FS: Korg Monotribe Midi Kits

[altitude909]

So here is my no-solder, plug and play midi kit.

This consists of midi in and out on a surface mount PCB. Instead of midi jack, I am using 3.5mm TRS to DIN5 cables (included 2x 6ft Rean/Neutrik metal connectors) since drilling 2 small holes anywhere is a lot easier that 2 huge ones. You can do these holes with a hand drill and a 6mm bit. The jacks will be the threaded with a knurled nut variety, the ones pictures are for a mod i am doing and there for reference only.

$40 + shipping ($6 US, $15 CA, $17 worldwide)

Here is a very good write up about what the built in midi functionality in the montribe is capable of (and related quirks). I can only provide the hardware to interface with the serial header, I cannot change any of the firmware functionality

Gameboy Genius » Blog Archive » Monotribe, MIDI and me

Simple answer: You can sync the internal sequencer, play notes, and control all parameters the EG type as well as all parameters relating to the LFO section. It also transmits those very same things, so it could be used as a MIDI sync source, sequencer or limited control surface.

Details

Sync: It will both send and accept MIDI sync, start and stop messages, meaning the sequencer can be reset over MIDI, which can’t be done remotely if you’re only using the regular sync input.

Quirks/problems: When you’re using the miditribe as a MIDI slave and remove the sync clock, it will keep waiting for a MIDI clock indefinitely. You can fix this by either turning it off and on again, or plugging something in and out of the sync in jack, which will restore it to the internal sync clock.

Notes: It will send and receive notes within the limits of the sequencer. It’s using channel 1 for notes. Notes outside these limits will be ignored. It does not react to varying velocities. It does however react to pitch bend MIDI messages and is able to record and play back pitch bend in flux mode! I don’t have MIDI out hooked up at the moment, so I can’t confirm this right now, but I’m assuming it also transmits MIDI pitch bend messages when it plays notes in flux mode.

Quirks/problems: It has a stuck note issue when it doesn’t receive a note off message for a note. Let’s say you send a note on message for D4 and then a note on message for E4, and lastly a note off message for E4. This can happen in Renoise, for example. In this situation, D4 gets stuck, and a new D4 note is played as soon as you release all other keys. Sometimes multiple keys can get stuck, and you need to go through each key to depress each one.

Drums: It’s using the standard General MIDI specification for drums, which means the following notes on MIDI channel 10.


BD: Note number 36 / C1 Bass drum 1
SN: Note number 40 / E1 Snare drum 2/Electric snare
HH: Note number 42 / F#1 Closed hi-hat

Control change messages (CC): It can send and receive CC for all the knobs and switches marked green above. The parameters are mapped as follows:

Name CC number Values GM parameter name
LFO rate 16 – General purpose controller 1
LFO int. 1 – Modulation wheel
EG shape 80 32=decay
64=sustain
96=attack General purpose controller 5
LFO target 81 32=VCO
64=VCO+VCF
96=VCF General purpose controller 6
LFO mode 82 32=Fast
64=Slow
96=1shot General purpose controller 7
LFO wave 83 32=Saw
64=Triangle
96=Square General purpose controller 8

Quirks/problems: It’s practically useless as a MIDI control surface because it is really slow at sending CC messages. If you wiggle one of the knobs a few times really fast for a few seconds, it will continue to transmit CC commands for several seconds.

I’ve noticed that when controlling the LFO rate/int. knobs remotely, the value will sometimes jump back to the value that the knob is at. I’m guessing that this happens because there’s a small fluctuation in the voltage that the microcontroller will pick up as a change in the value. If you only want to control these parameters over MIDI, you can minimize this effect by turning these knobs fully counter-clockwise.