Tube Power Amp Reviews

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.

Although I retain a firm hold on the established audio world, and recognize and value all that it has achieved, I feel inexorably driven to make some space in my life for single-ended amplifiers—more especially, those that eschew negative feedback (footnote 1). A classic if costly example of the art is the Cary CAD-805C, which, to my ears, has earned the right to teach audiophiles what negative feedback really sounds like, and what damage it can do to the musical message when poorly handled. This shouldn't be taken as an out-of-hand dismissal of those many great pieces of electronics and amplification that use negative feedback—it is simply an acknowledgment, or even an assertion that negative feedback generates a sound of its own.

It's been 10 years since Balanced Audio Technology (BAT) introduced their first products: the VK-5 line-stage preamplifier and the VK-60 power amplifier. (I reviewed both in the December 1995 Stereophile, Vol.18 No.12.) The success of these and other BAT products has allowed designer Victor Khomenko (the "VK" of the model designations) and partner Steve Bednarski to quit their day jobs at Hewlett-Packard; they were joined by Geoff Poor as a partner to handle the sales end of the enterprise. BAT's current lineup includes several preamps, phono stages, a CD player, and tube as well as solid-state amplifiers. The top of BAT's preamp range is the VK-51SE, which costs $9000; their top tube power amp is the VK-150SE monoblock ($17,000/pair); if you want their best phono stage, the VK-P10 will set you back $8000.

At the last few audio shows, whenever I heard a pair of the big Cary CAD-1610-SEs, I fair licked my chops. The two-tiered monoblock looked positively stunning in black and polished aluminum, exotic tubes bristling from the top "floor" of its two-story edifice. The Cary always induced pelvic tilt in me—you know, when your lizard brain takes over and tube lust is in the air.

Some audiophiles tend to get a mite sniffy around those of us who have expensive tastes and limited budgets. I've always been willing to spend the price of a new car on a set of speakers, but I never had the cash or credit. The sonic virtues of hefty, high-powered Krells and wondrous, single-ended tube designs always enchanted me, but when you're raising a family you make do. Through my experiences in a high-end audio establishment I learned the metaphysics of mixing and matching as befits my lowly caste, and I gradually developed sophisticated reference points, so that as the years swept by I managed to inch my way up the aural food chain.

The VTM200 is the first Audio Research power amplifier I've reviewed. It took me 13 years, and ultimately I'm glad I'd put that much mileage on my reviewing odometer before tackling what turned out to be a most difficult assignment.