Marshall cabinet serial number dating
The table below outlines the meaning of these letter codes.
Marshall amplifiers didn’t start using true serial numbers until July of 1969.
Note: "A" Date Code: The "A" Date Code ran for 18 months (July 1969 - December 1970) so the "B" Code was not used.
1979-1981: Some Marshalls made from 1979 to 1981 have the serial number on the front panel.
For example: S/L C 12357 S/L would indicate the model Super Lead 100 watt C indicates the year 1971 12357 is the serial number. Starting in 1993 until 1997 Marshall switched over to a new serial number system.
How to read the serial number (1984-1992) In 1984, the order of the serial number components changed to (a)(c)(b), but the method used to determine the values for (a) and (c) remain the same.
From 1962 until 1964 Marshall amplifiers were identified by a four-digit sequential number inside the back panel, reportedly starting with 1001 in 1962 and reaching 2001 at the beginning of 1964.
Examples: 0009 1963 JTM 45 Offset 1186 1963 JTM 45 Offset 2260 1964 JTM 45 Lead More Examples Beginning in 1965 Marshall abandoned the four-digit numbering system and began using model numbers, sometimes called series numbers and model codes.
Marshall amps began featuring aluminum back panels in 1969.
Serial numbers began appearing on the back panels in July 1969.The switch from 6L6 to the KT66 valve gave Marshall amps a more aggressive tone.