Tube Power Amp Reviews

Ars-Sonum is a Spanish audio company that, as far as I can tell, makes only one product—but it's a doozy (footnote 1). The Filarmonía SE is a tube integrated amplifier that is, in many ways, an homage to Dynaco's iconic Stereo 70 power amplifier of 1959, but the Filarmonía is by no means a slavish copy. Get down to specifics, and it's actually more of a clean-sheet-of-paper design.

When I attend Stereophile's annual Home Entertainment show, I rarely sit and listen to music for very long. Instead, I try to hit every room, press the flesh, find out about new products, and play a little jazz.

Today is Monday, February 5, and it's so buttercupping cold outside that the custodian couldn't get our school's oil burner started. Consequently, my daughter is home for the day, playing on the rug in front of the fireplace. (Santa brought a wooden castle and a fine selection of medieval figurines, some of which are headed for the dungeon as we speak.) I'm at my desk in the music room, on the upwind side of the house—and the wind is murder. The west wall is cold. The north wall is cold. The floorboards are cold. But the air inside is warm as toast: I'm driving my Quad ESL speakers with a Joule Electra VZN-80 amplifier ($12,000) that isn't at all bashful about squandering a goodly amount of energy as heat. I can't think of a more delightful quality for an amp to have, at least on a day like this.

When I unpacked the Rogue Audio Atlas, I didn't know how much it cost. After examining its chassis of high-grade steel, its silver-anodized aluminum faceplate, its sleek and slightly rounded edges, and, above all, its two chunk-o'brick transformers—for such a little thing (a foot-and-a-half square by half-a-foot high), it's heavy—I guessed around five grand. Then I called Rogue Audio and learned that it retails for $1395.

Everybody loves a bargain. No—make that: Most people love a bargain. Some just want the best, and they don't care about the cost. Some even distrust and reject out of hand any product that's not expensive enough. If you're one of these people, you might as well stop reading this review right now—the PrimaLuna ProLogue Three and ProLogue Seven are not for you. $1395 for a tube preamp? $2695 for a pair of 70Wpc tube monoblocks equipped with four KT88 tubes each? Must be based on old designs in the public domain using cheap parts carelessly assembled...

In this hobby, nothing's for nothing. To get that gorgeous midrange, with its harmonic depth and inner detail, tube-amp enthusiasts are willing to give up some things in the bass. Tube folks put up with heat and occasional maintenance—routine or otherwise. To get the ideal middle, fans of single-ended triodes are even willing to shave off considerable dynamic range and settle for ultra-efficient speakers that often have limited response at the frequency extremes. Those who say nothing is lost by preferring tubes are in denial.

Just who does Bruce Rozenblit think he is? And why is he saying those things about the late Julius Futterman? Rozenblit, relying heavily for guidance on his Electrical Engineering degree, has crafted an OTL (output-transformerless) amplifier that flies in the face of contemporary design dogma. To hear Bruce tell it, he's tamed the breed—this is how OTLs should have been done to start with, Futterman notwithstanding.