RCA model 74 ribbon Microphones

The  RCA model 44  series of high fidelity ribbon microphones were the “top of the line” in their day. Radio Corporation of America was in the business of making money so the audio division decided to design a less expensive version of their very successful model 44 that would appeal to a wider segment of the audio industry.

RCA Type 74-B   Bi-Directional Junior Velocity Microphone

Somewhere around the middle 1930s RCA came out with the model 74 ribbon mic (microphone). It was nicknamed the “Junior Velocity.” Velocity is another term used to describe a ribbon microphone. This refers to the way in which a ribbon mic picks up sound by the velocity or speed of air particles pushed by sound waves toward the mic.

The Jr. Velocity was a junior in size compared to it’s big brother. It was about half the size as well as being much lighter weight. The model 74 did not have quite the extended frequency response or fidelity of the model 44 series but it still was a very good sounding mic. It also did not have the rubber shock absorber or forked mounting of the 44. It had a unique ball and socket type stand mounting that allowed the mic to be tilted up or down toward the sound being picked up.

RCA’s Model 74B came out somewhere in the late 30s and was very popular. It was manufactured until, I believe, about 1950. The first 74Bs had a shiny chrome windscreen with a black bottom and then in the 1940s RCA changed the wind screen to a brushed chrome and the color of the bottom part to what they called “umber gray”. Umber gray looked more like brown to most people! The change in color scheme was necessary for television as they didn’t want shiny parts becoming a “glint” in the camera’s eye.

The model 74B cost less than half of it’s big brother the model 44. This mic was very popular with smaller radio stations, but even many larger stations used them especially for announcing and for indoor remote broadcasts because of their small size and light weight. The 74 was very much used on PA systems too due to it’s lower cost. Even though the quality of sound did not quite match the model 44 the Junior ribbon still had the smooth, clean sound typical of a ribbon mic.

Radio stations in the local area that used the RCA Junior Velocity included KBEE, KFIV, Modesto Jr. College (KRJC) radio and KYOS. The McClatchy stations like KFBK, Sacramento and KMJ, Fresno also used the 74B.

RCA KB-2A, “Bantam” velocity

Around 1950 RCA replaced the 74B with the  KB2 “Bantam Velocity”. This mic was much smaller than any previous ribbon mic. The Bantam used much stronger magnet material that came out of WWII, this allowed the smaller size. The actual case of the mic was part of the pole piece of the ribbon magnet. Another name for the KB2 was “paint brush” because it had a built-in handle that made it look very much like a small paint brush. Inside the handle, under a cover piece, was an “XL” type connector. The “XL” connector was made by Cannon Electric Co. of Los Angeles which would later bring out the “XLR” connector that everyone knows today. RCA claimed that they commissioned Cannon to make the “XL” connector especially for the KB2 series of mics.

In about 1954 RCA replaced the KB2 with the SK-46; this also was a relatively small size ribbon microphone that RCA continued to manufacture until they stopped making mics.

RCA SK 46

 

RCA BK-11

RCA brought out one more bi-directional ribbon mic before they went out of the broadcast audio business. Actually this mic, the BK-11, was to replace the 44BX. It is about the same size as the Junior Velocity but with a more curved, modernistic shape, it also has a swivel mounting on the bottom. The BK-11 is an excellent quality mic like the 44BX. This mic is still seen once in a while on Ebay but I don’t think RCA sold as many of the BK-11 as compared to the model 44s and 74bs…which are seen all the time on Ebay.

 

 

Until next time…this is Mr. Microphone signing off for now. I’ll be happy to answer any of your questions! See the link below.

 

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