Making Old Organs More Portable With MIDI

In the 60s 70s and early 80s, roadies would lug hundreds of pounds of musical equipment around to gigs. Although the 8×10 Ampeg bass cabinet wasn’t fun in the least, the absolute worst was the Hammond organ. These behemoths of tonewheel organs sounded great, but moving them was a pain. For better or worse, portable MIDI keyboards caught up with the sound quality of these old electromechanical monsters. Everything is still not right with keyboard players; a good set of organ foot pedals is still hard to come by. To solve this problem, [Jeremy] converted his old Hammond A-100 organ pedals to MIDI giving him all the feel and aesthetics of an ancient instrument without all the heft.

To transform the ancient A-100 bass pedals into a keyboard, [Jeremy] turned to the HighlyLiquid MIDI CPU. This small board provides a few dozen pins to wire up to switches and potentiometers. A new switch assembly was built for the bass pedals using a momentary push button switch under each key. These buttons are wired up to the MIDI CPU, and everything worked out wonderfully.

Although there’s no video of the newly portable Hammond organ in action (something off Zeppelin I, [Jeremy]…) there is a great Flickr photoset of the entire build. Awesome work, [Jeremy]

3 thoughts on “Making Old Organs More Portable With MIDI

  1. The Hammond pedal rack is a poor pick for this mod. Those push buttons may not be quiet or hold up long. I have a couple of Wurlitzer 25 pedals that have built in reed switches! A Thomas set is first up to mod into midi pedals. A full two octaves, but spinet length. I need to make feet to convert it to floor use , as it was fastened up under the organ. When finished, 25 pedals you can carry under your arm!

  2. Cool, but I agree that momentary reed switches are much better, they are sealed in glass (will remain clean which can be a problem since this is sitting on the floor) and can be wired on the fixed side while the magnets go on the moving parts (simplifies the connections a lot).
    I converted my aunt’s Kimball organ to midi so she could play using hauptwerk or an organ sound module using stuff form (you could also use stuff from

  3. Should use hall effect sensors. They’re silent and effectively last for ever.

    Some push button switches are only rated for a few KiloPushes.

    Reed relays last much longer, but cost much the same as hall effect sensors, so why not go for the real thing?

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