Vintage effects and musitronics repair specialist Richard Lingenberg has created an open source 9 draw bar MIDI/ USB Host keyboard organ module that he shared to our forum.

The organ uses one Teensy 4.0 to drive the Rev. D audio board and one Teensy 3.6 to drive a ILI9341 touch display. The organ makes use of the Teensy’s audio libraries and built-in SD card reader to store up to 105 patches including 22 preset patches. It also includes settings for Attack, Hold, Decay, Sustain and Release.

A draw bar, as it usually appears on a traditional hammond organ, is a metal slider that controls the volume of a particular sound component such as a harmonic or fundamental of the note being played as it slides in and out. When the bar is fully pressed inward, the sound output of that component is zero or completely silenced. This allows the operator to selectively mix the sounds produced by the organ’s tonewheel. If you’re curious to hear what the organ sounds like, you can listen to a demo Richard put together on SoundCloud.