did you know?

For one of the several German U-boats sometimes referred to as U 47, see German submarine U-47 The U 47 was a large-diaphragm condenser microphone manufactured by Georg Neumann GmbH during the years 1949-1965. Neumann U47 Tube The U 47 used the M 7 capsule originally developed for the CMV 3 microphone ("Neumann bottle"). Its PVC membranes unfortunately tended to dry out with age, however, and in 1960 the M 7 was superseded by the K 49, a capsule with similar acoustical design but membranes made of age-resistant biaxially oriented PET film. The U 47's circuitry was based on the Telefunken VF 14 M vacuum tube (a specially-selected VF 14; the VF 14 was an RF pentode for various functions in military field radios[1]); the discontinuation of the U 47 was caused primarily by the decision by Telefunken to halt production of the VF 14. In some ways the functional successor to the U 47 was the U 67..