ALTEC 639BMulti -Pattern Ribbon Model --1941-48
In 1941, ALTEC began producing the 639 series with the ALTEC
name on their models. The 639A/B was nick-named the
"Birdcage" microphone.This mic has been a regular feature in
elaborate broadcasting studios including the Voice of America.
Maurice Tarplin of the Maurice Tarplin Show