Tube Preamp Reviews

Sometimes, a product review in Stereophile can breed additional reviews. Shortly after I reviewed the Audio Valve Conductor line stage in the July">http://www.stereophile.com/tubepreamps/audio_valve_conductor_preamplifi… 2009 issue (Vol.32 No.7), I was contacted by NAT's US distributor, Musical Sounds: "Hey, if you liked the Audio Valve Conductor [$13,995], you'll love the NAT Symmetrical line stage at $8000! Would you like to review it?" Aside from Michael Fremer's review of the battery-powered NAT Signature Phono stage in the July 2007 issue, I was unfamiliar with this Serbian maker of tube electronics. But "Sure," I replied; "why not?"

Musical Fidelity's Tri-Vista kWP, introduced in 2003, was an impressive, high-tech, "statement" audiophile preamplifier. Its outboard power supply weighed almost 56 lbs—more than most power amplifiers—and its hybrid circuitry included miniature military-grade vacuum tubes. As I said in my">http://www.stereophile.com/solidpreamps/104mf">my review of it in the January 2004 Stereophile, the kWP's chassis and innards were overbuilt, the measured performance impressive, and any sonic signature imposed on the signal was subtle and, essentially, inconsequential.

"Are You a Sharpener or a Leveler?" was the title of my "As">http://www.stereophile.com/asweseeit/are_you_a_sharpener_or_a_leveler">… We See It" in the February 2009 issue. The terms sharpening and leveling come from work in the field of perception by the early Gestalt psychologists, sharpening referring to the exaggeration of perceived differences, leveling to the minimization of those differences.

You know me. I'm not perzackly an audio slut, but I am easy. When Audio Advisor's Wayne Schuurman called me to pitch the Vincent KHV-1pre tube-transistor headphone amplifier, he pretty much had me at "tube" and "headphone." But I wasn't familiar with Vincent Audio.

If any single link in the audio chain should be free of sonic personality, it's the preamplifier. Though a preamplifier's basic job description is "source selector with volume control," from hi-fi's earliest days preamps have been the designated dashboard: the more dials, switches, and lights, the better. All that control came at the cost of quiet, transparency, and tonal neutrality. Still, the quixotic quest for the mythical "straight wire with gain" continued to lead to minimalist designs, including impractical unbuffered "passive" preamps, in which cable length, thus capacitance, affected frequency response.

I've long admired Vacuum Tube Logic's line of amplifiers and preamplifiers. Owners Luke">http://www.stereophile.com/interviews/153">Luke Manley and his wife Bea">http://www.stereophile.com/interviews/607vtl">Bea Lam routinely appear at the Consumer Electronics and Home Entertainment shows with luxurious, microprocessor-controlled tube gear, soothing new music, good-sounding rooms, and a friendly, unhurried manner. Their show setups are dialed in so well that I often find myself taking refuge there, sitting and listening for hours with other Stereophile writers.

In any category of product or service, there is a gold standard—one company that epitomizes the best in its field of endeavor. Consider the Rolex watch, the Ferrari sports car, the Steinway piano, the Dunhill pipe. All of these artisanal manufacturers have spent decades, even centuries, earning their names' cachet with their histories of consistent excellence. While high-end audio boasts no names with a 60-year pedigree, such as Ferrari's—much less Steinway & Sons' +150 years—there is one firm whose storied past stretches back to the very emergence of the concept of high-end audio itself: Audio Research Corporation.