Help me find a smooth solid-state amp?

Consider a tube pre like a CJ PV10, a great match for a bright amp if your Adcom is bright, I used to have a 555II and switched to a Classe 200, much smoother midrange and highs with plenty of punch. A much more refined sound. I still match it with a CJ pre 17. Before you make an amp change demo a couple of different front ends and interconnects like MIT or Cardas. Also try some damping material on your front wall between the speakers, could be anything like foam, a rug or wool blanket. Good luck.

The culprit in my experience is the adcom preamp. the amp is actually not that bright, but the preamp is. I had a gfa 5400 and a gfp-555 II (preamp) and with revealing speakers (in my case, castles) the sound was horribly bright, but with a passive preamp the sound was pretty good. BEFORE you switch amps, switch preamps. The c-j is a great suggestion. Or even a creek passive (much cheaper)

Check out the Meitner MTR-101 MkII monoblocks. These can be had used within (or less than) the price ranges of many of the better recommendations here. These will drive almost any speaker, have deep bass and are smooooooooth. I like higher powered tube amps with my current speakers but also really love these amps. I heard them most recently with Hales Trans 8's, which they drove beautifully. They don't take up too much space and are visually stunning in dark wood cabinets. If I had money to burn for an extra set of amps I would pick a pair and hang on to them. One of the least known best buys in high end sound.

P.S. Concur with the suggestions of also adding a tube pre-amp. Tube pre's and solid state power amps are generally a good combination -- took me to the next level when I added one to my "old" DNA1 Deluxe. You can also play with the tubes to signifcantly affect sound. Lots of very good values of the used market for tube pre's, including phono stage.

Djjp: Sorry I typed 500 and meant 300 hours above. Still quite a long time, though my little Castles took around 200 or so being played at lower levels.