This is Betty, the first of Strand’s System CD control consoles. Built in 1956 for the Palace Theatre in London, she ran the lighting for the shows there – including the original London productions of Cabaret, The Sound of Music and Jesus Christ Superstar – until 1980 when it was replaced by a Light Palette.
  
System CD was an evolution of the Strand Light Console ‘organ’ console; like Light Console it controlled mechanical Mansell Clutch dimmers, but unlike Light Consoles it had faders to allow states to be preset and then played back precisely; as the dimmers were rotated by their motor shaft – the speed of the fade controlled using a foot pedal – the system would release the clutch as each dimmer reached its preset level. Since the dimmers would then just stay there until next changed, this was effectively a tracking console; it also let the operator program groups of channels for instant recall to aid setting up or running shows.
 
System CD consoles quickly found their way into theatres in the West End and across the country, and in the new wave of television studios being built for independent television. In many cases they would not be replaced until the arrival of memory control systems.

Betty was located on a perch above the stage right (OP) wing. 

Group photo courtesy of the Historic Stage Lighting Collection

Letter from Jerome Whyte (January 1961)
From David W. Kidd Collection
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Palace Theatre System CD known as Betty
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Photo: System CD Console for Palace
From Frederick Brown Collection
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Photo: System CD Console for Palace - Close-up
From Frederick Brown Collection
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