Stop action

Having remembered the organists settings and then responding to the press of a piston, some means is needed to move the stopkeys.

The choices are the direct application of electrical energy through a solenoid, to move the stopkey and thereby change the stop contacts, or to do so indirectly through an electro-pneumatic action where the prime mover (air) is signalled by the actuation of a chest magnet under the control of the combination action.

There is a tendency to replace console pneumatic actions wholesale with modern direct electric stopkey units, though some regret the loss of so much characteristic technology.

A very few instruments have so-called ‘blind’ actions where although stops are brought on electrically, the stopkeys themselves do not move.