The MacKenzie Endless Loop Repeaters

By  Gary Avey

In the late 1950s more and more radio stations were adopting programming formats that were fast-paced requiring tight cuing of short segments of audio. There was a great need for some type of playback equipment that could handle these segments easily. This led to the development of the endless loop tape.

One of the first high-quality units of this type was the MacKenzie Repeaters from MacKenzie Electronics of Los Angeles. It had five magazines which were made up separately and could repeat individually. The unit had a single motor and a long belt driven shaft that drove all five slots. Each magazine had a pinch roller and could be started by its own push button switch. The recordings were made on any standard reel to reel tape recorder on a specially lubricated tape that was cut to length and loaded into a metal cartridge and then spliced to form an endless loop. The MacKenzie Repeater was the forerunner to the “cart” machines that became standard in radio for several decades.

(Click on images to enlarge the view.)

The MacKenzie Repeater magazines, or cartridges, could contain station jingles, news intro’s, commercials, sound effects or any short audio bite. The magazines could be changed in about 5 seconds. The start up was instant and the tape would play through and stop at the beginning ready to be played again at any time. The cuing was done by a silver sensing tape that was applied to the beginning of the audio segment. The conductive tape would close an electrical contact that stopped the tape loop.

In the late 1950s more and more radio stations were adopting programming formats that were fast-paced requiring tight cuing of short segments of audio. There was a great need for some type of playback equipment that could handle these segments easily. This led to the development of the endless loop tape.

One of the first high-quality units of this type was the MacKenzie Repeaters from MacKenzie Electronics of Los Angeles. It had five magazines which were made up separately and could repeat individually. The unit had a single motor and a long belt driven shaft that drove all five slots. Each magazine had a pinch roller and could be started by its own push button switch. The recordings were made on any standard reel to reel tape recorder on a specially lubricated tape that was cut to length and loaded into a metal cartridge and then spliced to form an endless loop. The MacKenzie Repeater was the forerunner to the “cart” machines that became standard in radio for several decades.

The MacKenzie Repeater magazines, or cartridges, could contain station jingles, news intro’s, commercials, sound effects or any short audio bite. The magazines could be changed in about 5 seconds. The start up was instant and the tape would play through and stop at the beginning ready to be played again at any time. The cuing was done by a silver sensing tape that was applied to the beginning of the audio segment. The conductive tape would close an electrical contact that stopped the tape loop.


 

 

 

MacKenzie Repeater closeups photos courtesy of Scott Rogers, Toronto, Canada


Advertisement  regarding the MacKenzie Repeater appeared in Feb. 15,1960 issue of Broadcasting Magazine.

 

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