Roland JX-3P Polyphonic Synthesizer

Someone recently suggested that I look into possibly making some additions to the JX-3P firmware.  Since the Organix/River and Kiwi-3P mods had already been done, I wanted to be sure I could offer something different before proceeding.   Here is the result:

New firmware for the JX-3P:

With the help of several JX-3P owners, I have developed an enhanced version of the v4 firmware.   The code requires using a larger (27128 or 27256) EPROM, and adding a wire to connect an additional address line to the CPU.   The Memory Protect switch must also be modified to not protect in the MIDI position.

Here are the new features:

1) MIDI CC (7-bit) control of all patch parameters

2) Velocity of MIDI notes can modulate either VCF envelope depth, VCA level, or both.  Setting saved in patch.   (Velocity implementation based on MKS-30 code, not a special mode like the "velocity EPROM" which Roland offered for the JX-3P.   Internal keys use velocity value of 64.)

3) Sysex save and load of bank B and C patches (compatible with MKS-30 patch save format)

4) MIDI channels 1-8 or Omni mode can be selected and setting is saved when power is off

5) Front panel and CC selection of Poly I or Poly II key assign mode (always defaults to Poly I at power up)

6) LFO delay timer works when playing using MIDI, same as internal keybed

7) CC 01 mod wheel messages now supported.   (Controls LFO -> DCO mod depth, same as MKS-30)

Here is a document which contains parameter CC numbers and information about the other new features.

Installing the new firmware requires performing two modifications to the JX-3P hardware.   Here are the instructions for doing this.


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