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Marshall amplifier serial numbers made simple


Dating a Marshall amplifier can be a daunting task for even the most savvy of suitors — Amp Archives is here to help.

1962 – 1964

The earliest Marshall amplifiers were made in 1962 and had no model or serial numbers. 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

1965 – 1969

Beginning in 1965 Marshall abandoned the four-digit numbering system and began using model numbers, sometimes called series numbers and model codes. While there are serial-like numbers during this era, no standard serial number format has been identified.

The model numbers can be somewhat confusing because model numbers such as 1987 or 1959 can be mistakenly interpreted as the production year of the amplifier. Amplifiers from this era must be dated within this time span based on their features, or component manufacturers and codes, including speakers, potentiometers and transformers.

1965

  • Back panels are cream colored.
  • JTM-45 block logos changed to gold-plated plastic script, these are fragile and many have been replaced.
  • Cabinet feet are small round and gray.
  • Handles changed to plastic with larger end cap.
  • Power tubes are KT66, 6L6 and 5881.
  • RS Spares or Drake transformer, rated at 8000 ohms, used in the JTM-45.
  • Some JTM-100 amps from late 1965 have the JMT-45 badge.

1966

  • Power tubes are EL34 or 6550.
  • JTM-45 logo changed to JTM-50 and JTM-100 indicating the amp’s wattage.
  • Single 100W Drake transformer, rated at 4000 ohms, part number 784-084, for 100W models.
  • Single 50W Drake output transformers rated at 3,400 ohms, part number 784-139, for 50W models.
  • GZ34 rectifier no longer used.
  • Cabinets have corner-lock joints with a quality control signature inside.

1967

  • Reverse (Black Flag) JTM logo used for half the year, carrying over from late 1966.
  • Gold Plexigas back panel, changed from cream-colored.
  • Dagnall transformers used in the JTM-100, changed from Drake.
  • Chassis construction transitions from aluminum to steel in late 1967.
  • First 200 Watt Majors appeared, with treble, bass and volume controls, active tone circuitry and KT88 tubes.

1968

  • White logo (changed from gold)
  • The lip/shelve under the control panel is curved, changed from straight.
  • Amp model prefix changed from JTM to JMP (Jim Marshall Products).
  • The 200 watt Major was modified to match the normal panel layout and the active electronics where dropped.
  • The output transformer turned 90 degrees in comparison to earlier models to reduce hum.

1969

  • Plexiglas panels changed to brushed aluminum startiong in early 1969.
  • Larger black cabinet feet starting in July 1969, changed from small and gray.

Examples:

1479 1965 JTM 45
5200 1966 JTM 45
SL/ 10584 1967 Model #1959 JMP Super Lead
SP/ 20099 1967 Model #1968 JMP Super PA
SB/ 10257 1967 Model #1992 JMP Super Bass
S/ 10637 1968 JMP
S/A 2148 A 1969 JMP

More Examples

The model number takes the form of four-digits preceded or followed by letter codes describing amplifiers characteristics. The table below outlines the meaning of these letter codes.

Model Code Model Type
S/ or S/A 50 Watt
/A 200 Watt
SL/ 100 Watt Super Lead
SB/ 100 Watt Super Bass
T/ 50 Watt Tremolo
ST/ 100 Watt Tremolo
SP/ Super PA

1969 – 1983

Marshall amplifiers didn’t start using true serial numbers until July of 1969. The full identifier of these amps was initially comprised of a model code, the serial production number and the date code.

Examples:

S/A 4779 G 1975 Model #1987 JMP Lead
S/A 4279 H 1976 Model #1987 JMP Lead
S/A 08840 H 1976 Model #2204 JMP Master Volume

More Examples

Letters were used as date codes to represent the year of production and this letter followed the serial production number. Letters B, I, O and Q were not used to avoid confusing letters with numbers.

