Other sources to date your amp may include serial numbers and overall look and visual components on the amp as well.
From July of 1969 until September of 1992 the date code system included a letter of the alphabet in the serial number.
Here are the letters with their corresponding years.
July 1969 - December 1983 EXAMPLE: SL/A 24523 D SL/A = Model Code 24523 = Serial Number E = Date Code This amp would have be a 100 Watt Super Lead 1972 January 1984 - October 1992 EXAMPLE: S/A T 24523 S/A = Model Code T = Date Code 24523 = Serial Number This ampwould have be a 50 Watt 1985 JCM900's The JCM900's began using a Bar Code system which consists of 9 digits which are broken down into three sections.
EXAMPLE: 950322589 95 = Year 03 = Month 22589 = 5 digit serial number This amp would have been made in March 1995.
Post a link of the desired amp on the “Ebay Watch Post”, so we can help analyzing it. I’ll concentrate on “how they sound”, “how they look like” and also “how to tell them apart”. It was made as a head and as a combo (known as the “Bluesbreaker” combo).
In this article, I’ll try to cover the more “desirable” Marshall amps that were built since 1962 up to the JCM800 series, wich most consider to be the “last” great Marshalls produced (That until Marshall released the Vintage Modern series. I will also try to give examples of where they were used.. I hope you like it These are just a few of the thousands of codes that Marshall came up with for their amps. There were many cosmetic changes on the first years until it finally got the “Classic Marshall Look” by 1964.
This (a)(b)(c) sequence began in 1969 and was valid through 1983.
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.
Dating an amplifier by serial numbers can be effective as well.
Again, it's important to be sure the parts are original on the music equipment to get a valid date for the amp.
Many tube amplifiers will have a tube chart within the amp itself.