I've tried driving my Cornwall IV with a McIntosh MC275 VI, Rogue Stereo 100 with Dark upgrades, BoyuuRange A50 mkIII 300B amp, my Audio By Van Alstine 600R hybrid amp, and my Enleum 23R. I own the last 2 and the Stereo 100 and the 300B amps were my friend's amps. The MC275 VI was borrowed from a local dealer. My 600R beat all the amps except one, the Enleum 23R. The 23R was a class above all the others in terms of transparency, image clarity, soundstage width and depth, and musical engagement. This amp has an organic sound unmatched by any other amp that I've tried.
I won't go into details about its design because you can get that online and in several reviews. John Darko recently posted a YouTube video rave review on the 23R. Other reviews include 6 Moons in which Srajan said the 23R is the best solid state low powered amp he's ever tried. As a bonus, it's a state of the art headphone amp as well. It's not inexpensive and there's a wait list to get it but it's worth it imo.