Midi interface for Organs, String Machines and Polyphonic Synthesizers

Description | Machines and manuals | Order online


OrganDonor is a universal midi interface for electronic organs, string machines and polyphonic synthesizers. It can be used to midify machines where other approaches fail. OrganDonor uses analogue switches to directly simulate keyboard presses. A large voltage range of up to +-20V allows interfacing even the most vintage machines.
In addition, parameters such as filter cutoff, glide or preset selection switches can often be interfaced as well.
The modular approach lets you add as many analogue switches as needed. This allows even large polyphonic synthesizers or organs with several manuals to be interfaced.


Currently we offer OrganDonor as customized versions for particular synthesizers. We are working on expanding the portfolio and creating more installation manuals. Contact us if your synth is not on the list yet, or if you want OrganDonor installed in your synth by us.

Additionally, the behaviour of OrganDonor is fully customizable via the OrganDonor configurator. This is a browser based tool that allows you to create midi assignments to analogue switches, digital outputs, PWM outputs and CV/Gate output (special OrganDonor version needed for CV-out).

organDonor installed in a Roland RS-202

List of machines and Installation manuals

Click on a Link to get to the specific installation manual. If there is no link, we think OrganDonor will work with this machine, but were not able to try it yet.
Your synth is not on the list at all? Contact us!


Korg PE-1000 (installation manual coming soon)
Korg PE-2000
Korg Lamda ES-50
Korg Delta DL-50


Roland RS-09
Roland RS-101
Roland RS-202
Roland RS-505
Roland VP-330


Yamaha SK-10
Yamaha SK-20
Yamaha SK-30
Yamaha SK-50
Yamaha SS-30


Arp Solina String Ensemble
Arp Omni


Elka Rhapsody 490
ELKA Rhapsody 610


Moog Opus 3
Moog Polymoog (not without modifications, as it uses SPDT key contacts)


Crumar Performer


Hohner/Logan String Melody
Hohner Stringer /Elka K4 / Elex K4


Vermona Strings
Vermona Piano Strings