Vintage speaker dating
Note: You might have read elsewhere that the month codes changed in 1963.
This is incorrect – they always went from A to M, skipping the letter ‘I’.
In most cases the first letter represents the month, and the second letter represents the year.The 6 digit code indicates what manufacturer made the speaker and when it was made. Here is a list of some of the speaker manufacturers and their EIA codes: So, the speaker in the image above would have been made by Jensen (220) during the 27th week of 1951 or 1961.The year is confusing because it is only a single digit.Notice the large font size and white manilla paper gasket. The font size is reduced from around mid 1965 onwards.The gasket material is made from cork with a thin paper overlay and is made up of 4 separate pieces.