Authorised Marshall Amplification Retailer
How to Date a Marshall Amplifier – A Complete Guide
Dating a Marshall amplifier can be an exciting part of owning one, especially for vintage models with decades of history. Whether you’ve picked up a Silver Jubilee combo, a Plexi head, or a JCM800, knowing its exact year (and sometimes month) can help with valuation, authenticity, and appreciation of its heritage.
Below is a step-by-step guide to identifying the age of your Marshall amp.
1. Check the Serial Number
The easiest starting point is the serial number, usually found on the rear panel of the chassis or on the backplate of combo amps. Marshall serial numbers follow different formats depending on the era:
1960s – Early 1990s
- Marshall used a letter-coded system to indicate the year of manufacture.
- Example: 12345N — the letter "N" represents the year (in this case, 1981).
- Common letter codes:
- A = July 1969 - December 1970
- C = 1971
- D = 1972
- …
- N = 1981
The prefix to the serial number refers to the model, below explains what these mean:
SL/A - 100w Super Lead
SL/B - 100w Super Bass
S/A - 50w Lead
ST/A - 100w Tremelo
T/A - 50w Tremelo
SP/ - Super PA
A/ - 200w
RI - Reissue
Mid-1990s Onward
- Marshall began using longer numeric serials, sometimes including the year directly (e.g., M-2001-45-1234 = 2001 model).
2. Look for a Date Stamp on the Chassis
Many Marshalls, especially older ones, have an ink-stamped date inside the chassis. You may need to carefully remove the back panel or chassis to see it (take proper safety precautions — tube amps store dangerous voltages).
3. Speaker Date Codes
If your amp still has its original speakers, the Celestion date code can be a great clue:
- Celestion used a combination of letters and numbers to indicate day, month, and year of manufacture.
- Example: T1221 G12M 25 with code 19LL = 19th of December 1972.
4. Potentiometer (Pot) Codes
The small metal pots on the control panel often have manufacturer codes (e.g., CTS or ALPHA) that include a date in the format:
137 7345 → 137 = CTS, 73 = 1973, 45 = 45th week of the year.
5. Cosmetics & Features
Certain visual details can also help date your Marshall:
- Logos – Script logos (1962–1965), block logos (1965–mid-’70s), later gold logo styles.
- Tolex – Pinstripe cloth, basketweave, or check grille cloth point to specific eras.
- Control Panels – Plexiglass panels (1965–1969), brushed aluminum, or gold metal panels in later years.
6. Cross-Reference with Marshall Catalogs & Resources
Once you’ve gathered all the above info, compare it with known Marshall production timelines, catalogs, and vintage amp reference books. Many dedicated Marshall forums and enthusiast sites have year-by-year breakdowns.
Final Tips
- Always verify using multiple dating clues — serial numbers alone can sometimes be misleading due to replacement parts or chassis swaps.
- Be careful when opening an amp — if unsure, have a tech check for internal date stamps.
- Knowing the correct year can significantly increase the value of a vintage Marshall, especially limited editions like the Silver Jubilee or early Plexis.
