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How to read and understand speaker rim codes [message #15561] Mon, 10 September 2007 10:38 Go to next message
Jim Mayor is currently offline  Jim Mayor
Messages: 2
Registered: May 2009
Esquire
Here's a quick and easy guide to help you understand the rim numbers which reveal a speaker's manufacturer and its production date. We'll use my picture below as an example.

The speaker reads C10N C7438 5 on the right: which describes the model and its construction. But what about the 6-digit code 220438 to the left? That's the code that reveals the manufacturer as Jensen and the production date as the 38th week of 1964.

Speaker companies, along with other electrical manufacturers, were assigned EIA (Electronics Industry Alliance) codes which were used to identify their equipment. The 220*** portion of the rim code is the number assigned to Jensen. Other speaker companies were assigned different prefix codes as follows (to name the main ones of our hobby).

CTS 137
Cleveland 433
Utah 328
Heppner 575
Quam 270
Rola 285
Eminence 67
Pyle 1098
Oxford 465
EV 649
The last three digits of the rim code, ***438 display the production date. The "4" gives the last digit of the year of production. I knew the cabinet from which this speaker came and knew the decade to be the 1960's - therefore this speaker was made sometime in 1964. The "38" refers to the calendar week.

Therefore the C10N speaker above was made in the 38th week of 1964. Right about the time The Kinks were in the #1 spot w/ You Really Got Me. Neat huh?

A speaker with the code 285312 would be.........................a Rola made in the 12th week of 1963 (or '53). Still helps to know the equipment from where it came to make a spot on age determination.



Re: How to read and understand speaker rim codes [message #15562 is a reply to message #15561] Mon, 10 September 2007 13:50 Go to previous messageGo to next message
granch is currently offline  granch
Messages: 118
Registered: May 2009
Viscount
Great! Thanks a mint.
What is the code for Altec Lansing?
-Dick

Re: How to read and understand speaker rim codes [message #15577 is a reply to message #15562] Thu, 20 September 2007 07:07 Go to previous messageGo to next message
dB is currently offline  dB
Messages: 234
Registered: May 2009
Master
More information about the EIA 476-B - Date Code List and website on the EIA Codes List with A/L being 391.

EIA 476-B - Date Code Marking (the document)
http://electronics.ihs.com/collections/abstracts/eia-476-b.htm



Re: How to read and understand speaker rim codes [message #15578 is a reply to message #15577] Thu, 20 September 2007 20:42 Go to previous message
granch is currently offline  granch
Messages: 118
Registered: May 2009
Viscount
Thanks a bunch!
-Dick

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