BBC MX/29 passive mixer

Part of the OBA/9, the MX/29 incorporated 4 passive constant impedance attenuators.

Utilised across the BBC during the Fifties, the one in the photo below was the original mixer for the Radio One Roadshow which launched in 1967.

OBA 9 mixer

The Manchester Playhouse, home to the Northern Dance Orchestra, utilised an array of BBC OB equipment, including no less than 5 x MX/29s as seen on the RHS of the picture below


BBC OB Type 9 amplifier

EVE BBC OBA 9 in situ

The OBA/9 system evolved in the 1950s to replace OBA/8, with a smaller footprint and expanded facilities to meet the demands of outside broadcast engineers as the needs of broadcast expanded.

OBA 9 close up

The whole system was designed to be ‘portable’ of a fashion; consisting of an MX/29 passive mixer, OBA/9 valved amplifiers with high gain and power supply, along with monitoring amplifier and distribution facilities. Ancillary items included a loudspeaker LSu/11 and communication units CMU/9 and CMU/10