Anatomy of a WurliTzer Theatre Pipe Organ
This is one of the few 3-stage actions in a WurliTzer Organ.
The magnet (top right), mounted upside down, exhausts the Primary Pneumatic (next to the
magnet) which lifts the internal valves which exhaust the Secondary Pneumatic (bottom left)
which pulls the external valves (top left) which inflates the Power Pneumatic (behind)
which has the Hammer attached to it.
The second stage valves have a spring between the top of the top valve and the nut on the
valve wire. In the off position the spring holds the top valve down such that there is a
small opening for the Power Pneumatic to exhaust through, which ensures the Hammer returns
relatively slowly and quietly. When the valves are activated the top valve seals quickly
and then the spring allows the lower valve to have greater movement which provides are larger
opening through which to inflate the Power Pneumatic as quickly as possible.