Dating fender bassman head
The 5D6 was a major departure from the earlier 5B6 Fender Bassman model.Designed by Freddie Tavares, longtime R&D man at Fender, Instead of the single 15" speaker, four 10" Jensen Alnico P10R speakers were used.
The LTD came equipped with the original 5AR4 rectifier tube, and four Jensen P10R reissue alnico speakers, which was period correct for the original amp.
Initially intended to amplify bass guitars, the 5B6 Bassman was used by musicians for other instrument amplification, including the electric guitar, harmonica, and pedal steel guitars.
Besides being a popular and important amplifier in its own right, the Bassman also became the foundation on which Marshall and other companies built their high-gain tube amplifiers.
The output was 50 watts at 8 ohm into a single 12 inch speaker, with a "Tone Ring" baffle in the speaker cabinet.
In early 1961, model 6G6-A was introduced with a solid state rectifier replacing the GZ34, and two 12 inch speakers with a conventional baffle in a slightly larger cabinet (wired in parallel) with a 4 ohm output.