Model Code Model Type
S/ or S/A 50 Watt
A/ or /A 200 Watt
SL/ or SL/A 100 Watt Super Lead
SB/ or SB/A 100 Watt Super Bass
T/ or T/A 50 Watt Tremolo
ST/ or ST/A 100 Watt Tremolo
SP/ Super PA
RI/ Reissue
Date Code Year
A 1969-70
C 1971
D 1972
E 1973
F 1974
G 1975
H 1976
J 1977
K 1978
L 1979
M 1980
N 1981
P 1982
R 1983

1984 – 1992

Starting in 1984 the date code letter was moved from the end to the middle of the production code, between the model code and the production number.

Examples:

U 08177 1986 Model #2204S JCM 800 Master Volume Mini-stack Version
S/A V 10779 1987 Model #2204 JCM 800 Master Volume
S/A W 30626 1988 Model #2203 JCM 800 Master Volume
S W 29583 1988 Model #1987S Lead

More Examples

Date Code Year
S 1984
T 1985
U 1986
V 1987
W 1988
X 1989
Y 1990
Z 1991-92

1992 – 1997

In October of 1992 Marshall began using stickers printed with serial numbers and bar codes. These were comprised of nine digits in the format of xx-xxxxx-xx (though not always). These serial numbers can be decoded as follows:

  • The first two numbers indicate the last two digits of the year of production.
  • The middle five numbers indicate the production number.
  • The last two numbers indicate the week of the year 01 being the first week of the year through to 52 being the last week of the year.

Examples:

93-10232-12 1993 Model #9100 Valve Amp for JMP-1
RI 95-94082-45 1995 Model #2245 JTM 45 Reissue
S/A 95-54517-05 1995 Model #2203 JCM 800 Master Volume
RI/ 969096734 1996 Model #1987X Reissue

More Examples

1997 – Present

In August of 1997 Marshall switched to their current serial number format which contains more information and is easily decoded.

Examples:

M-2000-07-1427-Z 2000 Model #1960AX
M-2000-27-1452-Z 2000 VBC810 Bass
M-2002-21-0524-B 2002 Model #2203ZW JCM 800, Zakk Wylde, 524 of 600

More Examples

These are printed on a sticker and affixed to the back of the amplifier and are comprised of a letter followed by ten numbers followed by another letter: A-xxxx-xx-xxxx-A.

  • The first letter indicates what country the amp was manufactured in.
    Code Country
    M England
    C China
    I India
    K Korea
  • The next four digits indicate the year of production.
  • The next two digits indicate the week of the year during which the amp was produced 01 being the first week of the year through to 52 being the last week of the year.
  • The next four digits indicate the production number.
  • The final letter indicates the voltage specification.
    Code Voltage
    A 230 VAC, UK
    B 120/60 VAC, US
    C 220/50 VAC, Canada
    D 105/50/60 VAC, Japan
    E 220/60 VAC, Europe
    F 130/60 VAC, Mexico
    Z Speaker Cab

It’s important to note that, especially in the early years, Marshall was not always consistent — there are exceptions to these rules. Checking against other amps from the era as well as component markings (speakers, potentiometers, transformers) can help to confirm a year of production.

Welcome Dumble Amplifiers to the Amp Archives


Alexander (Howard) Dumble’s boutique amplifiers are the most coveted in the world, often fetching hundreds of thousands of dollars. Every amplifier was hand-built to order and the waiting list could take several years with strict caveats governing customer conduct. Thanks to the studious work of Rob Livesey we’re excited to add over 70 Dumble amplifiers to the Amp Archives.

In 2011 the Dumble Overdrive Special was assessed as the most valuable guitar amplifier on the market, with used amplifiers fetching on average between $70,000 and $150,000 each. With a scant 300 Dumble amps estimated to exist, the myth, the demand and the history of each amplifier continues to grow.

For more history on the unique man behind these iconic amplifiers Steve Rosen has a great article over at Rock Cellar Magazine, Behind the Curtain: Getting Amped with Alexander (Howard) Dumble.

Featured Amp: The Gospel Machine’s matching 1957 Fender Tweed Champ


On National Tweed day we feature a 1957 Fender Tweed Champ with a history founded in American gospel.

