PS Audio BHK Signature 300 monoblock power amplifier

Was it more surprising that, in 2015, PS Audio would produce a monoblock class-AB power amplifier containing vacuum tubes, or that PS Audio would release a monoblock power amplifier at all? I'm not sure.

In 1974, Paul McGowan and Stan Warren founded the company to produce and market a standalone phono preamplifier, sold directly to consumers for $59.95. From there they naturally progressed to a series of line-level preamplifiers. Toward the end of the '70s, PS Audio produced the Model One, the company's first power amplifier. In the mid-1980s came the high-performance, moderately priced ($495) 4.5 and 4.6 preamplifiers. I reviewed—and bought—a 4.6 a few years after I began reviewing gear for The Abso!ute Sound; Tom Norton reviewed the 4.6 for the September 1988 issue of Stereophile.