Originally located in Chicago, Illinois, the company built a reputation during the 50s and 60s providing speakers used mainly in guitar and bass amplifiers.
Jensen and Rola were, for a time both under common ownership (subsidiaries of the Muter Co.), and shared various design similarities.
The company gained popularity in its early years, rising to its peak in the mid 1940s when Jensen speakers were selected to be used in the first production of a guitar amplifier by Fender Musical Instruments Corporation.
The company also produced Hi-Fi loudspeakers for home use and was a manufacturer of OEM drivers for other brands.
Following that demand, SICA Altoparlanti began reproducing "reissues" of the Jensen speakers in 1996.
In the '40's, Jensen would sometimes omit the leading zero of a single digit week, which would reduce the total number of characters to 5.