Jen SX 1000 as hardware?

Hi. I have a broken Jen SX 1000. Do you think that it could be converted into a Zynthian box? I am proficient in HW and SW.

It seems to me that I would need to mod the box to add a screen. Introduce some SW to decode some I2C GPIO input and send it to the Zinthian SW as MIDI note on/off. And somehow utilise the knobs as MIDI controllers (ADC and similar MIDI messages)

I’ve not looked at the Zinthian GitHub SW so I’m not aware of whether this is viable. A simple Y/N answer would be good, so I know whether to persue Zinthian or to look elsewhere.

I must say, I like the list of features.

Hi @Davidnorman!

Yes. It could be done if you manage to convert the raw keyboard messages to MIDI (the Jen SX 1000 doesn’t suppport MIDI).

Zynthian UI needs a display, so you should add one to the Jen. Also, some rotary encoder will be recommended, althought you can use the UI with a touchscreen interface.

Currently is not possible to control the UI using MIDI messages, but could be implemented too.


Thanks for the info. My out of band question (email) was:

I have a broken Jen SX 1000. I am donating it to a school science club. I would like to help them make it into a working synth again.

Does your SW require a screen? If I wrote a keyboard to MIDI convertor could I get the keyboard to control your synth software? Likewise, if I were to make the Jen knobs into MIDI controllers, could I send those to the synth SW?

I wouldn’t mind adding a small screen to the box, at the expense of a couple of knobs.

I’m looking for something that is easy for 16-18 year olds to do - so some pre-prepared synth SW seems ideal, if the mechanism for controlling it is simple enough.

Seems like the SW could accept MIDI input from some other SW running on the PI. Other things, like some rotary encoders, could provide extra MIDI control.

How big does the display need to be? Would one of those Hitachi 4 line LCD modules be ok?

You can use any display that works with RBPi. If it’s a touchscreen, better, but it’s not mandatory.


Thanks. Good info. I’m thinking of mounting the screen in a box at the back of the unit.

Can the RPi run with a read only mounted flash disk? IE with a RAM disk for /var/run files and syslog going to a circular buffer in memory. There are articles on this. It would be possible if the s/w doesn’t do any writing to config files. Just thinking of the power off sequence…

The current SD image is almost “read-only”, but not completly. Some writing is needed to save presets and change configuration. Anyway, it would be possible to mount read-only. Try it, please :wink:

FYI, frequently i turn off my zynthians by unplugging the power connector and never got a corrupted SD.


Hi @Davidnorman,

indeed: it would be nice to have a read-only system. I used them in several other projects with a Raspi. But there are some traps to avoid: sometimes you want to store your configuration. So the system (or better a configuration partition) has to be mounted into rw and back to ro after writing. Also you have to build a installation wrapper which allows developers to install or change software. This is not easy and stable to achieve.

So the question is: Does it bring more stability and for what costs?

Currently I haven’t had any problems with hard power cuts - even not at Maker-Faire and 9 hours of running/playing/configuring.

Of course you can try this if you have time and fun. But getting this into a suitable system is IMHO not easy. If you have fun with system configuration you can givw a stable build of a RT kernel for Raspi a try - until now I failed twice :smile:

Regards, Holger

Thanks guys. If it is mostly read only then I doubt it would corrupt frequently. I guess a small read only partition can be mounted into an otherwise read only FS to store configuration data. Minimum corruption on power failure.

For the project I’m doing I’m not that bothered about firmware upgrade. I’m more interested in knowing that the SD card isn’t slowly filling up with log file junk and that hard power cycling won’t brick the device. Once I’ve finished helping some children build the thing, it will stay in the youth centre and I won’t be supporting it, so it has to be robust.

Anyway - sounds like that can work - so good stuff