- solid state amplifiers
Haynes amplifiers were made by the Amplifier Corporation of America (ACA) a company established in 1936 and specialising in broadcast and amplification systems. The amplifiers were designed by Nathan M. Haynes - who held various patents related to amplification and recording circuits. Unicord bought ACA and the Haynes brand in the early 1960s. By 1966 there were two Haynes amplifier models: the Jazz King and the Bass King. Both were solid state combo amplifiers.
Source: Haynes Amplifiers - Unicord catalog 1966