Serial number plates and stamps

Some makers publish serial ranges that give a year, some number their amps without any chronology, and several have no amp serial system at all. The plate tells you which case you are in.

Marshall, Peavey, Hiwatt, Traynor, Kustom, Orange and Ampeg have published or documented serial systems for parts of their history, and those systems are the fastest route to a year.

Fender, Vox, Gibson, Sunn, Silvertone, Standel, Premier and Magnatone have no factory range for the vintage years. Fender kept no amp archive before 1994, Marshall has nothing standard from 1965 to June 1969, and Vox never published a JMI table.

Even where ranges exist they give a period rather than a day. Chassis were not always used in numerical order, which is one reason a serial number dates an amp to a block instead of a date.

Where a plate exists, read it with the era: the same letters and digits mean different things in different decades, in Marshall and Ampeg alike.

How to read it

01 / Find the serial

On the chassis, the rear plate or the head shell, depending on the maker.

02 / Identify the format

Count the digits, note any letters and their position, and check whether a prefix or suffix carries information.

03 / Match it to the maker

Apply that maker's own system, and do not borrow another maker's table.

04 / Read it as a range

Treat the result as a period, then narrow it with component codes.

05 / Report honestly when nothing matches

A number outside the published ranges, or from a no-data era, is not a date, and saying so is part of the product.

Traps

Chassis numbers were not always used chronologically, so one number can cover a band of years.
The same letter can mean different years under different owners, as Ampeg's letter tables show.
A serial from a no-data era does not become datable by looking harder.

Tables in the archive

Marshall — Model code (series / power)

1965 to today · 14 rows · confidence High · Amp Archives — Marshall serial numbers

Code as marked	Meaning	Source
/A	1965–1969 · 200 W	Blue Book of Guitar Values — marshall
A/	1969–1983 · 200 W	Amp Archives — Marshall serial numbers
S/	1965–1969 · 50 W	Blue Book of Guitar Values — marshall
S/A	1969–1983 · 50 W	Amp Archives — Marshall serial numbers
SL/	1965–1969 · 100 W Super Lead	Blue Book of Guitar Values — marshall
SL/A	1969–1983 · 100 W Super Lead	Amp Archives — Marshall serial numbers
SB/	1965–1969 · 100 W Super Bass	Blue Book of Guitar Values — marshall
SB/A	1969–1983 · 100 W Super Bass	Amp Archives — Marshall serial numbers
SP/	1965–1983 · Super PA	Amp Archives — Marshall serial numbers
ST/	1965–1969 · 100 W Tremolo	Blue Book of Guitar Values — marshall
ST/A	1969–1983 · 100 W Tremolo	Amp Archives — Marshall serial numbers
T/	1965–1969 · 50 W Tremolo	Blue Book of Guitar Values — marshall
T/A	1969–1983 · 50 W Tremolo	Amp Archives — Marshall serial numbers
RI	1969–1992 · Reissue	Amp Archives — Marshall serial numbers

Marshall — Model code + number + year letter (letter at the end)

July 1969 – 1983 · 14 rows

To	Years	Source
99999	1969–1970	Amp Archives — Marshall serial numbers
99999	1971	Amp Archives — Marshall serial numbers
99999	1972	Amp Archives — Marshall serial numbers
99999	1973	Amp Archives — Marshall serial numbers
99999	1974	Amp Archives — Marshall serial numbers
99999	1975	Amp Archives — Marshall serial numbers
99999	1976	Amp Archives — Marshall serial numbers
99999	1977	Amp Archives — Marshall serial numbers
99999	1978	Amp Archives — Marshall serial numbers
99999	1979	Amp Archives — Marshall serial numbers
99999	1980	Amp Archives — Marshall serial numbers
99999	1981	Amp Archives — Marshall serial numbers
99999	1982	Amp Archives — Marshall serial numbers
99999	1983	Amp Archives — Marshall serial numbers

Ampeg — YMMNNN — year digit, month, number

1953 – mid 1965 · 10 rows

From	To	Years	Source
301001	312999	1953–1963	Ampeg — official knowledge base
401001	412999	1954–1964	Ampeg — official knowledge base
501001	512999	1955–1965	Ampeg — official knowledge base
601001	612999	1956	Ampeg — official knowledge base
701001	712999	1957	Ampeg — official knowledge base
801001	812999	1958	Ampeg — official knowledge base
901001	912999	1959	Ampeg — official knowledge base
1001	12999	1960	Ampeg — official knowledge base
101001	112999	1961	Ampeg — official knowledge base
201001	212999	1962	Ampeg — official knowledge base

