My MIDI / Schober Project


This is a non-commercial project. Neither the hardware nor the software design is intended to be sold. It is copyright (C) 2002-2007 by Peter A. Stark, but you have permission to use any of this information for your own use. You also have my permission to distribute this information to others, with the condition that you retain this copyright notice with all copies so distributed. You may include this design and information in any other projects, with the conditions that any such projects also retain the same copyright notice, and that you grant to others the same rights as this copyright notice grants to you.


The information below describes my particular organ conversion; although you are welcome to use the circuitry and ideas herein for your own purposes, you need not do everything exactly the same as I do. In some respects, your project may be simpler -- or more complex -- than mine, and you may want to or have to modify things. That's fine -- that is the great advantage of an open and fully documented system. For example, in my organ, there are four identical encoder cards, but they have three slightly different software variations, depending on their use. That's strictly because I happen to have some extra hardware in my organ and I need a little more versatility; most people using this approach would have the same software version in each card.

For example,here's how Bob Kinner adapted the system to his Rodgers organ.

This page was last modified on January 10, 2009.


I am converting an old Schober Theatre Organ --  a 1960's and 1970's digital musical instrument that used all discrete components and was sold as a kit --- to a more modern 2000's-style system that uses MIDI and digital circuits. This and the following pages describe the project and document the hardware and software used.

My own organ conversion consists of the following; someone duplicating this project could simplify it by eliminating the second swell shoe, the Roland module, and some of the audio circuitry:

The following block diagram shows the basic data flow between the various modules in my system; not shown is the audio processing and reverb that is also part of the system.

Click on each item below to get further information on individual devices in the above block diagram. The MD-1 and MD-2 cards are build-it-yourself printed circuit boards; all the info you need to build them is given in the referenced web pages.

The photo shows how some of these components are mounted. The picture shows three MD-1 cards on the side panel (at the top of the photo), then one MD-1 and two MD-2 mounted below, the 8-to-1 merge box against the rear panel (at the right of the photo), and the Roland CM32P sound module closest to the camera. The thick colored wires (yellow, red, blue, grey, and white) are MIDI cables; some of the thin wires to each board are power lines from a common wall-wart, and two of the thin wires are RS232 wires that carry velocity info from the two MD-2 cards to two of the MD-1 cards.



As mentioned above, this is a work in progress. If you have any questions, comments or suggestions, feel free to contact me: email to



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