i have heard very little about krell on this forum, so i assume its not all that popular in the DIY community. i got to go to a special invite training through krell today conducted by the VP of sales today.
it was actually VERY insightful. im not a fan of krell, but they have their act together, and it was very cool to hear some of the things they do with their amps. their DC speaker protection circuits, current mode circuits, and balanced circuitry sounded very nice on paper. the result in sound was pretty darn nice too.
the thing i was most impressed with was their new EQ setup for their showcase processor. you were able to fully shape the frequency respond of the amp using notch, high-pass, low-pass, shelf, etc, filters within a 0.4 octave tolerance (+-1dB). as a test, we did a high pass filter at 800hz with the highest "settings". it make is sound like bose, but, didnt lose any clarity, didnt diminish any tonal qualities or degrade the sound that wasnt filtered in ANY way. pretty impressive as far as EQ's go.