Benson Electronics Inc was a Californian company active in the 1960s and early 1970s that made guitar amplifiers. The company was founded by Ron Benson, who was a studio guitarist as well as an amp designer. In the early 1960s, striving to replicate the sound of Howard Robert's Gibson GA50 amp, Benson decided to learn electronics and make one himself. Benson ended up also making one for Howard Roberts. This amp became very popular with studio players in Los Angeles. As a studio amp that was often used by numerous different instrumentalists, Benson designed them to be flexible with a plug-in module which could shape the tonal characteristics for each instrument. Therer were six of these Benson Equalizers, which were a small round component which plugged into the back of the amplifier giving 6 different sounds

Ron initially manufactured the amps in his garage, but eventually had to outsource production to the Dr. Henry L. Richter Corporation of Monrovia, California. This  lasted for several years until the Richter Corp. went bankrupt.  Then the L.D. Heater Corporation of Seattle,  manufactured the Benson amps. This company closed about 1974 and with it ended Benson amplifiers. Around 2000 Benson amplifiers were made in total.

Source History of Benson Electronics