In early 1963, the Kingsmen, a band based in Portland, Oregon, became known for their hit version of the song "Louie, Louie". After its hit single, the band soon embarked on a 50-state national tour. Because the band was used to playing small hops and school dances, many of the members found themselves ill-equipped with the amplifiers that they were currently using. Bassist Norm Sundholm discovered that his bass amp was not nearly powerful enough to play larger concert halls.
Sundholm enlisted the help of his brother Conrad to help solve his problem. By 1964, the Sundholm brothers had designed a high-powered concert bass amplifier. By 1965, the demand for Sundholm's amplifiers had increased to the point where the family garage could no longer be used as the manufacturing facility. Thus, the Sunn Musical Equipment Company was founded.
The band Sunn O))) was named after the company (to the point of including a typographic representation of the logo) and Gross National Productions who were the East Coast promo band for Sunn amps in 1971.
Sunn was ultimately acquired by Fender, which discontinued production in 2002.