Anyone using their midi out?


I’m finally planning out a zynthian box and I’m trying to decide if I should bother with a midi out port? AFAICT there really aren’t any sequencers yet in the software list and I don’t have any other synths to send to if there were. Perhaps something cool could be made using the new pd sequencer modules I figure I can always use usb midi or qmidinet to record to a daw if I ever wanted too but I wanted to see what actual user experiences were.


I would plan for the second. I have mine connected as Through and cascade 2 Zynthians.
When we will have a sequencer or looper, an out will be useful.
IN only is not advisable.


I use the MIDI Thru as I don’t have a MIDI splitter yet, but I have other MIDI stuff (Yarns, SQ1, Volcas) and hopefully will have more in the future. I could see how it wouldn’t immediately be useful to you right now though, but I’d say might as well add them all now! :smile:


Currently the only available Zynthian’s feature that takes advantage from the MIDI-OUT connector is:

  • MIDI Router/Filter

But that’s going to change very soon. I’m working in a new MIDI router arquitecture:

that will allow new uses:

  • Improved MIDI Router/Filter
  • MIDI recording/replaying
  • MIDI looper/sequencer
  • MIDI clock

Kind Regards,


I just bought a DIN socket for my zynthian to finally get a midi out. Now I somehow can’t figure out where to solder that thing. In the wiki the midi out only seems to be mentioned in the newer versions of the kit. I have the kit from July 2017. It is possible to get the midi out for my zynthian?


It does work in default as a midi thru…


but where to the cables need to lead?


Hi @Hampelschwein!

If your zynthian uses the old “2-In-1” Module (probably it does because the first v2 kits were distributed in September 2017), there is no MIDI-OUT nor MIDI-THRU output. You have 2 options here:

  1. You build a separated MIDI-OUT circuit for your zynthian

  2. You change your v1 “2-In-One module” by the v2 version “All-In-One module”, that include the 3 standard MIDI ports IN/OUT/THRU.

Kind Regards,


alright, thanks

  1. is there a relatively easy way to build the midi out circuit? Is there some more or less step by step guide how to build and how to implement in zynthian?

  2. how much would this all-in-one-module cost me?


Although it’s really easy to build, i don’t know any step by step guide … Perhaps somebody in the forum know this guide??

Anyway, if you ask for a guide , probably it’s better for you to take the yellow tile road :wink:

It depends if you want to solder or not:



ok I just found this page.
If its really that simple, then a step by step guide I guess is over the top.
Is this something that would work for for Zynthian? He mentions that some circuits also use a driver or transistor switch.
Just not sure where I would have to put whats here called D1/TX in case of Zynthian/Raspberry.



This should work without problem. It’s a very common circuit.
The official All-In-One circuit uses opto-couplers for every MIDI port, but it’s not really needed at all.

Good Luck!


ok cool! could you just tell me about the D1? Whats the D1 in zynthian?


That schematic will works, but noone should ever use non decoupled MIDI connections unless he knows for sure every single device it will be connected to. Been there, done that, and destroyed an old Korg synth MIDI IN port.


D1 and the other Diodes in the MIDI circuit of the All-In-One are for protecting the optocoupler LED against inverse current/voltages. MIDI, at a hardware level, is a current-driven serial port, similar to RS485 or RS422. It’s designed for “long” distances (specification is for 15 m, but normally you can work with more). The “price” to pay is that you could have some inductance in the wire, and this could cause reverse-over-voltages when switching fast. Also, an external electric field could induce a current in the wire (noise) and damage the optocoupler’s LED. Again, i’m not an expert and people with deeper knowledge in electronic could offer a much better explanation :wink:

As @Axeman has explained, this simple MIDI-OUT circuit will work perfectly, but your RBPi / MIDI device will be “more exposed” to accidents.

Kind Regards,


Or you buy a 15€ USB Midi cable


and where is the actual soldering point in zynthian? I’m trying to find out where to actually wire midi signal into this midi out circuit

I already drilled a big ugly whole in my zynthian housing so I would prefer to use it for the midi jack instead using the midi cable, besides I’m interested in how to do this :slight_smile:


You need the rPI pin 8 (the UART TX signal), it’s in the schematic :slight_smile:


cool, thanks axeman!

How does the midi out circuit in this picture look to you? This should be a decoupled one right?


It seems ok. The 7417N will prevent the rPI GPIO unpleasant electrical encounters… :slight_smile: