Marshall Bluesbreaker - Description, Specifications and Sound

Description, Specifications and Sound

Marshall's original Model 1961 and 1962 were basically JTM 45 combo amplifiers. Model 1961 was essentially the lead version of the Model 1987 JTM 45, fitted with tremolo and installed into an open backed speaker cabinet, while Model 1962 was the bass version of the JTM 45 (Model 1986), also fitted with tremolo and open backed cabinet. These amplifiers both feature the basic JTM 45 modified Fender Bassman circuit, which provided the origin of what became known as the "Marshall sound". The first versions of these combo amplifiers were made in 1964-1965, with Models 1961 and 1962 being fitted with 4x10" and 2x12" Celestion speakers respectively. An extremely rare 2x12" extension cabinet was also offered. A later model had a slightly thinner cabinet with different acoustics. Production JTM45 amplifiers used KT66 output tubes, which are credited with providing "a round, bell like tone with soft distortion character." Also contributing to the overall sound picture of the JTM45 series amplifiers was a GZ34 rectifier tube.

Marshall also made an 18-watt combo amplifier with 2x10" speakers (Model 1958) that looked like a smaller version of the Bluesbreaker, and is sometimes referred to as its "little brother".