audio 1326 - I can comment on some of your possibilities.
I have used the CS2.2s since 1990 in all kinds of applications; I know them better than anything else. They are a target for my upgrade activities, so significantly improved performance will be gotten from them in the future.
At Thiel we had an original Bryston 3B (as well as its successors). I find it somewhat brittle despite its big bottom end. The STs are an improvement, and the 'cubed' series is first-rate.
The Denon is current-limited by definition - it does not double its output into half the load impedance. But as JA mentioned, Japanese made Denons have good bones. And theCS2.2 only drops below 4 ohms for limited time and has a very flat impedance curve, much gentler than later designs. So, it will work.
I like your Adcom GFA555 much better. The earlier Japanese boards use a higher quality transistor shared with the GFA535. Nelson Pass's designs have simple circuitry dependent on high parts quality. I have two of these amps and the earlier (Japanese) has a distinctly cleaner sound. The GFA555 (straight, series I) can be upgraded by Jim Williams of Audio Upgrades in Carlsbad CA at two levels-the higher using film resistors. The upgraded units punch way beyond their price class. I use a pair in bridged mono configuration as part of my listening and test setup.
