text: Pipe-electronic hybrid organs (1930s–) Early combinations of pipe organs and electronic technology (including the electronic tone generators, at later) were developed in the 1930s. Custom electronic organ consoles occasionally replace aging pipe consoles, updating the electrical control system for the pipes as well as adding electronic voices to the organ. Even large pipe organs are often supplemented with electronic voices for the deepest bass tones that would otherwise require 16- to 32-foot pipes.
  For hybrid organs that combine pipes and electronic sounds, pipes change their pitch with environmental changes, but electronic voices do not follow by default. The frequency of sound produced by an organ pipe depends on its geometry and the speed of sound in the air within it. These change slightly with temperature and humidity, so the pitch of an organ pipe will change slightly as the environment changes. The pitch of the electronic portion of a hybrid instrument must be re-tuned as needed. The simplest method is a manual control that the organist can adjust, but some recent digital models can make such adjustments automatically.
  Electronic church organs (1939–)
  The first full electronic church organ was built in 1939 by Jerome Markowitz, founder of the Allen Organ Company, who had worked for years to perfect the replication of pipe organ sound through the use of oscillator circuitry based on radio tubes. In 1958, Rodgers Organ Company built the first solid-state, transistorized church organ, its three-manual Opus 1.