Like everyone from home builders to automobile makers, stereo designers have not been immune to the temptation of supersizing their products. From 150-pound amplifiers to ninefoot-tall loudspeakers, it almost seems as though audio manufacturers are trying to engage the muscles of their prospective clients as much as their hearing.
But just as slumping SUV sales have pushed car makers to rethink their direction, an intriguing development in high-end audio has led to a return by some manufacturers to the “small is beautiful” mantra. The 200-watt Nagra Pyramid monoblock amplifiers, which hail from Switzerland, are a case in point. Like many of the Class D switching amplifiers that have appeared in recent years, the Nagras (which are not switching amplifiers) are diminutive, run cool, and promise to pack a wallop belying their size.
When John R. Quick, Nagra’s astute and experienced sales and marketing manager, dropped the amplifiers off, he barely needed my assistance schlepping them in. You could almost hold one of the Pyramids in the palm of your hand. Still, the appearance of the Nagras is inevitably going to be an issue. This is a love-it-or-hate-it design. The pyramidal shape was developed to allow all four sides of the amplifier to operate as a heatsink. No matter how hard I pushedthese amplifiers, I could barely get them to become warm to the touch. The amplifier also sports blue LEDs that flash in brightness proportionate to the amount of power the amplifier is generating. Red, which I only managed to trigger once, signals that the amplifier is clipping. If the amplifier is unduly stressed, it will terminate operation before the loudspeaker is damaged.
Learning that I own Magnepan MG 20.1s, Quick called Magnepan’s Wendell Diller before heading over to my place. Although he was a little nervous about the power requirements of the speakers, the Nagras were easily up to the task of driving the 4-ohm resistive load presented by the 20.1s. The PMA boasts sufficient power to drive the Magnepans and deliver a healthy amount of voltage. But because I enjoy bi-amping, we added a stereo PSA to power the Maggies’ bass panels. (One interesting thing I learned from the flashing lights is that Maggies’ ribbon tweeters appear to soak up more power than its bass panels.)
The technology inside the $10,995- per-pair Pyramid is as unusual as the speaker looks. Drawing on Nagra’s nowdiscontinued MOSFET power amplifier, it uses a switching power supply as well as a patented Power Factor Corrector to allow it to use a mere two—two!—output devices to deliver 200-watts into an 8-ohm load. As seasoned audiophiles know, matching transistor output devices is something of a nightmare for equipment designers. The more output devices a designer uses, the more current an amplifier can deliver. But the trade-off is in having to match the output devices. It seems almost impossible to get transistors to work together perfectly, which is one of the reasons that tube aficionados like to grouse about a slightly hard, less than euphonic “transistor” sound.
The Nagra has none of that hardness. This is Swiss engineering to the max. Seldom has a solid-state amplifier possessed this kind of silkiness. When I first heard the Nagras on the Magnepans, it was with something of a gulp. My initial thought was that they sounded less etched than the Classé Omega monoblocks, which are some of the best solid-state amps I’ve ever heard. These unflappable amps are more powerful, go deeper, and throw up a bigger soundstage than the Nagras. They also cost three times as much. And while the Nagras don’t wimp out on rock music, they aren’t really designed to drive most loudspeakers to ear-shattering levels. They specialize in something else—intimacy, purity, and clarity.
Take, for example, the much-heralded Magnepan ribbon tweeter. This revealing transducer—some would say excessively so—sounded close to flawless through the Nagras. There was never even a hint of shrillness, whether it was female vocals or a scorching jazz trumpet—except when the recording itself was flawed. The Nagra was also no slouch when it came to bass. I was mightily impressed by its pitch definition, most notably on Linda Ronstadt’s affecting CD of Mexican folk songs, Canciones de mi Padre [Asylum], where the bass notes, perhaps a little wobbly with tubes, snapped into place as smartly as a military salute. And Ronstadt’s voice never sounded less than immediate and soaring. The Nagras don’t obtrusively remove veils from the music; they make music sound as though the veils never existed in the first place.
Throughout, the sound of the Nagras is distinctly on the cool rather than the warm and lush side. One might, at times, wish for a bit more harmonic richness. The VTL 750 amplifiers, for example, slather on layer after layer of overtones, particularly in the bass. The Nagras don’t. This raises an interesting dilemma. I suspect that one reason that Class D amplifiers have evoked so uchcontroversy in the pages of this magazine is because of a silvery sonic signature that I associate with switching amplifiersand, perhaps, amplifiers that have switching power supplies, like the Nagra.