RCA Type 77-A microphone

{{Short description|Ribbon microphone}}

The RCA Type 77-A microphone was a simplex (uni-directional) ribbon microphone, the forerunner of the RCA Type 77-DX microphone. The 77-A was designed Dr. Harry F. Olson 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.{{cite magazine|last=Woram|first=John|title=Sound Waves: 50 Years Of Studio Mikes|url=https://books.google.com/books?id=-iQEAAAAMBAJ&dq=rca+studios&pg=PT36|magazine=Billboard|date=18 December 1976|access-date=8 May 2024}}

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