n the mid-1960s, as solid state amplifiers and acoustic-suspension speakers gained popularity in the US, low-power tube amplifiers and horn-loaded loudspeakers were abandoned. The recovery started almost immediately. Tube amps reappeared in the early 1970s, from Conrad-Johnson and Audio Research, followed by Cary Audio and others was reproduced by Harvey “Gizmo” Rosenberg of New York Audio Laboratories in the form of the Futterman OTL-1 power amplifier. Rosenberg’s hybrid tube/FET amplifiers and preamplifiers, and his gift for showmanship, made him a prominent audio influencer. Sumiko cofounder David Fletcher and Auditorium 23’s Keith Aschenbrenner imported tube amplifiers from Japanese brands, and in the early 1990s, Peter Qvortrup of Audio Note UK marketed his tube amplifiers in the US as luxury goods, paving the way for contemporary luxury audio.
