MIDIbox of the Week (Button/Drawbar controller for Boehm Organ made by Crypto)

[TK.]

Crypto71 developed a special application to midify the buttons and drawbars of an old Dr. Böhm CnT/L organ.

He wrote:

today I finished building my first MIDI box project.

I have converted a Dr. Böhm CnT/L into a wonderful MIDI controller.

You can see the organ on the pic.

These organs were sold as a kit and this particular one was originally made in

1978.

I took out all of the former circuitry and kept only the drawbars, knobs and

buttons - of which desoldering was a real pain...

The keyboards (upper, lower, pedal) had already been wired up with a genuine

Böhm MIDI controller board. The button panel on the top right position

controls it (select sounds, change channels, volume, banks...).

Now for the interesting part:

- I have used 1 core module, 2 AINx4 modules and 4 DINx4 modules.

- The LED panel displays which button/drawbar etc. was moved and what is it's

actual setting.

- The white switches in the top middle are for switching presets.

- The small white buttons in the top middle position are for user settings

(any function one would like).

- The drawbars use sliders that are too long for the mechanical case, that

means, their pathway cannot be used fully. I had to scale the value so that

they now give values from 0 to 127.

- The single black slider between upper and lower keyboard is a kind of

modulation wheel.

- The four switches on the right bottom side are for fixed octave switching of

the keyboards and the pedal, and sustain ("foot"-) switch.

- The white pushbuttons and switchbuttons located in the front I want to use

for switching rhythms of a drum program.

Barely visible on the pic: the old foot pedal for setting the master volume is

also there and it has two footswitches mounted.

The Böhm MIDI controller panel and MIDI box both connect to a USB sound

adaptor inside the organ, and that connects via custom-made USB-wire to my

notebook. Both controllers run on the same power supply.

The notebook plays via SPDIF to my external amplifier.

On my notebook I have linux running, and even that can play VSTI instruments.

The B4II nicely runs on it and it can be controlled via MIDI box.

Thanks for making all of this possible with your work.

Full View

[stryd_one]

Excellent :) I'd love to see pics of the inside!