NSTRUMENTS | ELECTRONIC ORGANS | VACUUM TUBE DIVIDER ORGANS

The Wurlitzer 4000 is a vacuum tube chord organ manufactured in the late 1950s. Wurlitzer rarely reused model numbers, but the model 4000 was later used to designate a digital organ in the Omni line.

H. Emerson Anderson’s Electronic Organ Handbook (1960) includes a chapter on the Wurlitzer 4000 with schematics and a diagram of the chord unit. It appears that the chord unit is the same one that is in the 4250 (at least, it appears to have the same knob as the one depicted in a 4250 cyanotype).

The Electronic Organ Handbook also includes instructions on tuning the model 4000. It suggests connecting a Conn Strobotuner to the speaker output, waiting fifteen minutes for the tubes to fully warm up, and then first tuning the solo manual, followed by the chord buttons. The 4000 is not a divide-down organ. Instead, each oscillator sets the pitch for two or three consecutive notes, which means that the organ will not have polyphony for certain adjacent notes.

According to Anderson, the organ has a 41-note solo manual and 45 chord buttons. Instead of pedals, it has nine bass buttons.