The question was "What low cost solid state option for Zu." Luxman 550A II at 20 watts class A is more than enough for any Zu speaker. Luxman sounds "fantastic" with Harbeth 40.1, spent several hours with this set-up. Spent weeks with it driving my Kharma 3.1 ce's. One can be had here used for a good price. Luxman will sound great even with stats. Read the review. I also heard it with Maggies. I'm not a stat guy, but it was a beautiful mid-range experiance. Peace and Good Listening, Pat.