Fender recommends dating unstamped amps by the EIA number on the transformers.The format is always EIA 606-Y-XX or 606-YY-XX where Y indicates the year (196Y/197Y or 19YY respectively) and XX the week. Dating by serial number, while less accurate, can be of some use.The brownface amps originally featured a dark maroon or "oxblood" grillcloth, which was changed to "wheat" in 1962-63.The Brown amplifiers included all of the all-in-one combo amps except the flagship Twin and Vibrasonic, and the little Champ which retained its "tweed" (twill) covering.Toward the end, despite keeping such construction, Fender utilized tolex to cover its amps.The Brownface series was introduced in 1959 and discontinued in 1963.There were many notable accomplishments for the company's amplifier division during these years.
The first letter indicates the year: M 1963 N 1964 O 1965 P 1966 Q 1967 R 1968 S 1989 The Second Letter indicates the month: A January B February C March D April E May F June G July H August I October J September K November L December Check the EIA number.
Stamped on the metal backing of most amps is the serial and production number. The following list, compiled by Greg Gagliano, establishes dates through 1976: A00100 to A01200 - 1964 A01200 to A04300 - 1965 A04300 to A07000 - 1966 A07000 to A10400 - 1967 A10500 to A11300 - 1967 A10500 to A16500 - 1968 A16500 to A21400 - 1969 A21400 to A25600 - 1970 A25600 to A37000 - 1971 A37000 to A50500 - 1972 A50500 to A68000 - 1973 A68000 to A99999 - 1974 A81000 to A99999 - 1975 B01000 to B15000 - 1975 B15000 to B68000 - 1976 If these steps are unsuccessful, a number of books have been published that help to date amps based on part codes.
Leo Fender began building guitar amps before he started manufacturing guitars.
This period marked the beginning of Fender's use of Tolex to cover amp cabinets.
The name 'brownface' stems from the brown-colored control panels, common to both the brown- and cream/blonde- Tolex-covered amps.