Fender — Universal A6/A7/A8/A9/B/F9/F0–F4 (silverface 1975–1984)

· 11 rows

Prefix	From	To	Years	Source
A6	A600000	A699999	1976–1977	ggjaguar — Fender amp research (Gagliano series) — Part 6
A7	A700000	A799999	1977–1978	ggjaguar — Fender amp research (Gagliano series) — Part 6
A8	A800000	A899999	1978–1979	ggjaguar — Fender amp research (Gagliano series) — Part 6
A9	A900000	A999999	1979–1980	ggjaguar — Fender amp research (Gagliano series) — Part 6
B	B00000	B99999	1975–1976	ggjaguar — Fender amp research (Gagliano series) — Part 6
F9	F900000	F999999	1979–1980	ggjaguar — Fender amp research (Gagliano series) — Part 6
F0	F000000	F099999	1980–1981	ggjaguar — Fender amp research (Gagliano series) — Part 6
F1	F100000	F199999	1981–1982	ggjaguar — Fender amp research (Gagliano series) — Part 6
F2	F200000	F299999	1982–1983	ggjaguar — Fender amp research (Gagliano series) — Part 6
F3	F300000	F399999	1983–1984	ggjaguar — Fender amp research (Gagliano series) — Part 6
F4	F400000	F499999	1984	ggjaguar — Fender amp research (Gagliano series) — Part 6

Hiwatt — Serial plate identification (which era / which maker)

1966-present · 7 rows · confidence High · hiwatt.org — Hiwatt dates & history

Check the plate text BEFORE applying the range table: Turntone/Sterling numbers fall inside the vintage ranges even though those amps are from 1985 or later.

Code as marked	Meaning	Source
HYLIGHT ELECTRONICS (HIWATT AMPLIFICATION) LIMITED	1966–1981 — plate on the metal chassis	hiwatt.org — Hiwatt dates & history
HIWATT BIACROWN LTD.	1981–1984 — plate on the metal chassis (late 1981 start)	hiwatt.org — Hiwatt dates & history
Sterling Imports plate	1984–1985 — made at Sterling Imports' Modesto, California facility in late 1984 or 1985; 'these serial numbers were not consistent'	hiwatt.org — Hiwatt dates & history
Turntone 'L' series, no maker name	1985 onwards — plate says only 'Made in England'; serials often fall inside the vintage ranges	hiwatt.org — Hiwatt dates & history
AB prefix	1990–1999 — Audio Brothers, England, made in the 1990s	hiwatt.org — Hiwatt dates & history
single letter + HIWATT UK / LONDON / DONCASTER	2000 onwards — Music Ground, the current manufacturers, from the early 2000s	hiwatt.org — Hiwatt dates & history
cut-down plate	speaker cabinet plates were sometimes 'cut down' and used when the stock of normal plates ran out — a cut plate may indicate a cabinet rather than an amp	hiwatt.org — Hiwatt dates & history

Gretsch (amps) — Metal plate vs foil sticker (which numbering system applies)

1941-1968 · 0 rows · confidence Medium · Gretsch forum — dating Gretsch & Valco amps

All numbers are approximate matches; the plate type must be checked before decoding.

Supro / Valco — Which plate you are looking at (metal plate vs foil sticker)

1940-1968 · 0 rows · confidence Medium · Gretsch forum — dating Gretsch & Valco amps

Physical identification of which system applies. Foil stickers peel off and were often lost, in which case the amp is undateable without component codes.

Frequently asked

Which makers can give a year from the serial?

Marshall from July 1969, Peavey by formula, Hiwatt for 1966–84, Traynor in the 1960s and 1970s, Kustom 1965–80, Orange 1968–79 and Ampeg in most eras.

Why do I get a range instead of a year?

Because the tables are built from documented production blocks, and chassis numbers were not always used in chronological order.

What if my serial is in no table?

Then the amp belongs to a no-data era or to a maker without a serial system, and component codes, era features and cosmetics are the honest substitutes.

Open a maker and enter your code →