powered tube amps with the WP7's as much as I did with my Sophias, but as other posters have said, tubes give a fuller midrange and a bigger soundstage with better dimensionality of instruments and voices. I even tried a pair of Cary 15wpc SET amps and they just didn't have enough power to drive the WP's to satisfying levels. I remember listening to a UK pressing of ELP's Lucky Man and seeing the 300B power tubes flashing like disco lights to the music--I was driving the amps that hard. I thought the WP7's sounded best with big push-pull tube amps like an Audio Research VT100 Mark III and Conrad-Johnson Premier 140 I had, but again, the drawback was losing the last degree of bass and dynamics the Wilsons are capable of. So I tried SS amps like the BAT VK-500 and VK-600, and unlike the poster above, couldn't get used to the lack of soundstage size. Bass and dynamics were great but the music was just too laid-back and reticent in the mids for me. Now I have some Essence SS amps that have the best bass and dynamics I have yet found but with at least some of the dimensionality of tubes. Also great transparency and detail. Yesterday I was listening to Michael Jackson's Thriller--yeah, I know, but the strange little dude was pretty good back then, and there were some bass transients that absolutely startled me. Like the other poster said, WP's are extremely revealing of upstream electronics, so a lot of experimentation is necessary to get their best.
