If you listen mostly to classical and jazz, I recommend that you give the Solo 575s a listen—but proceed with caution. And if you listen mostly or exclusively to rock, and your speakers have good bottom-end extension, and—especially—if they thrive on lots of power and can deliver wide dynamic swings, you need to hear the Solo 575s. Just don't expect the usual buttery class-A sound: However well Krell's iBias circuit works to increase efficiency and thus decrease heat, it melts away some of that butter. Which is what left me wondering if iBias results in true class-A operation—or class-A*.

Spending $17,500 on a pair of mono-block amps is a lot, but the Solo 375 delivers a lot. It combines a very smooth, un-solid-state, un-hifi sound with loads of power and dynamics, plus a design that works great whether you're plopping the amps on the floor by the speakers or shoving them out of sight into a closet or equipment cabinet. In fact, I'd go so far as to say I've never encountered another amp that combines the Solo's 375 warm, wonderful, involving sound with such a practical and versatile design.