Thursday, 22 September 2016

Korg Volca Bass MIDI OUT Mod

Korg Volca Bass MIDI OUT Mod

There's a fantastic how to guide on how to add a MIDI out connector to the Korg Volca Keys over on Marcus Hamblett's website;

To get the MIDI connector to safely fit without touching the PCB behind it I had to add another pair of bolts to raise it up slightly, as shown here;

...But it's not really noticeable, and I'd rather the connector go on the front than the side so it can still be used while in the stand.  If you attempt this mod, you must make sure your MIDI connector isn't touching the other PCB otherwise you'll probably short it out.

Overall it was a pretty easy and speedy mod, although I did have my heart in my mouth thinking I was going to write off the Volca.   That's probably because I'm pretty cheap.   There was no need to worry though as it thankfully worked without problem.  Just remember to work with the batteries taken out as I'd read about another guy on a forum doing this mod and had blown a SMD fuse (aka very hard to solder in a replacement).  Good Luck!

Wednesday, 14 September 2016

The Abandoned Synth Project

Older Synths: The Abandoned Synth Project

2013-ish.  This was my first attempt at putting a synth together without copying someone else's design.  Essentially it's lots of modules that have been cobbled together, so I was still copying other peoples designs, but I'm pretty certain these circuits have never been assembled in this configuration before (that counts, right?).   Hearing how they interact and the effects of differing placement of modules was a fantastic learning experience, even if it perhaps didn't sound the best...  very reedy sadly, but for a first attempt that's not so bad I suppose. 

The CD40106 oscillator was from this hackaday article, but at this point I'd figured out how to make it tunable/playable with the array of resistors and switches.  I still hadn't fully figured out the best wiring for the AREG but it did 'mostly' work.  The beast contained;

x2 Oscillators (from a CD40106)
x1 PT2399 Delay
x1 Amp
x1 Fuzz (Bazz Fuss)
x1 12db Filter
x1 1-octave Keyboard (3 octaves selectable Low/Med/Hi) 

It's a project that I'd like to go back to, but many of the wires have since come apart from the breadboard so in all honesty it'd probably be quicker just to start from scratch.  If I were to re-do it, I'd add selectable waveforms (this version was only square waves) and possibly a second filter with a proper ADSR.

Thursday, 8 September 2016



This is a great little one-day project that can be pretty useful if you control your instruments over MIDI.  Basically this box allows you to send 5 different MIDI signals over 1 output.  So you can have a PC with 5 midi tracks, send it over 1 midi output to this box where the signal is then split into 5 outs, which you can then plug in 5 synths and have them all play nicely together.  

There are better descriptions on the internet I'm sure.

I found the original schematic here on the highly liquid forums;

I made a couple of small changes to the schematic; instead of running it from the mains I figured it was low power enough to run it from a 9v battery, so from there I added an on/off switch, and to be fully sure I didn't leave the battery on, I also added a red LED.

To get it all to fit onto one breadboard I first drew out the schematic onto some graph paper.  This was my 3rd attempt and I'm sure you could have a more efficient design, but this was good enough for me and I guess it maybe of some help to somebody else out there;

The plastic enclosure/project box came from Conrad for €3.09;

Here the on/off switch and LED can be seen;

Cable ties make everything look neater;

Monday, 5 September 2016

Introduction To Algebra / EdX

Introduction To Algebra

I hated maths at school, but the further I get into synth DIY I've released how important they can be, and actually they're kind-of fun when you have a purpose for them.  I hated seeing the maths involved and not fully understanding what was happening, so I took this online course and I can say it's brought me up to speed  This EdX course is a nice little (re)introduction to Algebra, and if you're not up to scratch with your maths, I'd fully recommend it.

Thursday, 1 September 2016

EE40LX: Electronic Interfaces: Bridging the Physical and Digital Worlds

Course Info;

A little while ago I finished the Berkeley / EdX EE40LX: Electronic Interfaces course.  This was my final submission;

The course itself was actually pretty hard and I struggled with some of the Algebra problems.  I think because the robot looks a little stupid, I had the impression it was going to be easy but I was wrong there!  It's listed as intermediate so it's my own fault for thinking I'm a big-man, but it was cool I managed to complete it as I've learned a fair bit about how microcontrollers can connect to a multitude of different sensors.  It also made me think about taking the EdX Algebra course...