100W+ solid-state amps known for beautiful mids

@peguinpower. I had the exact opposite experience with the Pass X150.8 and Audio Research.  I found the ARC to have wonderful mids and the Pass very sterile lacking any midrange magic.  Could be system dependent but it's crazy how we have totally different experiences.  

Having owned and auditioned lots of amazing SS amps over the last 50 years, while some are very good. If you want great midrange just get a tube amp. I stayed away for decades until finally Audio Researched produced the auto biasing and microprocessor controlled tube amp that had good tube life… Reference 160S. My question to myself has been, why didn’t I do this decades ago! My system is now all tubes, and it is more involving and satisfying than I ever imagined possible.

@gryphongryph I am using VTA SP14 which is the predecessor that Don Sach's is based on. My speakers are ATC SCM19. The founder of ATC, Billy Woodman recommends 100W+ with high damping factor on his speakers, so I'd like to adhere to his recommendations. For the reason, I think it's headroom, since transients require a lot of current.

@ghdprentice I believe that my speakers are incompatible with the vast majority of tube amps. I'm taking advice on amplifiers based on the ATC founder Billy Woodman, in that ATC speakers are best with 100w+ class a or ab solid state amplifiers with high damping factor. I think the problem is that most tube amps have extremely low damping factor, which apparently doesn't mate well with ATC speakers, though I have yet to try myself. So for now, I'd like to stick with a solid state power amp with a tube pre-amplifier to get at least some of the tube magic in! If that doesn't pan out, maybe I'll try one of those monster 100W+ tube amplifiers like the Rogue 100, and if that doesn't work, then I might move on from ATC and try something more tube friendly like ProAc bookshelves.

New Classe Delta, 12W in class A for stereo amp (30W for monoblocks I believe) sweetness, more dynamic, details and bass solidity than the tube-based ARC Reference setup it replaces without sacrificing on mid-range. There's a very thin line between the best tube offerings and the best SS ones at this price point. 

I suppose one could consider the speakers and cable as a part of a "sub-system" that would include the amp. Depending on that system, the excellent mid range performance you are seeking might take some experimentation. McCormack/SMc can help guide you. I would suggest the DNA series which can be tailored and upgraded as your needs change. McCormack have refined a fundamentally and technically sound design over a long period of time. I have not heard every SS amp, but I do not recall
any over the past 30 years that sounded "better."
You could go with a tube amp, but that can be costly over a period of time with necessary tube replacement. Good luck, happy listening!