Video: Expanding Your Semi-Modular Synth with Eurorack Modules

These days, there's no shortage of great semi-modular synths: the Moog Mother-32 and DFAM, Arturia MicroBrute and MiniBrute 2, Behringer Neutron, Make Noise 0-Coast, Korg MS-20 Mini, and more.

While the forms may vary, the basic idea is the same: You can play these synths as-is—using only the sounds and processing found within their own chassis—or you can use their included patch points to connect to other synth modules.

Today, we're going to use the Moog Grandmother to demonstrate how you can expand the capabilities of a semi-modular synth with a variety of Eurorack modules.

The Grandmother is great because, unlike some of the other semi-modular synths available, its patch points can be found in place on the Grandmother's own dedicated modules. Oscillator patch points are on top of the oscillator section, filter patch points are above the filter, and so on. This lets you follow the signal path easily, even as you get experimental.

Because most semi-modular synths will already have the basic building blocks of oscillators, filters, and envelopes, we're going to pair the Grandmother with a variety of modules that can add some extra features and character.


While the Grandmother is a traditional subtractive synth—with standard wave shapes like triangle and square—you can use a more exotic voltage-controlled oscillator to start with entirely different sounds.

Mutable Instruments' Plaits offers continuously variable waveforms, formant modulation, and many forms of synthesis—FM, wavetable, and additive—along with a chord generator.

While the Grandmother's built-in Filter section is great, you can also add a creative filter like Intellijel's Polaris—which gives 27 different filter options.


By adding external modulators and sequencers, you'll be able to create dynamic and rhythmic changes beyond the Grandmother's built-in arpeggiator.

Make Noise's Maths is a complex, voltage-controlled envelope that will take control voltages from your semi-modular synth and use linear, logarithmic, or exponential functions to shape, flip, amplify, or to otherwise mangle your sound in any number of musical ways.

Mutable Instruments' Stages is another complex modulator that can be used as a 6-stage envelope, LFO, or 4-step sequencer. The company's Marbles module is a popular unit for creating sets of random yet repeatable noises.

Patchable Effects

What's cool about patching in your effects as opposed to just affecting your synth's output signal is that you'll be able to tweak the effect with the rest of your synth's signal path. (For example, using your envelope's ADSR settings to bring a certain character out of the modular effect it may not otherwise have on its own.)

Here, we're using Strymon Magneto and the Erica/Gamechanger Plasma Drive distortion module. The Adventure Audio Again delay is one of a new breed of effects pedal made with CV patchability in mind.

This is all just a small taste of what's possible when expanding your semi-modular synth with Eurorack modules. Whether you have a Grandmother or a different semi-modular synth, you can find all of these modules and more on Reverb to start exploring new sounds today.

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