If the label reads "Fender Electric Instruments," it was built before 1965.If it reads "Fender Electric Instruments" it was built sometime after Fender was sold to CBS, which was in 1965. Twin Reverb amps made between the years of 19 had aluminum trim surrounding the sparkling blue grillcloth on the front of the amp.
From 1982 to 1986, the name was the Twin Reverb II and the power was changed to 105 watts.
The black nameplate was also brought back on these models. In 1987, The Twin Reverb II was replaced by The Twin, which featured red knobs, a separate gain channel and a switchable overdrive.
Neither the date nor the value can be determined from the serial number.
Fender’s amps, unlike their guitars, are not tracked by the serial number.
Guitarists worldwide revere the legendary Fender Twin Reverb for its brilliant clean tones and luscious spring reverb.
Although Fender never kept serial number records of its amps, you can determine the approximate year your Twin Reverb was built by matching it against the cosmetic changes the amp has gone through.
Dating Fender Amps 1951-1967 – Tube chart on the inside of the amp is stamped with two letters (A – Q): The first letter designates the year and the second letter designates the month.
A 1951 JAN B 1952 FEB C 1953 MAR D 1954 APR E 1955 MAY F 1956 JUN G 1957 JUL H 1958 AUG I 1959 SEP J 1960 OCT K 1961 NOV L 1962 DEC M 1963 N 1964 O 1965 P 1966 Q 1967 Mid ’70s – early ’80s – Amplifiers are dated much the same way as Fender guitars from the same era: B 5 digits 1975 – 1976 A6 5 digits 1976 A7 5 digits 1977 A8 5 digits 1978 A9 5 digits 1979 F0 5 digits 1980 F1 5 digits 1981 F2 5 digits 1982 – 1983 F3 5 digits 1983 – 1984 F4 5 digits 1984 – 1985 F9 5 digits 1979 – 1980 Dating Contemporary Fender Amplifiers All Fender amplifiers manufactured from 1990 – present include a date code printed on the quality assurance (QA) sticker on the back of the amp chassis, and are dated the by the first letter as the year and the second letter as the month.
The so-called "Red Knob Twins" were made until 1994.