JX-3P MIDI Expansion


Please note: this product is discontinued.

MIDI expansion for the JX-3P synthesizer


  • real-time control over all JX-3P parameters with standard MIDI CC messages (from a sequencer or MIDI controller)
  • loading new patches into the JX-3P via MIDI
  • selectable MIDI receive channel (1-3)
  • velocity sensitivity (via MIDI)

Additional for owners of PG-200 (or DT-200) programmer:

  • simultaneous control via MIDI input and programmer
  • transmission of MIDI CC messages from programmer, for recording in sequencer, or controlling other MIDI devices

Out of stock



Please note:

  • This kit only works with the JX-3P (not the MKS-30)
  • This kit does not change the sound of your JX-3P, it only adds new ways of controlling it
  • This kit requires entry-level soldering skills and careful following of instructions
  • This kit does not require additional parts, but tools are needed for montage
  • Placing this kit requires you to cut 2 PCB traces on the JX-3P’s MIDI board, but is otherwise non-destructive. Undoing the installation and bringing back a JX-3P to its original state requires these traces to be reconstructed (e.g. with wire links).
  • Installation can be done for you by River Creative Technology upon request (as a paid service)

I’m a big fan of vintage synths (surprised?), but as technology progresses, shortcomings in the original design become more apparent (e.g. no velocity sensitivity!). The Roland JX-3P is a great sounding synth, but lacks intuitive access to its parameters for those who haven’t bought a PG-200 controller. And those who have, experience restrictions in its use. In modern instruments nearly all parameters can be easily controlled over MIDI, automated from a sequencer, controlled from another keyboard, etc. Not so with the original JX-3P!

The JX-3P MIDI expansion kit aims to give you Roland JX-3P synthesizer a fresh upgrade. It provides MIDI CC control over all sound parameters, so you can control it in real time from a sequencer or another MIDI controller. This also allows you to upload new sounds directly via MIDI. It makes the JX-3P sensitive to velocity if you control it over MIDI (can’t change the keyboard). If you own a PG-200 it adds MIDI CC output to it, so you can record changes of parameters in your sequencer, or control another MIDI device with it. And it allows you to control the JX-3P from the PG-200 and MIDI input simultaneously. The complete MIDI specification can be found in the manual (see side bar).

The JX-3P MIDI expansion kit comes pre-assembled and tested, but you have to install it yourself in your JX-3P (which itself is not included!). This requires a little bit of soldering skills, nothing too complex. It also requires you to carefully follow the provided instructions (see side bar). Feel free to ask advice it you need it. Following the instructions, upgrading your JX-3P will be a rewarding experience, with many addictive synth-playing hours ahead.

A brief history

Originally known as the “Organix JX-3P MIDI expansion kit”, this the expansion was produced by hand by its developer (not me, for a change!), but increasing demand resulted in an ever growing waiting list of JX-3P fans. Initially being one of those fans, I got in touch with the developer, and learned that (1) he’s a great guy, and (2) he developed something really good out of genuine love for the instrument. I felt like supporting that and offered my experiences with production, and proposed distribution via the River web shop (freeing his time to develop more cool stuff!). He agreed, and here it is! We plan to keep in close contact for providing support and are open to suggestions for (potential) future updates.

Please note:
  • Roland is a registered trademark of Roland Corp. US
  • River Creative Technology is not associated to Roland Corp. US