How old is my vintage amplifier?

There are several ways to determine when a Fender amp was produced. First use the cosmetic features to get a range of possible years. Next, (if applicable) look for the date code on the tube chart. If your amp dosen’t have a date code, flip the amp upside-down and check the transformers, and speakers for their manufacturer codes. If possible, open up the chassis and check a few of the pots’ and capacitors’ manufacturer codes. Remember, many components could have been changed over the years, speakers blow, caps dry out, transformers melt down, and pots wear out.

Here is a cool link to a Vintage Fender Amp price history chart that tracks sales data for specific amp models by the month.

Date Code: Wide panel, narrow panel, brown, blonde, and black face amps have a date code hand-stamped on the tube chart. This code is made up of two letters. The first letter translates to the year and the second to the month. The reissue amps also made use of this code. 

Example: FG=July 1956, QA=January 1967, and a reissue CG=July 1992

Additional Information: 

Expanded Manufacturer Code Chart

EIA Source-Date Codes: Electronic components such as transformers, potentiometers, speakers, and some capacitors are often stampted with a date code indicating who manufactured them and when. The code follows the format: XXXYY ZZ where:
XXX = a two or three (possibly four on newer amps) digit number indicating the manufacturer. (see chart below)
YY = is a one or two digit code indicating the year. If it’s a one digit year you need to determine the correct decade of the amp some other way.
ZZ = a number from 1 – 52 indicating the week of the year.
Remember, your amp is newer than the newest component. So if you find pots from late 68 and transformers from early 69 you can be pretty sure your amp is a 1969.
Date Codes
Letter Code Vintage Year Reissue Year Month
A - 1990 January
B - 1991 February
C 1953 1992 March
D 1954 1993 April
E 1955 1994 May
F 1956 1995 June
G 1957 1996 July
H 1958 1997 August
I 1959 1998 September
J 1960 1999 October
K 1961 - November
L 1962 - December
M 1963 - -
N 1964 - -
O 1965 - -
P 1966 - -
Q 1967 - -
Common Fender Source Codes
Code Manufacturer Part(s)
67 Eminence Speakers
73 J.B. Lansing (JBL) Speakers
137 CTS Potentiometers, Speakers
220 Jensen Speakers
235 Mallory Capacitors
285 Rola Speakers
304 Stackpole Potentiometers
328 Utah Speakers
391 Altec-Lansing Speakers
433 Cleveland Speakers
465 Oxford Speakers
606 Schumacher Transformers, Chokes
649 Electro Voice (EV) Speakers
830 Triad Transformers, Chokes
1098 Pyle Speakers

Serial Number: There is no information readily available for dating Fender amps by serial number but there are people working on it. Check out this Google search for more resources.

Circuit Code: In 1963 Fender stoped using model numbers to identify schematics and began using the model name and an assigned circuit number. These circuit numbers which are located on the tube chart can be usefull for getting a rough date on an amp. Fender often used the same circuit for many years so this is not a very accurate method for amp dating. The code is simple, the first two letters are the revision, where AA is the first revision, AB is the second, etc. The next one or two numbers are the month where January is 1 and December is 12. The last two numbers are the year.
Example: AB763 = second revision, July, 1963
AA1070 = First revision, October, 1970

Misc Dating Info:

Silver face amps with the aluminum trimmed grilles are from 67 or 69.

The fist Master volume controls were first installed in 72.

The raised “Fender” grille logo lost its tail around 76. There are exceptions to this rule like the the Bronco.

Fender installed casters on some larger amps and cabs beginning in 72.