|MONTH||1944 - 1955|
|1956 - 1968|
|1969 - 1991|
|1991 - 2014|
|2015 - 2020
|A - Jan||A - 1944||A - 1956||B - 1969||A - 1991||A - 2015ah|
|B - Feb||B - 1945||B - 1957||C - 1970||B - 1992||B - 2016ah|
|C - Mar||C - 1946||C - 1958||D - 1971||C - 1993||C - 2017ah|
|D - Apr||D - 1947||D - 1959||E - 1972||D - 1994a||D - 2018ah|
|E - May||E - 1948||E - 1960||F - 1973||E - 1995a||E - 2019ah|
|F - Jun||F - 1949||F - 1961||G - 1974||F - 1996a||F - 2020ah|
|G - Jul||G - 1950||G - 1962||H - 1975||G - 1997a|
|H - Aug||H - 1951||H - 1963||I/J - 1976||H - 1998a|
|I/J - Sep||I/J - 1952||I/J - 1964||K - 1977||I/J - 1999a|
|K - Oct||K - 1953||K - 1965||L - 1978||K - 2000a|
|L - Nov||L - 1954||L - 1966||M - 1979||L - 2001a|
|M - Dec||M - 1955||M - 1967||N - 1980||M - 2002a|
|A - 1968*||P - 1981||N - 2003a|
|Stamp locations:||Q - 1982||P - 2004a|
|Green = chassis rim||R - 1983||Q - 2005ah|
|Yellow = front gasket||S - 1984||R - 2006ah|
|Blue = chassis leg||T - 1985||S - 2007ah|
|Purple = magnet sticker||U - 1986||T - 2008ah|
|V - 1987||U - 2009ah|
|Speaker models:||W - 1988||V - 2010ah|
|a = Modern alnico models||X - 1989||W - 2011ah|
|h = Heritage models||Y - 1990||X - 2012ah|
|Z - 1991||Y - 2013ah|
|*Transition from front gasket to chassis = April 1968||Z - 2014ah|
How To Date Your Speaker
Step 1 – Check The Stamp Location
The location of the date stamp tells us the most likely date range the speaker was made:
- On the chassis rim = 1944 to 1951 (or printed there by mistake – see grey text below)
- On the front gasket = 1952 to March 1968 (& modern alnicos 1994 to present)
- On the chassis leg = April 1968 to 1999 (& heritage series 2005 to present)
- On a magnet sticker = 2000 to present
**On rare occasions chassis leg period date stamps were printed on the chassis rim by mistake, these are most common through mid 1968.
Step 2 – Decipher The Date Code
All Celestion date codes contain a pair of letters representing the month and year the speaker was made. In most cases the first letter represents the month, and the second letter represents the year.
To date your speaker, simply find the pair of letters in your date code and use the chart at the top of the page to decipher them. Use the stamp location colour codes to guide you.
Note: Be careful of date stamps printed in reverse (year then month). These are generally rare but are fairly common on mid 1970’s creambacks.
A number directly next to the pair of letters, if present, is the day of the month. So ‘GB17’ on the photo above = 17th July 1969 (ignore the ‘Y’).
It’s that simple!
More example date stamps are shown further down the page.
What About The Stamp Format?
You might have read on older websites to use the stamp format to date your speakers.
Although the stamp formats can be useful for verification, I do not recommend using them as the main basis for dating your speakers. The truth is, a lot of date stamps do not correspond with those formats and this confuses a lot of people.
An extra single letter is apparently just an ‘inspection letter’ and can be ignored. However, for dating purposes – they are only usually present on speakers made between 1969 to 1976. From 1986 onwards a two digit number is used instead.
The code beginning with the letter ‘T’ is the model number of the speaker. For example ‘T1281’ represents a 55Hz 16 Ohm G12H.
The small circular stamp with ‘insp’ text or a letter ‘P’ inside it, is a quality control stamp. This is an important stamp to look for to authenticate old ‘pre-rola’ speakers.
Example date codes through the years
1944 to 1951
Date stamps are usually printed on the outer rim of the chassis and consist of 4 digits only.
Note: You might read elsewhere that the month codes changed in 1963. This is incorrect – they always went from A to M, skipping the letter ‘I’. If you do ever find a letter ‘I’ in a Celestion date code it is just a typo and should be a letter ‘J’.
1952 to Spring 1966
Date stamps are usually stamped on the front gasket of the speaker. Notice the large font size and white manilla paper gasket. A leading zero is used for single digit numbers.
The font size is reduced from around mid 1965 onwards.
Spring 1966 to March 1968
The gasket material is made from cork with a thin paper overlay and is made up of 4 separate pieces. Date stamp is still on the front gasket but with a smaller font size.
Fake date stamps
Any greenback speakers with pre-April 1968 date stamps printed on the chassis leg are likely to be fakes. Genuine stamps would be on the front gasket (as in the previous photo above) until April 1968.
April 1968 to December 1968
Date stamps are printed horizontally on the frame. The faint ink can sometimes make them difficult to read. Occasionally they might be printed on the outer rim.
Note: The typical stamp format for 1968 is DDMY, not MYDD as stated on other websites.
1969 to 1985
Date stamps are printed vertically on the frame, and leading zeros are usually omitted from the day of the month.
From Jan 69 to Aug 73, and from Sep 74 to Sep 76, an additional inspection letter is usually included. These can be ignored for dating purposes.
Dec 1971 to Sep 1972
From Dec 71 to Sep 72 the day of the month was omitted.
From 1986 onwards a two digit inspection number is usually included. These can be ignored for dating purposes.
1987 to 1991
From around 1987 onwards the date stamp, speaker model, and inspection number are joined together in one continuous line. The letter ‘T’ prefix is sometimes omitted from the speaker model.
Standard models – 1991 to 2000, and all ‘Heritage’ models
Date stamps are printed on the leg of the chassis.
Alnico models – 1994 to present day
Date stamps are printed on the front gasket and may include the model number and inspection number.
Standard production models – 2000 to present
Date stamps are printed on a magnet sticker and go back to the simple 4 digit system.