Creating a tiny Eurorack system for controlling and processing external hardware synthesizers

Alex Anderson

Eurorack is an exciting and enticing concept for many but the complexity and expensive cost of entry can be enough to turn many potential users away. There is also lots of confusion between what you can and can't do. Our advice to anyone trying to get into eurorack is see how it could fit into your existing setup, and just go for it!

Last week, I came upon an Arturia Microbrute and Drumbrute super cheap at a local synth swap. These little devices work really well together and are a great place to start with synths/drum machines. They're CV compatibility made me instantly want to make this system and in turn, this blog post and accompanying video.

One of my friends in the local synth community is interested in putting together a small eurorack system for processing his 303 acid boxes.  The dude loves acid music and is obsessed with the 303 909 combo.  I decided to make a little post and video inspired by him using the two new pieces of gear I had acquired.  

Using a bare bones set up I put together something that was a blast to play with and that had a bunch of options for interaction.  Had I spent more time, I probably could have made a bunch of videos with this set up, changing the routing and what controls what, but I had a blast doing what I did.

I learned that you don't need anything crazy to have some fun.  I scrounged two adapters to get the 1/8th inch signal into the interface and just used the headphone outputs of the MB and DB to get audio into the modular.  I didn't need any extra gain as the devices provided plenty, and no attenuation on my outs as the interface handled the signal beautifully.   The weird thing is that in the video, it looks like my volume is really low, but that's because I wasn't using the master output.  In fact, my HP out level was almost maxed as I liked the sound of the TRSHMSTR more when it was driven with a hot signal.

In this video, I created a small eurorack system made for processing external gear using the Doepfer Beauty case, the Shakmat Knight's Gallop, a WMD Aperture, and WMD Aperture.

I am clocking the Shakmat Knight's Gallop with the Clock out on the DrumBrute and then using the KG to create the triggers for the sequencer on the Microbrute. This way I can create interesting rhythmic sequences with only programming a few notes and change up the rhythm easily with the turn of a knob.

The Microbrute and Drumbrute are running into the TRSHMSTR and Aperture respectively (via their headphone outs!) and eventually I control the filter frequencies of each module with the CV outs on the Microbrute's patchbay. Though the Drumbrute has a built in filter, you cannot control it dynamically with the LFO or with CV. Also, the Aperture has a character that I love on drums due to it's variable bandwidth and feedback control.

The TRSHMSTR crushes the bass line and with a little help from the Microbrute's envelope CV output, it gets a nice and gnarly squelch pretty quick. Both of the modules are running directly into my audio interface via 1/8" to 1/4" adapters and 1/4" cables. This is fine to do as long as you aren't clipping the input of your interface or mixer. If you are having clipping issued due to high volume, add an attenuator.

If you have hardware synths that you love, are thinking about getting into eurorack but don't know where to start, try some processing! It's super fun and relatively easy to understand. Also, processing let's you start making music immediately with what you already have, which we here at WMD believe is the most important part. Make music and have fun doing it!

No talking in this video, just tunage and some complimentary text spelling out what happens as it happens.

For more information on Aperture:
For more information on TRSHMSTR:

Intro music is the Sequential Circuits TOM running through a Geiger Counter PRO.  Full video of that coming soon ;)

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