KM 53a

Common name: Neumann KM53a

Production Status: Discontinued / Vintage

KM is the acronym for “kleinmikrophon” meaning “little microphone”. In 1953 Georg Neumann GmbH introduced the “KM” family with the KM 53, a miniaturized pressure (omnidirectional) condenser microphone. The professional market request was for microphones offering the same quality as the U 47, M 49 and M50 with a very small size. These microphones were aimed at television broadcast and similar applications. At the time the smaller capsule available was the 21 mm metal film (aluminium) developed for the M 50. The target was to engineer a small tubular microphone not greater than 21 mm in diameter. It was designed around the Telefunken AC 701 k tube. The output transformer and all the necessary components were housed inside a very thin cylinder achieving a high grade of miniaturization for the times. The aluminium diaphragm was able to withstand the high heat coming from TV lamps better than a standard synthetic film membrane (e.g. PVC). The circuit received improvements during the time resulting in a KM 53, KM 53a and KM 53c exactly as it happened for the 54 and KM 56. The special “RF-proof” series are denominated KM 253, KM 253a and KM 253c. These feature a larger RF-shielded Tuchel connector and so are easily recognizable. Many accessories were available for KM’s such as different length capsule probes, in-line pad modules (Z 29) as well as standard, rack mount and battery-operated power supplies. The KM 53 microphone was used extensively for orchestra recordings and TV productions. The power supply units for these RF-proof versions can be identified by the letter “h” after the standard model number such as NKMh or BB9h.