100W+ solid-state amps known for beautiful mids

Chord Electronics SPM 1050 or 1200C (both in MkII versions) - Chord provide amplification to the Royal Opera House, Convent Garden - not heard the new "Ultra" series but, many on the second-hand market as Chord fans upgrade to "Ultra". Should work well with ATC's.

Conrad Johnson MF2100

+1 for darTZeel.

very low noise, no global feedback, minimal parts count in the signal path, swiss built like a tank.

darts don’t sound solid state, and don’t sound like tubes, they sound like music.

3 years ago i brought 2 really spendy tube amps into my system, the Lamm ML3 mono’s and the VAC Statement 450 mono’s and compared them for 4 months, to my darTZeel mono blocks. preferred the timbre and textures, realism and transparency of the dart and those went away.

your OP does not specify price range only mentions $5k related to the Quad amp. you can find used darTZeel 108 stereo amps in the $8k-$14k range. the newer 108 Mk2 version lists for around $40k. the Mk1 versions with the SNCP upgrade are better dynamically....most have been done. and that early version of the 108 has the super pure and harmonically complete mid range, and amazing soaring sweet highs no other solid state can quite touch. and if you value a grainless and liquid musical viewpoint, no solid state is in the league of the darts.

@blackbag20 A difference of philosophies, I reckon. I'm of the opinion that everything is coloured. "Wire with gain" doesn't exist in my books. To me, it's all about mixing and matching components to offset weaknesses and create synergistic sound. 

should the list include amps currently in production?