KM 253

Common name: Neumann KM 253

Production Status: Discontinued / Vintage

The Neumann KM 253 is a special version of the KM53 with an RF-shielded 7-pin Tuchel connector manufactured from 1961 to 1964. Powering requirements and microphone specifications are identical to the KM 53. In 1953 Georg Neumann GmbH introduced the “KM” family with the KM 53, a miniaturized pressure (omnidirectional) condenser microphone. KM is the acronym for “kleinmikrophon” meaning “little 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.