Solid State Preamp Reviews

Each equipment report in Stereophile focuses on a single audio component. When listening to a component for review, I leave unchanged all other components in my audio system. Other Stereophile reviewers experiment with different interconnects, speaker cables, power cords, or stands. As I found while reviewing Bryston's BP-17³ (Cubed) preamplifier, being flexible has its rewards.

Description
My first lesson in flexibility was learning what Bryston means by "Cubed" (footnote 1). Jim Tanner, Bryston's VP of sales and marketing, explained that all their Cubed models employ an array of 12 active devices for the first 6dB of gain. Developed by the late Dr. Ioan Alexandru Salomie, this array acts as "a super-linear" input buffer to filter out audio- and radio-frequency noise, particularly anomalies that originate in the power line, reducing the overall noise and distortion to less than 0.001%.

I have not been attending audio shows as often as I used to, and this January, for the first time in more than 20 years, I'm skipping the annual Consumer Electronics Show. My personal return on investment has become hard to justify, especially when attendance at each annual CES requires a round trip from New York City to Las Vegas, Nevada. More important, audio shows now seem focused mostly on either two-channel music playback or multichannel home theater, whereas what interests me is listening to music in surround sound.

The Mark Levinson No.526 is the first preamplifier designed by a new 12-person team led by Todd Eichenbaum, director of engineering at the Harman Luxury Audio Group's Engineering Center of Excellence (ECOE), in Shelton, Connecticut. Designed to fit the price niche between the company's least and most expensive preamps—the No.326S ($10,000) and No.52 ($30,000)—the No.526 costs $20,000.

Transparency is a trait we all value in a hi-fi rig, and it's a concept I've long thought I understood. A system that tosses up the illusion of a clear, spacious soundstage, on which you can hear—almost see—all of the singers and/or instruments, from side to side and, especially, from front to way, way back: that's the ticket. Still, although such transparency is a sign that you've entered the realm of fine sound, it's not an absolute requirement. Tonal accuracy, dynamic range, a certain thereness that conveys the emotional heft or delicacy of music—those things come first. Without them, the most precisely delineated soundstage is like an architect's sketch of an oil painting.

The experience left me doubting my ears. After I'd performed all the measurements of Ayre Acoustics' KX-R preamplifier ($18,500) to accompany Wes Phillips's review in our November 2008 issue, I spent a weekend listening to it. To my astonishment, the sound of my system with a Transporter D/A processor feeding the preamplifier was better than when the DAC fed the power amplifier directly. Through the KX-R, images sounded more tangible, and the sound was better focused, despite the signal's having been passed through not just another set of interconnects but also through the preamp's input and output socketry, switches, a volume control, printed circuit-board traces, and active and passive parts. Logically, you'd think that having nothing in the signal path would have less of a degrading effect than so many somethings. But no, that was not what I heard, much as I would have preferred otherwise.

Asked how to make a guitar, the celebrated luthier Wayne Henderson offered a straight-up answer: "Just get a pile of really nice wood and a whittling knife. Then you just carve away everything that isn't a guitar." (footnote 1)

The making of a preamplifier seems more or less the opposite. You start with a simple volume control and a couple of jacks, then add whatever you think constitutes a preamplifier. Choices might include electronic source switching, line-level gain, phono-level gain and equalization, tone controls, tone-defeat switches, a balance control, a headphone jack, an iPod input, and maybe even a digital-to-analog converter with a USB receiver. The sky is pretty much the limit.

In the early 1970s, Stereophile's founder, J. Gordon Holt—a man I used to describe, with all due respect, as having been clothed by the haberdasher to the homeless—said that Audio Research's SP-3 tubed preamplifier was "the closest thing available, in fact, to the ideal straight wire with gain" ie, it would amplify the signal without editorializng in any way. Back then, the SP-3 cost $595. Today it would cost around $3500. But TAD's C600 dual-mono, solid-state, balanced preamplifier costs more than 10 times that: $42,000.