I’ve been using Wilson Watt Puppy 7 with Pass XA25/XP22 as well as the First Watt SIT3 and Pass X350.8. Digital via Denefrips Terminator Plus (streaming thru a Bluesound Node 2i; analog via a Linn LP12 Klimax (Exstatik cart.) and assortment of Audioquest & Linn interconnects/power cords, and Transparent Ultra speaker cables. Room is 22’ x 22’ with a A-frame ceiling (centered on axis) that peaks at 24’.
In a nutshell, the Wilson/Pass combo is superb and the speaker’s efficiency allows excellent performance from the 18-wpc SIT3, which is by quite a margin the most satisfying of the three amplifiers. Only limited by moderate volume levels via digital input (the LP12 has considerable more gain), 18 watts goes a long way and the warmth, detail, and transparency are top notch. At the other end, the 350.8’s only benefit is at elevated volume levels with rock/pop or anything where LOUD is an essential element of the experience. By comparison, it’s essentially unlistenable with jazz/vocals/insteumental music at moderate or lower volumes next to the SIT. The XA25 is the happy compromise, with adequate power for all but the most demanding all-out rock outs, while still very satisfying across all genres.
Despite being over 15 years old, the WP7 remains and extraordinary and competitive speaker for its size and an outstanding match with Pass/First Watt.