7 thoughts on “How To Add MIDI IN And MIDI Out To A Korg Monotribe

  1. I did the mod and it works wonderfully. **However** Initially I went the opto-coupler route using a 6n138 and the results were less than satisfactory, I'm not sure if it was the specs of the opto or the resistance values in the schematic, but I could hear midi noise (i.e. a 'zippering' sound when sending midi CC's. I tried re-working the values to no avail.

    Finally, after running tests and bypassing the opto circuit and going the 'quick and easy' route (using a 820 ohm resistor on the midi signal line, and tying the (nc) pin to ground) worked PERFECTLY!!

    I've built these midi input circuits before and have had no issues at all (this being my 5th). I have a feeling that either the Monotribe is extremely sensitive to input current, or the 6n138 simply isn't in spec with the Monotribe 3.3v to operate properly (Possibly the 6n136 or PC-900 opto would work better?).

    In any case, the simple route seems to be the best route for me on this one.

    After doing the mod, I have to say it's damn near shameful that Korg didn't add midi at the factory being that it's so simple. I haven't had any of the issues that were mentioned in the blog (stuck notes etc.) except for the sequencer issue (where the 'tribe' waits for midi clock once it sees it and must be power cycled to use internal clock.) As a modder, I felt guilty with this mod, as it's just so darn easy to do.

    I would have preferred that Korg scrap the internal speaker and battery operation and instead spend the $$ on implementing MIDI In. Also, Portamentoglide would be nice. (I'm sure that's on the horizon in the modding community…)

    Also, for you monotron moddersusers that were weary of the 'tribe' being plagued with a noisy audio output (like the Tron), fear not, that issue doesn't exist in the 'tribe'.

  2. I added the resistor an ground wire but do not know where to attach them on the midi side,
    i also soldered ir from the back side, where there is a serial connection with pins stickit out is this ok?

  3. I added the 820 ohm resistor wire and ground wire, but i soldered them from the back side of the PCB, where the pins stick out, should it still work? and to what pin does do each wire go to for midi in?

  4. ok, finally reopened, and soldered the wires to the correct pins on the correct side.
    I now have a wire coming from the pin second to top with an 820 ohm resistor (signal), and a wire soldered to the pin second to bottom (ground), these two come out and i have no idea what midi pins they are supposed to go to.
    any ideas?

  5. Hi! I’ve done the MIDI IN mod but it works just on one of my keyboards! The working one is a masterkeyboard, the others are a normal yamaha keyboard and a Microkorg. I can’t really understand why and why should it work on the masterkeyboards but non on the other ones! The problem is that the working one always had problrem on the midi out part so actually I can’t play my monotribe with any of my three keyboards? Did any of you have the same problem?
    Ps: I did the “easy” mod and I tried even to replace the 820ohm resistor with a 1k one, but nothing happened!

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