Amplifier designers have frequently looked for ways to marry the advantages of tubes to those of solid-state devices. Hybrid designs of various stripes have appeared over the years, most of them using tube input stages with transistor output stages, eliminating the major weaknesses of tube amplifiers: eg, they run hot, are unreliable in that tubes have a finite life, are more expensive than a similarly powerful solid-state design, and have power-hungry output tubes and output transformers.

In the September 1988 issue of Stereophile, I wrote a rave review about the first speaker, the AE1, from what was to me a totally unknown English company, Acoustic Energy. Though tiny, and possessing an intrinsically limited low-frequency response, the $1500/pair AE1 was one of the most musical loudspeakers I have ever used, throwing a deep, beautifully defined soundstage, and possessed of a clean treble and a sweet, if rather forward-balanced, midband.