Robert Gallien is a Stanford educated engineer who first began making amplifiers in the late 1960s, while working a day job at Hewlett Packard in California. These first amplifiers had the GMT brand name, but in the early 1970s Gallien joined forces with another HP engineer Richard Krueger and the company became Gallien-Krueger. Gallien-Krueger are best known for their bass amplifiers and stopped producing guitar amplifiers all together in the late 1990s.

Source: Gallien-Krueger website (5 July 2017)