Tube Preamp Reviews

Once upon a time, all audio equipment used vacuum tubes. In recent years, however, tubes have become the exclusive province of super high-end audio. It is more expensive to accomplish any particular task with tubes than with transistors, and few manufacturers (with the exception of Conrad-Johnson) seemed willing until now to refine their techniques and pare back their budgets to make tube components more affordable.

In appearance Conrad-Johnson's PV4 is distinctly plain: a basic black and silver box with a few simple knobs and buttons. The controls are logically laid out, clearly labeled, and work properly. The two channels track well through the volume control, maintaining balance; pushbuttons and control knobs have a smooth, solid feel (except for the noises audible through the system when switching inputs). Don't forget the turn-on and turn-off thumps mentioned above; the PV4 is the only one of the preamps I review in this issue—the others are the Audible Illusions Modulus ($450) and the Counterpoint SA-7 ($595)—that lacks a mute switch.

In the March 2018 issue, Art Dudley admired the sound quality of Ayre Acoustics' KX-5 Twenty preamplifier, but didn't love some of its operational aspects. I've staged this Follow-Up as a putative face-off between the Ayre and my current reference preamplifier, the PS Audio BHK Signature, which I reviewed in the June 2017 issue.

Every day in my bunker, I use one of a few high-quality headphone amplifiers to double as a line-level preamplifier-controller and operate as the quality-assurance reference for my ongoing audio experiments. I must choose this component carefully, because it determines the upper limit of my system's ability to reveal any subtle differences among components under review.

In January of 2014, some of us wondered if the sudden death of designer Ken Shindo would spell the end of the company he founded in 1977: It was hard to imagine Shindo Laboratory being led by anyone but its founder, a former Matsushita engineer who made it his life's work to study not only the designs of audio's golden age, but to learn the sound of every vacuum tube, every passive part, every circuit variation that he might reasonably press into service.

Everyone knows that world-class analog and digital sources are the bedrock of all fine audiophile systems. Everyone also knows that a happy relationship of amplifier, speakers, and room makes audiophiles smirk Aren't I lucky? Fewer among us are aware that the upper limit of sound quality an audio system can deliver will be established by whichever audio contraption we use to select our sources and adjust their volume.

"Let be."

Those two words, from Shakespeare's Hamlet, express an entire philosophy of life in one of the shortest sentences possible. The quotation may not be familiar, but the concept certainly is—contemporary equivalents, each with its own inflections of meaning, include: Shit happens. Let the game come to you. Keep calm and carry on. (I hate that one.) Paul McCartney wrote something similar, and only slightly less concise, in a late Beatles song.