How To Date Your Speaker
All Celestion date codes contain a pair of letters. These represent the month and year of manufacture.
A number directly next to the pair of letters, if present, is the day of the month.
To date your speaker, simply use the reference table below to decipher the pair of letters.
In the example above, GB17 = 17th July 1969. The additional letter ‘Y’ can be ignored.
Date Stamp Locations
For 12″ speakers, the location of the date stamp can guide us to the right time period. These are colour coded on the chart below.
The date stamp location for 15″ and 18″ speakers, tends to be on the outer rim of the chassis.
Celestion Date Codes Chart
|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||G - 2021ah|
|H - Aug||H - 1951||H - 1963||I/J - 1976||H - 1998a||H - 2022ah|
|I/J - Sep||I/J - 1952||I/J - 1964||K - 1977||I/J - 1999a||I/J - 2023ah|
|K - Oct||K - 1953||K - 1965||L - 1978||K - 2000a|
|L - Nov||L - 1954||L - 1966||M - 1979||L - 2001**ah|
|M - Dec||M - 1955||M - 1967||N - 1980||M - 2002ah|
|A - 1968*||P - 1981||N - 2003ah|
|Stamp locations:||Q - 1982||P - 2004ah|
|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 & some UK made greenbacks||Y - 1990||X - 2012ah|
|Z - 1991||Y - 2013ah|
|*Transition from front gasket to chassis leg = April 1968||Z - 2014ah|
|**Transition from chassis leg to magnet sticker = early 2001|
Note – Ceramic guitar speakers (greenbacks) first appeared around 1964 / 1965, so it is highly unlikely you will find any earlier than this. Before 1965 guitarists were mainly using the alnico G12 models.
’23KH’ on the chassis rim, would be 23rd October 1951
’15BH’ on the front gasket, would be 15th February 1963
‘DC18 N’ on the chassis leg, would be 18th April 1970. Ignore the additional inspection letter.
‘HE V’ on the chassis leg, would be August 1972. Ignore the additional inspection letter.
’10HG’ on the chassis leg, would be 10th August 1997
’27CS’ on a magnet sticker, would be 27th March 2007
Please also use the example photos at the bottom of the page for comparison. These can be very helpful 😉
About The ‘Stamp Format’
You might have read on other websites and books to use the stamp format to date Celestion speakers.
Generally speaking, there was an alternating cycle of Day-Month-Year (DDMY) then Month-Year-Day (MYDD). These are included at the top of the chart for reference and can be helpful for guidance.
However, just be careful using this method. There are quite a few speakers out there that do not comply, and this tends to confuse people.
Oddities and typos
1) Sometimes the month and year codes were printed back to front by mistake. eg HA16 instead of AH16 for 16th Jan 1975.
A particular hotspot for this typo is late 1974 into early 1975. The way to spot them is by looking at the other period features of the speaker. For example, the cream coloured magnet covers tend to be from 74 or 75, rather than 1968.
I have written a more in-depth article on how to identify these typos here – back to front celestion date codes.
2) Through mid 1968 you might find the codes printed on the outer rim of the chassis instead of on the chassis leg.
3) Some speakers, such as the sidewinder series, may have their date stamps printed on the outer edge of the ceramic magnet instead of the chassis leg. Probably because the frame leg is painted black.
An extra single letter is apparently just an ‘inspection letter’ and can be ignored. For dating purposes it is useful to know these are only usually present on speakers made between 1969 to 1976. From 1986 onwards a two digit number is normally 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. It is an important stamp to look for when authenticating old ‘pre-rola’ speakers.
Example Celestion date codes through the years
1944 to 1951
Date codes are usually printed on the outer rim of the chassis and consist of 4 digits only.
1952 to Spring 1966
Date codes 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. The date code is still on the front gasket but with a smaller font size.
Fake Celestion date codes
Any greenback speakers with pre-April 1968 date codes 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 codes 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.
1969 to mid 1976
Date codes are printed vertically on the frame. An additional inspection letter is usually included (except Aug 73 to Jun 74), these can be ignored for dating purposes.
Leading zeros are usually omitted from the day of the month, eg ‘6’ instead of ’06’.
From around Dec 1971 to Sept 1972 the day of the month is usually omitted:
mid 1976 to late 1985
From around June 1976 the inspection letter is no longer included.
The circular quality control stamp changes appearance through the years: From roughly March 1978 to mid 1980 – usually a large letter ‘P’ or ‘Q’. From around mid 1980 to late 1985 – usually an “insp number” stamp with no circular border.
From about mid 1983 to 1986 the T model number is rarely stamped on the frame leg because it is shown on the speaker label.
1986 to late 1987
From around Jan 1986 onwards the ‘insp’ stamp is no longer used and the two digit inspection number is appended to the end of the date code instead. These inspection numbers can be ignored for dating purposes.
Late 1987 to early 1990
From around Dec 1987 to April 1990 – the date code, speaker model, and inspection number are joined together in one continuous line. The letter ‘T’ prefix is usually omitted from the speaker model.
1990 to mid 2001, & ‘Heritage’ models, & UK made greenbacks 2001 to 2005
From around April 1990, the ‘T’ prefix is usually included with the model number.
From 1991 onwards, leading zeros are usually included with the day of the month, eg ’08’ instead of ‘8’.
Alnico models – 1994 to present day
Date codes are printed on the front gasket and may include the model number and inspection number.
Standard production models – early 2001 to present
Date codes are printed on a magnet sticker and go back to the simple 4 digit system.