Solid State Power Amp Reviews

Audio reviewers are kinda slutty. Not sexually, of course, but in the way we promiscuously go through equipment. Like the most popular girl in school, or Tiger Woods, we have our choice of any hot thing we want, whenever we want it. Heck, reviewers don't even have to pick up equipment at bars or clubs: the stuff is delivered right to our homes. We use the gear for a few months, then send it packing once the next hottie comes over to play in our room.

On the face of it, the power amplifier has the simplest conceptual task of any audio component. Fed an audio signal at its input, all it has to do to satisfy the demands for current made by the loudspeaker is to modulate a high-voltage voltage supply with that signal. Yet power amplifiers vary enormously in their ability to perform that task without editorializing. As a result, when I find an amplifier that appears to step out of the way of the music in the manner I desire, I make the commitment, I buy it, and I stick with it.

When Philip O'Hanlon of On a Higher Note, Luxman's US distributor, delivered the B-1000F monoblocks, it took three of us to wrestle their shipping crates into my house and then into the listening room. Once they were unpacked, it still took two of us to maneuver each of them into position—at 141 lbs and 16.9" wide by 11.6" high by 23.3" deep, the B-1000F is far from easy to shift. Fortunately, O'Hanlon had also brought along a pair of Stillpoint stands specifically made for the Luxmans; the B-1000Fs certainly wouldn't have fit into my equipment racks. (The Stillpoints are lovely things. I recommend 'em if you go for the B-1000Fs.)

When O'Hanlon told me the price of the stands—$2500/pair—I asked what the amps cost.

"Fifty-five," he said.

"You mean the stands are 45% of the price of the amps?"

One of my favorite parental duties is dispensing advice that's calculated to make me sound wiser than I am. Among those pearls: Every so often you should change your point of view—your philosophies—just to see if your opinions can stand the strain. In doing so, you may discover a few things that are better than you expected them to be!

James">http://blog.stereophile.com/ces2009/now_thats_what_i_call_music">James Bongiorno, the engineer behind the Sumo Andromeda, has enjoyed a long and colorful career as an audio amplifier designer. He has cast himself at times as an enfant terrible, exploding at audio critics and running scandalous advertisements (footnote 1). His best-known amplifier is the Ampzilla, produced by Great American Sound, but he also designed the Dyna 400. Currently Jim is living on a boat and serving as part-time consultant to the Sumo Company.

A decade ago, many predicted that amplifiers with switching or class-D output stages would come to dominate high-end audio. In a post–Peak Oil world in which the price of energy would always continue to rise, a class-D amplifier's very high efficiency in converting AC from the wall outlet into speaker-driving power would be a killer benefit. Although a conventional push-pull class-B amplifier has a theoretical efficiency of 78.5%, which would seem usefully high, this efficiency is obtained only at the onset of clipping; the need for the output devices to carry a standing bias current reduces that efficiency considerably, typically to around 50%. Class-A amplifiers are even less efficient, with a maximum of 25%; ie, three times as much power is dissipated by the amplifier as waste heat as is used to drive the loudspeaker (see "Sam's Space" in this issue).

Some time ago in these pages, Anthony H. Cordesman observed rather ungraciously that the whole line of Hafler electronics "could do with reworking." This was interpreted by many readers—including the good people at the David Hafler Company—as meaning that AHC felt the entire Hafler line to be mediocre. In fact, he does not. (He had given a Hafler product a positive review a few issues previously.) Tony's comment, however, did express a sentiment that most of us at Stereophile have shared for some time: a feeling that Hafler products had slipped from the position of sonic preeminence which they enjoyed during the 1960s and '70s to one of mere excellence in a field where only preeminence is acclaimed.