Korg Volca Modular Notes

I’ve managed to get myself a Korg Volca Modular and have been having a bit of fun playing around with it. I’m not going to do a review or get into the detailed specifications – there are loads of reviews online. I’m more interested in its hacking potential!

There is a lot of information online in various videos or articles, but I don’t always seem to find some of them again once I’ve stumbled across them, so I’ve decided to put up a list of various things I’ve found here for future reference.

This page is essentially a “Korg Volca Modular” set of bookmarks.

Warning! I strongly recommend using old or second hand equipment for your experiments. I am not responsible for any damage to expensive instruments!

If you are new to electronic music, see the Getting Started pages.

Official Information and Tutorials

Main Korg link for documentation:

Volca Modular Main Product Page on Korg – Introductory video and some sample patches.
Korg Volca Modular Downloads – Manuals, firmware, cheat sheets, patch chart, etc.
Five part ‘Getting Started’ tutorial videos.
Tony Horgan’s Volca Modular three part masterclass.

A note on the Volca firmware. There is a firmware update for earlier models that supports calibration of the CV input.

Note that with mine, when I followed the “get version number” procedure (power on with REC held) I didn’t quite get the exact LED response as detailed in the installation notes. The notes appear to suggest that the firmware version is indicated by alternating between the “micro-tuning / 9” LED and one of the other numbers – so “Clear / 4” flashes for v1.04; “Down / 5” flashes for v1.05; and apparently “Act.Step / 8” should flash for v1.08 – which is the latest at the time of writing to download.

For my, “Long / 10” is flashing, so I’m wondering if there is an even later version installed in newer units that hasn’t hit the web… I also get 6 of the knob LEDs lit up and Act.Step/Play is flashing too… If you know what that means, do let me know.

I’m assuming mine is fully up to date at this point, so having been through the firmware update procedure.

Non-official Volca Information

Here are some links to various guides and tutorials that I don’t think are official Korg, but still are really useful!

I note that Tony Horgan has a book out too “Korg Volca Modular – The Expert Guide” which looks like it might be worth looking into.

Volca Modular Hacking

Here are some DIY resources that have looked in detail at the CV/Gate input, the potential for MIDI expansion, and how to link into the internal patch wires too.

AudioWanderer: Things to do with the Volca Modular.
Adding Additional Capabilities to my Korg Volca Modular (four part series).
Syntherjack: Korg Volca Modular and Arduino.
sensai7: Volca Modular MIDI.
Syntherjack: The REAL Volca Modular Specs.
Syntherjack: Volca Modular Expander Thing.
Abominable Music: Korg Volca Modular as an audio processor?
Chris Lody: How To Expand Bastl Kastle & Volca Modular Using A Breadboard.

One thing that is particularly interesting is that there appear to be test pads and unpopulated header connections on the PCB for MIDI IN and OUT. From what I’ve seen, these must be 3V3 level UART RX/TX links, so an actual 3V3 compatible MIDI circuit is required to use them.

There is a kit available on ebay that uses spring-loaded header pins for a “solderless” fitting to the PCB, and sensai7’s repository listed above shows how to solder on a MIDI IN circuit based on a 6N139 optoisolator.

The Volca Modular also has a CV/Gate input via a 3.5mm stereo TRS jack socket, which apparently has the following spec:

Left (Tip): Audio or Gate signal: “clipped to +/-5V and scaled down to +/- 3.3V”.
Right (Ring): CV: “1V/octave signal (0 – +6V)”.

It is also possible to use a mono jack, in which case the same signal is sent to both channels.

I have to say it took me longer than it should have done to realise that symbol in the bottom left is a music note, symbolising a pitch output…

Somewhat bizarrely, in the “Volca as an Audio Processor” video linked previously, a (presumably) stereo signal is fed into the CV IN and routed through the synth using patch cables…

There are also 5V SYNC IN/OUT jacks too.

One thing a number of hacks talk about is the fact that there is no ground signal out of the Volca. But it is available on the GND connections of the CV and SYNC jacks. And apparently on the screws holding the front panel!?

Reinforcing the Basics

As a reminder to self, here are a couple of things I’ve found out whilst watching some of the above, which I’ve since realised were documented “out of the box” on the “Basic Patches card” but I just hadn’t spotted or read properly.

Modulator as a 2nd VCO. Both oscillators can be brought out by adding a patch cable from the modulator’s source output to the second LPGs, which can be triggered off the AHD function.
LFO Modulation: By linking up the output pulse of the rise-fall second function back to its input, the +ve output can be used as a LFO/periodic control signal for a whole variety of other functions.

Other notes as “reminders to self” (that will almost certainly grow over time):

When the sequencer isn’t running the “pitch” output of the clock is the pitch of the current playing note.
Don’t forget the default internal connections.
When there is an “audio input” indicator on the panel, that is just for the one connection – any others are typically gates or control signals.

Closing Thoughts

People seem to be a little “hot or cold” over these mini synths, but I have to say that so far I think I’m with most of the people in the above videos – I think it’s great. In particular for me, I do like the idea that I’ll be able to tinker around with it electronically too.

What would be really interesting is if I can find some ways to integrated it with my Educational DIY Synth Thing so I might do a bit of reading up around how I might go about doing that.

Kevin