[Lucien Nunes]

This is true of most automatic music players; even if the motive power is electric, the action is pneumatic, which offers a combination of speed, lightness and compactness. So much so that the Hammond B-A roll-playing electronic organ, although completely electronic as an organ, still employed a pneumatic roll-player action. One notable exception was the Mills Violano Virtuoso, an entirely electric roll-playing violin and piano that operated at 110V DC throughout, a feature mentioned prominently in their advertising.

Cinema organs, on the other hand, contain a complex mix of electrics and pneumatics, with the electrics operating on voltages in the 10-24V range. Some types of cinema organ electropneumatic relay are contained within glazed wooden cases, although rather different to this one as they are sealed and charged with wind. The windows enable the action to be inspected in operation, which is not possible with the cover removed due to the need for wind pressure.