The second module in the Erica Synths and Moritz Klein educational DIY collaboration is a Dual VCA following on from last months VCO.
EDU DIY VCA
This is a brilliant series of modules designed to help you learn about the circuit, design and function of the Eurorack based building blocks of synthesizers. Last month saw them take on the complexities of the analogue oscillator. This month it’s a bit simpler with the Dual VCA where you only have level and offset to worry about. But don’t be deceived, there’s a lot going on behind the scenes and this will give you the opportunity to learn about the most important of all functions within a synth – the ability to change the level of a signal.
A VCA isn’t just a signal amplifier, it’s used to affect change on any signal, audio or CV whether for sound or modulation or the modulation of the modulators that modulate sound. And it can do it manually with a knob or via control voltage from another source.
The Dual VCA is DC coupled so it can handle CV and audio. You can use the two separately or together from a single input to come up with two different outputs.
The module comes with a 60-page manual and build guide that’s designed to take you through, not only the build of the module but working out how it works on a breadboard. One addition Moritz has made to the manual are links to an online circuit emulator called CircuitJS. This gives you a brilliantly animated example of the circuit we’re looking at.
It’s a wonderful approach and a fascinating journey to go on. I intend to tackle the whole series as they come along in a number of live streams where we can experiment, learn and build the module together. The VCO was an intense learning experience that ended up being split across a number of live streams but it was thoroughly engrossing, I’ve linked to the first build video below. Hopefully, the VCA will be a bit simpler and smoother as we’ve all got the hang of how the process works. Moritz has also been able to tweak the documentation in light of feedback from the first module.
This is going to turn into an amazing series of modules and there are 9 in total to make plus a small case and DIY PSU. The plan is to release a new one every 4-6 weeks. I’m planning to do my live stream build of the VCA in about a week so if you want to build along then you should get your order in.