stukje van stereophile...
"And have I got an amp to tell you about! The mother lode of Krell amplifiers has arrived, and its name is the KSA-250. If the KSA-50 had the weight of a steamroller, this one has the impact of an atomic bomb. Krell amplifiers have always been known for their superb stability and bass control, but have been, in my opinion, somewhat short in the department of musical finesse. Of course the KSA-100 and -200 and the KMA-80 and -160 were superb amplifiers, but there were competitors who gave up very little in the bass region and offered much more harmonic and musical honesty. In this respect, the KSA-250 is a landmark product for Krell; unquestionably their most refined amplifier to date, and possibly the most successful blend of solid-state and vacuum-tube virtues to come down the pike. No, it doesn't do everything perfectly, but in terms of overall sonics, and especially price/performance ratio, it's a winner.
This amp draws an enormous amount of current (12A continuous, a not so pleasant side-effect of class-A operation), and should be, according to Krell, placed on its own dedicated 20A AC circuit
Now comes the KSA-250, and a whole new ballgame. I am a musician, not an engineer, so I can't tell you in technical terms what Dan D'Agostino has done to design such an incredible amplifier. What I can tell you, however, is that it is the most musically convincing product of its type to hit my ears, either tube or solid-state. While the Jadis tube amplifiers surpass this product (or any others, for that matter) in harmonic honesty, I don't know of anything else, for any price, that offers such a natural musical presentation. Gone is the sectionalized bass/midrange/high-frequency Krell trademark. Total integration from top to bottom has now been accomplished, but not at the expense of that wonderful Krell clarity and impact. One might describe the overall sonic signature as almost tubelike, while retaining the attributes of the finest solid-state designs.
In direct comparison with my reference Mark Levinson No.23 amplifier, the KSA-250 wins in all categories, except possibly for the 23's uncanny ability to specify the leading edges of instrumental and vocal attacks. While the KSA-250 dynamically eats the No.23 for lunch and spits out the bones, it does not give me as much "you are there" feeling with the performers on stage. In this respect, the No.23 offers a more hands-on perspective (which some members of the Stereophile staff call "forward"), but, at the same time, is not nearly as dynamically realistic. While soundstaging with the ML No.23 is excellent, it is totally outclassed by the KSA-250. In fact, with the recent arrival of the spectacular B&W 800 Matrix monitors, I can hear the vertical and horizontal edges of the No.23's soundstage, in comparison with the much more open and realistic three-dimensional image projected by the KSA-250. The No.23 sounds almost "small" (it isn't) in comparison, compressing the outer edges of the orchestra into a more constricted frame than the KSA-250. The immediacy of the No.23 still appeals to me, but the Krell is definitely more neutral, harmonically accurate, naturally spacious, more extended on top and bottom (the legendary Krell bass), and, last but certainly not least, more dynamic. The No.23 is certainly no wimp, but it does appear to run out of gas on full orchestral transients when compared to the KSA-250.
The term "awesome" is definitely overused nowadays. But I can't think of another way to describe the KSA-250's sound: a huge soundstage, far exceeding the lateral and vertical speaker boundaries, with a breathtakingly natural sense of depth. So clear, so open, so transparent, so powerful, yet so refined. The sense of reserve power is immediately obvious to the listener, but not in the same way one would normally associate with such an enormous amount of stored energy. This amplifier does the best job, so far, of reproducing the realistic size and dynamics of a live symphony orchestra in my listening room. Yes, the No.23 is excellent, but until you've heard the KSA-250, you haven't heard real dynamics. A perfect example is the beginning of Eliahu Inbal's performance of Mahler's Symphony 5 (Denon CD CO-1088). The visceral weight coming out of the 800 monitors at that first orchestral climax was closer to the real thing than I ever thought possible. Compared to this, the No.23 came off sounding like a peashooter.
Conclusion
The Krell KSA-250 is a truly extraordinary piece of audio equipment. It is ruthlessly revealing of everything upstream and is, in this respect, the finest reference amplifier currently available. It will drive virtually any load, and is the first amplifier this listener has heard that successfully combines ultimate musical finesse with sheer dynamic brawn without sacrificing much along the way. While the KSA-250 does not quite measure up to the finest tube electronics in the area of harmonic accuracy, and falls somewhat short of the best solid-state in the ability to resolve vocal and instrumental attacks, it wins the prize in overall musical and sonic honesty. But if you're thinking about buying one of these, be darn sure that your front-end electronics are the very best, or else you may be disappointed.
If you're in the market for a great amplifier (or even if you're not), you owe it to yourself to audition the KSA-250. It doesn't get much better than this, folks, so find the checkbook, put off painting the house until next year, and get to your local Krell dealer. Now, how am I going to explain to my wife that we need to buy a new amplifier...?—Lewis Lipnick