Adding MIDI OUT capability to the Volca Keys means an already great little (and cheap) instrument can also be a really hand tiny MIDI controller and sequencer, so you can use the Volca sequencing to control any sounds you like.
There is a bit of information about this easy modification online but not much that relates specifically to the Volca Keys rather than the Bass or Beats. The electronics involved are really simple, the more complicated bit is making a midi socket actually fit somewhere on this compact little case!
Here’s a video showing my modded Volca Keys controlling Logic’s EXS 24 Sampler Instrument – but you could use it to control any MIDI controllable hardware or software. In this case the sampler is playing samples of my vibraphone. You can see me use MIDI Monitor to show the incoming MIDI messages from the Volca Keys – this is a really useful free program.
See below for how to do the mod yourself.
What you need:
- a 5 pin MIDI DIN socket (such as this one)
- some wire
- a drill to make the holes in the front panel and preferably a step drill bit
- two small nuts and bolts to hold the MIDI socket in place
- a needle file, small screwdriver, soldering iron, solder…
- some heatshrink tubing if you like
Remove the batteries and unscrew the three countersunk screws across the top, the three across the bottom and the one in the middle. They’re marked in this photo with yellow circles:
Now carefully open the Volca Keys as the four wires connecting the batteries and the speaker to the PCB are a bit fragile. Don’t worry if you do break them from the PCB though – I did this a couple of times and it’s easy to reflow the solder and stick the wires back in. It will look like this:
Now we can see the three points that we need to connect to a 5 pin MIDI DIN Socket – just underneath the brown and orange wires you can see points marked TX, VD and GND.
Use a flathead screw driver or something similar to tease the white plug all those brown wires are going into out of the white socket and unscrew all the screws on this PCB marked with a white circle.
Remove the mode and footage/octave selector knobs from the front panel and the PCB should come apart from the front now.
I want to put my MIDI out socket next to the MIDI in socket but there is limited room between the panel and the PCB to squeeze it in so I’ve made a spacer using an old plectrum, it’s about 1mm thick. I drilled three holes for the MIDI socket in it and trimmed the outer edge. It would be easier to just use a washer or spacer, I think 16mm would fit around the DIN socket, but I couldn’t find one lying around so knocked this up. You could use anything, you just need to raise the socket slightly up above the front panel.
Next I marked and drilled the large hole in the top panel for the MIDI socket. I used a step drill bit – these are REALLY handy for making holes like this, check them out here. I think the hole is about 16mm but with step drill bits you can just keep going until you get to the right size – very useful as it saves having loads of slightly different sized bits.
Next I filed down that raised plastic lip to make room for the two holes for the nuts and bolts that hold the midi socket in place, then drilled the two holes, fixed the socket in place and bent all the legs slightly – again just to make it fit between the front panel and the PCB once we put this thing back together.
Cut three lengths of wire to go from this socket to the points on the PCB we saw earlier. I used this 0.6mm solid core wire because you can bend it and it will stay in place, which makes soldering the connections easier. I also used heatshrink tubing over the connections, partly to make sure we don’t get any short circuits but mostly to appear professional in this blog post. The lengths of wire need to be about 15-20cm long I think – best to give a bit of extra length so things are easier if you want to open the Volca Keys up again in the future. I’ve labelled which wire will go to which connection on the PCB below:
Now slip this back into the front panel and put back all the screws in the holes marked with white circles. You need to remember which of the three wires is attached to which of the three legs on the MIDI socket. You could use different coloured wires or mark the loose ends of the wires.
Now solder the three wires to the three points we identified earlier and tuck the excess wires underneath so they don’t get in the way in between the keyboard and the battery compartment when we put this back together.
Put the whole thing back together and put those seven countersunk screws back in place. Put the two knobs back on the pots on the front – put batteries in or connect a power supply and test!
It sends MIDI clock based on the tempo, and all the pots send MIDI CCs except for PEAK, TEMPO and VOLUME. PLAY sends start and stop messages. Here’s a video with the pots assigned to controlling the settings of the sampler instrument:
And here’s a handy image and a reference table for what MIDI Control Changes the different knobs send with the decimal numbers and standard names:
|Mode selector||40 / Balance (fine) / the six positions are 11, 33, 55, 77, 99 and 121|
|Footage / octave selector||41 / Controller 41 / again the six positions are 11, 33, 55, 77, 99 and 121|
|VCO DETUNE||42 / Pan (fine)|
|VCO PORTAMENTO||5 / Portamento time (coarse)|
|VCO EG INT||43 / Expression (fine)|
|VCF CUTOFF||44 / Effect control 1 (fine)|
|VCF EG INT||45 / Effect control 2 (fine)|
|LFO RATE||46 / Controller 46|
|LFO PITCH INT||47 / Controller 46|
|LFO CUTOFF INT||48 / General purpose 1 (fine)|
|EG ATTACK||49 / General purpose 2 (fine)|
|EG DECAY / RELEASE||50 / General purpose 3 (fine)|
|EG SUSTAIN||51 / General purpose 4 (fine)|
|DELAY TIME||52 / Controller 52|
|DELAY FEEDBACK||53 / Controller 53|
|TEMPO||Doesn’t send a CC but changes MIDI CLOCK speed|