Yamaha FX-20 as Virtual Organ Console

**rumpus** · 04-01-2010, 01:54 AM

At last I have finished programming my MIDI interface for the FX-20. Note that this is not a true midification of the FX-20 such as freddy2's device, rather it is specifically designed to drive a virtual organ such as Hauptwerk or Miditzer.

The circuit plugs in to various ribbon cables inside the FX-20 and does not make any other changes to the FX-20. The program in the interface can be uploaded via a serial port.

The interface has been working well for over three years, and is also installed in another FX-20 in Australia and in an FS-70 in Ontario.

The circuit provides unlimited polyphony on all keyboards and pedals, tailorable MIDI messages for any button push, button release and/or slider movement, and also MIDI messages for expression changes and pressure sensor changes.

In this incarnation the FX-20 can be played in its original form, or the FX-20 sounds can be played simultaneously with the virtual organ, or if all volume sliders are zero then only the virtual organ will sound. I have a regpack that stores silence in the 8 pistons for when I only want the virtual organ.

The main problem from the virtual organ point of view was that the LEDs on the console remained under FX-20 control, so they never matched the stops drawn on the virtual organ screen.

Now with the latest program update I can choose to run the FX-20 with all the LEDs and sliders controlled by the interface circuit and responsive to MIDI messages from the virtual organ to synchronize the LEDs to the virtual organ stops. (still no changes to the FX-20)

This marks the end of fiddling with the program and the start of serious organ practice.... I have a feeling the former was easier somehow.

cheers, dave

**FlametopFred** · 04-07-2010, 07:31 PM

This sounds like an awesome project ! Congratulations on getting things to work. Any photos? Video?

[quote user="rumpus"] The circuit plugs in to various ribbon cables inside the FX-20 and does not make any other changes to the FX-20. The program in the interface can be uploaded via a serial port.[/quote]

So is this an off-the-shelf circut board that connects to organ keyboards?

The circuit provides unlimited polyphony on all keyboards and pedals, tailorable MIDI messages for any button push, button release and/or slider movement, and also MIDI messages for expression changes and pressure sensor changes.

That part sounds very interesting.

**rumpus** · 04-08-2010, 03:41 AM

[quote user="FlametopFred"]So is this an off-the-shelf circut board that connects to organ keyboards?[/quote]

No, I custom designed the circuits, had them printed by futurlec.com and then did the soldering and made all the connecting cables.

The major work after that was programming the PIC micro-controller.

Not sure how to insert pictures.

**geoelectro** · 04-08-2010, 11:38 AM

Dave sent me some pics so with his permission, I will offer them up.

Here you go...

Geoelectro

**stephenphillips** · 05-02-2010, 11:08 AM

Hi,

Doing some homework on options for adding MIDI to a newly-acquired FX-20. This looks amazing. I am unsure of what the phrase "not a true MIDIfication..." means — the description of the unit's performance sounds pretty complete to me!

Availability, method of programming, user experience stories etc? Very keen to learn more.

Cheers,

Stephen.

**rumpus** · 05-02-2010, 12:15 PM

Hello Stephen,

a complete MIDI interface would allow the FX-20 to be played and controlled via MIDI messages from another instrument or computer. My circuit only provides MIDI Out from the FX-20 to a computer. This is perfect for my purposes, namely to control a virtual pipe organ. The other aspect missing from my interface is key velocity. I do not control the keyboard scanning matrix - I can only spy on it. The micro-controller in the circuit is not fast enough to handle all the signal changes.

Fredy2 elsewhere on this forum has mentioned an interface circuit he has made that uses Yamaha's own interface card (used for an optional MDR recorder) and thus obtains the FX-20 notes and velocites from the Yamaha itself.

As for programming, the circuit uses a Microchip PIC micro-controller and it is programmed using MPLab - a free programming environment provided by Microchip. I use a utility program (a spreadsheet would do just as well) to assign a MIDI message to each control. Then the program is re-compiled and uploaded into the circuit via a serial port.

I tend not to change the MIDI messages often because I can do that configuration in the target virtual organ software - Hauptwerk or Miditzer.

You will know that the Solo and Pedal on the FX-20 only play one note at a time. The native Yamaha MDR interface mentioned above allows 3 notes on these manuals. My circuit allows unlimited polyphony.