Tube Preamp Reviews

If I had to pick one amplifier designer as having had the greatest continuing influence on the high-end market, as much as I admire John Curl, Audio Research's Bill Johnson, and Krell's Dan D'Agostino, the name of David Hafler inexorably springs to mind. Not because he challenged the very frontiers of hi-fi sound, but because he combined a fertile, creative mind (footnote 1) with a need to bring good sound to as wide an audience as possible, both by making his products relatively inexpensive and by making them available as kits. (The Major Armstrong Foundation apparently agrees with me—they presented David with their "Man of High Fidelity" award at the summer 1988 CES.) It remains to be seen if the Hafler company will continue in this tradition, now that David has sold it to Rockford-Fosgate. But there is no doubt that many audiophiles were first made aware of the possibilities of high-end sound by Hafler products in the late '70s, and by Dynaco in the '60s.

It takes more than passing courage to make another assault on building the world's best tube preamplifier. You face stiff competition from well-established firms like Audio Research, Conrad Johnson, and Counterpoint. Such units can't be made inexpensively, and you face the steadily growing problem of tube supply: it is getting harder and harder to get tubes that are stable, have predictable sound and performance characteristics, and are long-lived. And you have to show audiophiles who have been burned before that you will still be around when they need service.

In appearance the Counterpoint SA-7 tube preamplifier is quite attractive, possessing the thin, low-profile look currently in vogue. There is a mute switch which (if you remember to use it) protects your amplifier from the preamp's turn-on and turn-off thumps. Unfortunately, the volume control on my unit didn't track accurately, and it was necessary to adjust balance with each change in volume. One unusual feature: the balance control allows very fine gradations in balance adjustment (a large movement of the control results in a small change in balance).

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.

It says something for the state of technology that, after a quarter of a century, there still is no authoritative explanation for why so many high-end audiophiles prefer tubes. Tubes not only refuse to die, they seem to be Coming back. The number of US and British firms making high-end tube equipment is growing steadily, and an increasing number of comparatively low-priced units are becoming available. There is a large market in renovated or used tube equipment—I must confess to owning a converted McIntosh MR-71 tuner—and there are even some indications that tube manufacturers are improving their reliability, although getting good tubes remains a problem.

Several issues back, we reviewed rather enthusiastically a pre-production prototype of this preamp. The original was an unprepossessing-looking device on two chassis, interconnected by a 3' umbilical, with a squat little preamp box and an even squatter power supply with humongous cans sticking out the top. We averred that it sounded nice. The production model is so nicely styled and functionally smooth that we wondered if it might not be another Japanese product. 'T'ain't.