Sunday, December 14, 2008

To MIDI a set of Hammond New B-3 Bass Pedals

Somebody went through the expense of buying a New B-3 from Hammond Suzuki and didn't want to keep the pedals. I can understand that, but it doesn't mean that I approve! Anyway, they sold the pedals online to my new customer who wants to hook them to his Hammond XK3c Organ keyboard.

Problem #1: The MIDI encoding for the pedals is part of the organ circuitry, and is not in the pedal assembly. All you get is a 15-pin female DSub connector on the pedal box. So it's not "Plug-n-Play."

Problem #2: He's about 1000 miles away from my shop.

Best Possible Solution: To create a portable interface that will bridge the gap between the stock New B-3 pedal board and any MIDI device.

How I did it:

1) I had to get the layout of the 15-pin female DSub connector on the pedal board from the New B-3 Service Manual. I finally found it, and had to use a strong magnifier to read the fine print. The pedal assembly has *some* of the electronics needed for the MIDI encoder.

2) I had to see if the 25/32 Bass Pedal MIDI Encoder card I had in stock would work for this application. So I called the manufacturer/engineer/main guy and explained it to him. He gave me a green light for the project.

3) Into the shop to find a 15-pin male DSub connector and some ribbon wire.

4) On a piece of paper, match the output pins to the input pins.

5) Wire the interface cable. Pack in a box with circuit board and wall-wart power supply and ship.


The nice thing is that I can duplicate this anytime I need to use a new Hammond pedalboard with a MIDI interface. It will probably work with most of the Hammond pedalboards from the 90's and 00's. Even the 32 pedal church versions. But I'll have to check the service manuals for each before I can say so with certainty.


  1. Whoa! What's all this? I am looking for a way to MIDI the pedals on my A-100, so I can play bass sounds (with sustain) through my synthesiser. Can you give me any info on this. Please e-mail me at

    I am interested in getting that 25/32 Midi encoder you speak of. If a set of contacts were added to the angle iron under the pedals, it might work.

  2. Hello, i am also interest by this circuit adapted for my A-100 :)

    Can you give me any info on this. Please e-mail at ->

    in advance, thank you

    a tiny French addict to hammond vintage

    1. This is not as easy as my blog post described. It's a totally different animal. I am currently working on a X-77 that will end up having all 25 pedals MIDIed. But I won't be altering the pedals themselves. I am doing all the changes inside of the pedal switch assembly, which is inside the bottom of the organ. That way I can use the existing contacts and busbars for the MIDI keying. Also I won't have to worry about someone ripping the outboard switches off of the pedal unit while moving it. I've seen some gnarly damage to outboard gear that doesn't quite make it through the doorway. Smack! Ouch.
      If you are interested further, let me know!