From High-End Audio:

COINCIDENT FRANKENSTEIN-
Update-Playing my Speakers "Full-Range"

Since I made some changes with the input impedance of the Coincident Frankenstein (and Dragon) amplifiers (by increasing it), I have finally been able to play my Pure Reference speakers full-range without the need for bi-amping and electronic crossovers. This just happened at the end of July, so I am still experimenting when I have the time and opportunity (no storms!). I haven't tried the Dragon yet, and I haven't played my most demanding recordings, but that will eventually come.

From what I have heard so far, with a decent variety of records, the improvement playing with a single amp has been close to a revelation of sorts. There's no question that the (Behringer) electronic crossover subtracts musical information and more. This is not surprising of course, since all electronics do some harm, but I had no other choice during these many years. Now I can't make a final evaluation and judgement until I hear more challenging recordings, but I feel, at this point, that for most listeners, and in most rooms, the Frankenstein amp can easily drive the Pure Reference by itself, with outstanding results, and without any serious compromises.