Roland Super JX-10 rebuild

[Craigyb]

This is my build and redesign of the Roland Super JX-10. I bought the guts of a JX from eBay, 2 voice cards, back panel, assigner board, power supply and wiring loom.

First I made a front panel and go the synth to boot and make sounds. Then I added the Vecoven V4 PWM upgrade to the voice cards and assigner from Vecoven.com. An OLED upgrade from supersynthprojects.com and a new switch mode PSU made up from parts.

I built the editor to talk to the JX over sysex, but that meant I had two displays, two encoder wheels etc and many other duplicated buttons. So I watched a video on controlling an MKS-70 over serial from a PC VST. I realized the JX sound cards are self contained 6 voice synths that just receive serial messages at the same speed as Midi, this means you can bypass the assigner board and talk directly to the voice cards to make sounds etc.

I created my own assigner board based loosely around the JX functions, I have the arpeggiator, chase mode, patch, tone and bank storage, sysex dumps can be received over midi or usb. I copied a lot of the JX menu layouts when using the OLED upgrade so I get double lines of parameters etc. The assigner is a Teensy 4.1 which uses i2c to talk to the display and buttons/LEDs. The pots are read on a 64 channel mux.The keyboard is a CME UF-70 cut out to house the synth. Unlike many JX-10's it has a fully working aftertouch. I got rid of the C1, C2 sliders as all functions can be edited via the front panel or a menu, but I kept the CV inputs so when assigned you can use foot controllers on C1/2.

Still some work to do, make the slider LEDs work, fix a few bugs and features that I've not implemented yet. But it's pretty close to a JX 10 you can edit.

 

[Moogulator]

impressive work. did you do it for educating yourself or because you wanted it more usable, better?
just curious. since it is not your first one.

 

[Craigyb]

impressive work. did you do it for educating yourself or because you wanted it more usable?
just curious. since it is not your first one.

It just seemed more sensible to create a new assigner board because it was too complicated to have the two displays etc. I did run the assigner board headless for a while with no front panel or display etc attached, but that meant I was missing things like the tune menu etc. So I went from editor to Roland assigner, editor to my assigner, editor to headless Roland assigner and then back to editor and my assigner. It was a huge learning curve as I wanted to import the existing sysex banks, these sounded awful until I spent some time analyzing the data properly. The V4 Vecoven actually has 4x 5 stage envelopes, but only uses 2 of them and 2 standard ADSRs, but you have to set the values of the unused parts of the envelopes when converting from the older ADSR based envelopes to the new ones.

The editor will also control other JX/MKS synths over midi and edit them with sysex.

 

[sospro]

WOW...It looks very chic. I wish you continued success with your ambitious project!

 

[fanwander]

That is really impressive work! How long did it take?

 

[Shunt]

This is pure passion. Wish you the best with that, very impressive!

 

[Moogulator]

The editor will also control other JX/MKS synths over midi and edit them with sysex.

means. it is compatible?

 

[Craigyb]

That is really impressive work! How long did it take?

Hard to say as it was an on and off project as I grappled with the complexity of it, I think I built 3 other polysynths and a few editors whilst I was working this one out.

 

[binary tubes]

Wonderfull Work.

I wait for a Monolog, with the RolandFanBoy, @Moogulator.