The RCA

RCA

RCA Corporation, founded as the Radio Corporation of America, was an American electronics company in existence from 1919 to 1986. The RCA trademark is currently owned by the French conglomerate Technicolor SA through RCA Trademark Management S.A., a company owned by Technicolor...

 Type 77-A microphone was a simplex

Simplex

In geometry, a simplex is a generalization of the notion of a triangle or tetrahedron to arbitrary dimension. Specifically, an n-simplex is an n-dimensional polytope which is the convex hull of its n + 1 vertices. For example, a 2-simplex is a triangle, a 3-simplex is a tetrahedron,...

 (uni-directional) ribbon microphone

Ribbon microphone

A ribbon microphone is a type of dynamic microphone that uses a thin aluminum, duraluminum or nanofilm ribbon placed between the poles of a magnet to generate voltages by electromagnetic induction...

, the forerunner of the RCA Type 77-DX microphone

RCA Type 77-DX microphone

-Type and manufacturer:The RCA Type 77-DX microphone is a poly-directional ribbon microphone, or pressure-gradient microphone, made by the RCA Corporation from 1954 until 1960, replacing its predecessor, the Type 77-D. Its design has inspired a stereotypical microphone icon...

. The 77-A was designed Dr. Harry F. Olson

Harry F. Olson

Harry Ferdinand Olson was a prominent engineer at RCA Victor.Harry F. Olson, a pioneer in the field of 20th century acoustical engineering, was born in Mount Pleasant, Iowa to Swedish immigrant parents...

in the late 1920s or early 1930s; prototypes are rumored to have existed in 1929 and 1930, but the 77-A was not announced until 1932.

The 77-A would set the standard for all other RCA ribbon microphone comparisons for the next 40 years.

Construction

It featured an acoustic labyrinth inside the case and two vertical in-line ribbons which enabled it to be uni-directional.

External links

• RCA Type 77-A information from www.coutant.org