Mystery object

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The object is Strand IDM (Instant Dimmer Memory) control lighting console from the New London Theatre. The IDM originated in 1965 and this is one dating from around 1972 was one of the last produced.

Rob Halliday who will be giving a talk on Computers in Entertainment at TNMOC on 12 March 2015 gives us the story:

IDM - Instant Dimmer Memory - enabled the instant storage (in the original versions) of up to 250 cues, and then instantly recall them for playback in any order.

Two types were offered: IDM-R, which used rocker keys to adjust the level for each light, and IDM-DL, which used the fader handles more familiar from earlier, manual lighting controls.

Around 20 installations were completed, including the London Coliseum, the Canadian National Theatre in Ottawa, and Budapest Opera.

The console pictured is an IDM mkII, one of the last produced. It was installed in the New London Theatre (later home of the musical Cats, now hosting the play War Horse) during its construction. In fact, the IDM's magentic drum memory module is still in the theatre, since with the building complete it's impossible to get it out in one piece!

IDM mkII used a Sperry dum memory, 5bit dual D to A channel control cards in 20 channel crates, and a lot of power supplies to make it all work! Tally paper tape punch/readers were used offered for memory backup and archiving.

This console is now part of the Backstage Heritage Collection.

Book tickets for Rob Halliday's talk here.


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