I own a pair of Audion Black Shadow 845 monoblocks. They are outstanding, especially with the 845M tube. Self-bias circuit, no problems, very robust. The Black Shadow has been replaced by the Elite, a 3-box monoblock + power module upgrade based on the Black Shadow design. These amps use silver wire in the audio path too. Black Shadows are scarce in the US. The Elite can be ordered new. I've heard the deHavilland, ASL and Bel Canto and Art Audio 845s. I prefer my Audions but I think if I didn't have them, I'd own the Art Audio Carissa though there's nothing wrong with the others.
Phil
Phil