Warm sounding amp to a mixer

First thing I would do on your Klipsch is to take out the Traxtrix horn and apply dynamat to the back side of the horn itself.  Also apply dynamat to the back of the horn/tweeter driver.  This should really cut down on the tweeter resonance and help control the high frequencies properly (actually, I'd recommend this for any horn-based speaker).

If that doesn't fix your problem, then I would agree on the B&K amp suggestion.  I had a B&K 200.5 amp and it was very warm (the standard B&K signature, I believe).  It had very forgiving highs, but it was just too warm for my tastes.