Leslie Half Moon Switch for Arturia - Weekend Project

As a Hammond guy, I’m so used to playing organ with a half-moon Leslie switch that I hate playing without one, so I usually try to engineer something to retrofit to all my live keyboards. My current gigging board is an Arturia Keylab 88 Essential, a great board but the Mod wheel is located at the extreme top left of the keyboard and that’s just too out of the way for Leslie switching, especially when you’re also playing bass with the left.

On this keyboard I decided the best way to achieve this was to emulate what the mod wheel does using a three way Telecaster switch via a resistor network.

These telecaster 3 way switches are perfect for this job, so I created the resistive network and wired it all up and tested to make sure I got the values right.

This circuit should work with any keyboard that uses a voltage divider to perform the task, you might need to alter the resistor network values to match. In my case the mod wheel potentiometer was a 10K linear.




:grinning: :raised_hands:
With my circuit certified working I tidied up the resistors and heat shrunk everything to keep it all together.

Next I printed out the half-moon case for the switch. Don’t ask why I chose red… it’sjust what filament I had in the machine at the time :stuck_out_tongue_winking_eye:

In hindsight, I reckon the red contrasts nicely against an all white keyboard :grinning:

The next step was really the hardest because the Arturial Keylab Essential 88 is so tight for space that I had nowhere to route the switch cables without them getting in the way of the keys - the keybed splits the keyboard in two complete sections. I had no choice but to do some non-reversible modifications to the casing which meant removing a lot of the plastic ribbing under the chassis to accommodate the wiring and then secure everything with hot glue - a service tech’s nightmare :rofl:

I screwed everything back up and viola!! I can now constantly fiddle with my Leslie speed like any self respecting Hammond freak :crazy_face:

Thanks for reading and have a great day! :vulcan_salute:


Nicely done. As I was never brought up on a traditional Hammond, I prefer a foot controller myself. :slight_smile: But a great project and “how to” for half mooners!

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Nice idea. I’ve been playing Hammonds since I was around 14 (54 years ago), and been exposed to footswitches, half moons, and other rigged switches. Fortunately, all my controllers have a Mod Wheel on the left side, which honestly, is no harder to use than a half moon to access. A mod wheel mounted horizontally also works very well. I’ve tried expression pedals, sustain pedals, foot switches, buttons and knobs, and still prefer a hand switch. I still occasionally get to play the real deal, and I really have no problem moving between half moon and mod wheel. I would however, have some initial problem with the Arturia drawbars being so far to the right hand side, unless it was used for the lower manual. I could adapt, but crossing hands would feel very unnatural for awhile.

Since I played in the era where many venues provided Hammonds, Leslies, and Pianos, I had to learn to adapt very quickly to what I was faced with. I seriously had to perform repairs on many of the ill abused relics before they were playable. I do remember in one venue, activating Leslie speeds by touching bare wires. I made it to a Radio Shack, and put a somewhat usable switch on it, just so I would avoid being shocked.




I can also do a foot switch to change between chorale and tremolo but the Arturia only has one pedal input and I need my sustain function because I usually lay a piano over VB3.

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A simple usb footswitch would work.

Luckily my Axioms and XBoards have the mod wheel right next to the lowest key because I’m having trouble getting used to using the foot switch I also have in place. Nice to have both though.

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