I'm not certain, but these horns look like they were made by Federal Signal Products. I tested them by simply connecting them to our home stereo system.

vintage speaker dating-33

These are codes often seen stamped on components found in US made vintage tube equipment.

This list is circa 1955, and some codes have been reassigned or added since that time.

Code formats were not completely standardized, but a little deciphering will generally yield the info of interest.

Note that many makers also stamped OEM (Original Eqipment Manufacturer) part numbers above or below the EIA code, in some cases parts makers or the customer elected not to include the EIA codes, so not all parts have them.

This awesome pair of Sound-Craft vintage horn speakers will cut through any noise with serious power.

Two classic steel siren horns in Machine Age putty gray are mounted on a pair of heavy duty professional aluminum tripods that adjust from approximately 20 inches to 52 inches.

Everything fits inside a custom-designed rugged portable case.

These vintage horn speakers were assembled by Sound-Craft Systems "Atop Petit Jean Mountain, Morrilton, Arkansas, USA".

They generally follow the following format: (example) 322 5904 where 322 is the manufacturer code (in this case Tungsol), 59 is the year (1959), and 04 is the week.

One alternate scheme is: 274 940 274 is the EIA code (RCA) 9 is the last digit of the year (in this case 1949).

Usually single digit date codes are from the 1940's, but have on occasion shown up in later decades, even up to the 1970's.