FPB 600c

600 W, 1200 W, 2400 W (8, 4, 2 Ω)

Class Acir cuitry, CAST technology,

Sustained Plateau Bias II.

19 x 10.3 x 25.5 in.

48.3 x 26.2 x 64.8 cm

180 lb. / 81.8 kg
 

Although Krell has made preamplifiers almost since the company's inception -- and has built top-of-the-line digital components for more than a decade -- Krell's name and fame have always been exemplified by its amplifiers. Hulking constructions festooned with heatsinks and fronted by massive slabs of anodized aluminum -- the gold Krell name-badge screwed tightly down with its six signature screws -- Krell power amplifiers possess a macho mystique attained by only a handful of products. Just as Duesenberg lent its name to a type of superlative ("It's a doozie!") and another car marque, Cadillac, came to personify excellence, "built like a Krell" has come to symbolize engineering and construction quality in the world of hi-fi.

This is not to say that the company is without it critics. Krell amps are unabashedly expensive. Krell's brand of quality does not come cheap -- and yet, to criticize a Krell amplifier for being needlessly rugged or over-engineered is to miss the point. The point has always been to build equipment that CEO Dan D'Agostino likes -- and from the company's earliest days, D'Agostino has demanded that Krell's amps have tremendous transient response, almost limitless dynamic potential, the ability to drive impossibly difficult loads, and a sense of effortless power. And, not so coincidentally, D'Agostino likes nice things -- Italian suits, shoes, and cars; Swiss watches; and haute cuisine -- all areas where excellence has not been achieved unless the product also exhibits a certain sense of style. And all, need I add, areas where a product's expense merely adds a certain cachet.

On the other hand, Krell's biggest competitor may well be itself. No one who has ever bought a Krell amplifier has actually worn it out. The first ones made -- some 21 years ago -- are still working as well as they ever did and will continue to do so for another 20 years, whereas that fancy meal you ate at Daniel last night has probably already turned to, um, a memory.

Krell's amplifiers have always been based upon class-A operation, which is the most linear, lowest distortion operational mode. But there are inherent problems with class-A operation: The full current needed for full-power operation is continuously carried by the amp at all times, no matter what the signal actually requires. This is inefficient, delivering 10% or less of the amp's total power draw as usable power. The rest of that draw is turned into heat. Thousands of watts of heat end up being dissipated to create a few hundred watts of usable power. This means that class-A amps need huge cooling systems, usually either massive heatsinks or fans, or both, and these add to the amp's size and cost.

A simple solution to this is to bias the amplifier to operate in class AB, where the amp will operate at a much higher level of efficiency (possibly as high as 50%), which permits the amp to be smaller and requires less heat dissipation. The downside is higher distortion.