Celestion occasionally printed their date codes with the month and year back to front by mistake. A simple typo but it can be very misleading.
Year by year Celestion made small changes to their speakers, so an easy way to verify the date code is just to look at the visible features of the speaker. The most obvious ones being:
- The colour of the magnet cover
- The cone stamp
- The location and general appearance of the date stamp
- The label
If you can familiarise yourself with the transition periods for these details you will find it a lot easier to date your speakers accurately. My blog post ‘How To Date Celestion Greenbacks‘ has all the information you need, and I’ll be referring to it throughout this post.
Here are a few examples:
Celestion were mainly only using the cream coloured magnet covers from spring 1974 to mid 1975. So this is a really easy way to date your speakers.
The date code ‘GM4’ on this speaker might appear to be July 1967 or July 1979. However, the general appearance of the speaker tells us it is a mid 1970’s speaker, and therefore we know the date code is back to front and should be ‘MG4’ – 4th Dec 1974.
Some of the visible features that indicate this are:
- The cream magnet cover – found spring 1974 to mid 1975
- The 0444 cone stamp – found late 1974 to mid 1975
- The inspection letter (‘X’ on this speaker) – found 1969 to 1976
…and there are a few more smaller details that I won’t bore you with.
We can also consider the features of the other contenders. A speaker from July 1967 would be a 20w pre-rola greenback with the date code printed on the front gasket. A speaker from July 1979 would be a ‘blackback’ with no inspection character in the date code and a 444 stamped Kurt Mueller cone. All very different looking speakers.
This stuff might sound complicated but it really isn’t, once you become a bit more familiar with the little changes Celestion made through the years.
Thankfully, most pre-rola speakers do not have back to front date stamps, however watch out for them around late 69. This does seem to be a bit of a hotspot for them.
The date code ‘BK’ here represents Oct 1969. Not Feb 1965 or Feb 1977.
We know the speaker is from 1969 just by the general appearance of it. Here are a few of the main indicators:
- Green magnet cover – typical from 1966 to 1973
- The 25w 16 Ohm G12M pre-rola label – typical from late 1968 to spring 1971
- The 102 003 pulsonic cone stamp – typical from 1968 to spring 1971
- The added inspection letter – typical from 1969 to 1976
Feb 1965 is before the T1221 was even being made to my knowledge.
Feb 1977 would be a very different looking speaker – a ‘blackback’ with a Rola Ipswich label, and a ‘1777’ stamped Kurt Mueller cone.
1972 vs 1973
Speakers made in 1972 with date codes seemingly from 1973 are fairly common. Granted it is not the end of the world if you are only out by one year, but lets have a closer look:
This speaker was made June 1972, not May 1973, and should be printed ‘FE’, not ‘EF’. How do we know that?
- 102 3 cone stamp – typical from April 1971 to around Feb 1973
- The day of the month omitted from the date code – typical from Dec 71 through to Sept 72
- Smooth paint finish to the chassis – typical until Oct 1972
For direct comparison here is a typical greenback speaker from mid 1973. Spot the difference.
- ‘3’ cone stamp – typical from Feb 1973 to Aug 1973
- Day of the month included in the date stamp
- ‘Hammered’ paint finish to the chassis – typical from Oct 1972 onwards
As I said earlier, this stuff might sound complicated but it really isn’t. You will pick it up fairly quickly just with a bit of experience. Also check out ‘How To Date Celestion Greenbacks‘ to learn about the most obvious features.