Dating fender amps chassis number
They were made in three sizes, 1×8" (one 8-inch speaker), 1×10", and 1×15".
They are all very rare today and few have survived.
While the majority of the piggybacks were produced in blonde tolex, there are a few examples of the brown tolex Bassman amplifiers.
Accomplishments for the company's amplifier division during these years include the introduction of the stand-alone spring reverb unit in 1961, followed by incorporation of the reverb circuit within a combo-amp design with the 1963 Vibroverb.
The first of these were the K&F models, produced between 19.
These early models are referred to as "TV-Fronts" due to the shape of the cabinet when viewed from above.
The Dual Pro was the first twin-speaker amplifier, and also the first to employ a finger-jointed pine cabinet and the amp with a top-facing control panel.
The name 'brownface' stems from the brown-colored control panels, common to both the brown- and cream/blonde- Tolex-covered amps.
The brownface amps originally featured a dark maroon or "oxblood" grillcloth, which was changed to "wheat" in 1962-63.
The first cloth used was an off-white fabric, followed by a horizontal-stripe two-tone pattern, and finally a two-tone twill.