The story of the Gospel Machine and it’s matching Fender Champ begins in a little town in Minnesota named Karlstad, where Christian and Ester Pedersen were farmers on a tract of land acquired through the U.S. Homestead act. When the pastor of the Pedersen’s local church decided to broadcast a gospel program on the local KTRF radio station in 1950, the Pedersens and their children took part in the broadcast.

In early 1957 Ester and Christian decided to purchase a new guitar and corresponding amp, and this Tele and Champ traveled all around Minnesota and the adjoining states. Christened the “Gospel Machine” by the Pedersen family, the guitar was passed down from Ester to her daughter Adeline. The guitar and amplifier remained in the family until 2001, at which point they were sold to one of the owners of Mike & Mike’s Guitar Bar where they are now offered up for sale.

The original yellow Astron caps are present in the preamp, the original transformers are intact, and the chassis itself has a nearly flawless chrome faceplate with all of its stock white silkscreen lettering. While the singular CTS pot in the circuit dates to the 46th week of 1956, the mint tube chart has a “GD” date code which translates to April of 1957, and the Oxford 8″ speaker dates to the 15th week of 1957 as well. The Gospel Machine’s matching Tweed Champ is now included in the Amp Archives here.

The Fender Champ evolved out of the Champion 600 and 800 which launched in the late 1940’s. Originally, the Champ was a tweed-covered 4 watt amp with a 6-inch speaker, characteristics which are perfectly exemplified in this fantastic piece of musical Americana.

Photos and history courtesy of Mike & Mike’s Guitar Bar, Seattle, Washington.


Have an amplifier with a story?

If you have an amplifier with an interesting story and would like it added to and featured on Amp Archives please send us the details using our contact page.

Featured Amp: Kim Sherman’s Fender Champion 600


This 1950’s Fender Champion belonged to the late Kim Sherman, lead guitarist for the Frantics. The Frantics were formed in 1965 and drew their influences from Jeff Beck, Jimmy Page, and, later, Jim Morrison.

According to Kim’s brother, Kit Sherman, Kim owned a whole set of Fenders, a Bassman, a Champion, 2 Champion 600’s and a Tweed. Pictured above, below and now included in the Amp Archives is one of Kim’s 1950’s Fender Champion 600’s. This Fender Champion 600, dating to between 1951 and 1952 is currently for sale*, along with some other pieces from Kim’s collection. *The auction for this amplifier has ended

First introduced in 1948, the Champion sported the name Champion 800 (with 8″ speaker), changing a year later to Champion 600 (6″ speaker) with circuit designation 5B1. It was rated at about 3 watts, featuring a “T.V. Front” style cabinet; the 800 was covered in greenish fabric while the 600 featured two-tone blonde and brown vinyl covering.

Aside from the Frantics, some of whose tunes you can find on YouTube, Kim also played with the Malibus, It & The Things and the Mag Rims. Before passing away in his home in Hawaii in 2013 Kim had become a well loved part of Montana’s musical history.

Kim and other members of the Frantics are pictured above with members of the Yardbirds. From left to right, Chris Dreja, Don Mock, Jack Mills, Gary Eidet, Jimmy Page, Max Byfuglin and Kim Sherman. Photo Credit Dave Martens, Fairgrounds, Great Falls, Montana Aug. 14, 1966.

An early promo poster for the Frantics from Billings, Montana, Kim Sherman pictured 2nd from the right. For more of the Frantic’s history head on over to Lost Sounds Montana.


Have an amplifier with a story?

If you have an amplifier with an interesting story and would like it added to and featured on Amp Archives please send us the details using our contact page.

Demystify the Plexi era with 425 new examples


Thanks go out to Tazin for providing Amp Archives with over 3,000 photos relating to 425 Marshall Plexi era amplifiers, each complete with model, year, serial number and more. These resources are now available for browsing and searching in the Amp Archives.

Between the years of 1965 and 1969 Marshall often used Plexiglas panels for amplifier front and back faceplates. These Plexiglas panels led to the name “Plexi”, and while 50 watt models of the time are also called Plexis, the 1959 100 watt model is generally thought of as the “definitive” Plexi.