The Shruthi-1 DIY Digital/Analog Monosynth

The Mutable Instruments Shruthi-1 is a hybrid digital/analog monosynth sold as a DIY kit for €130.00.

The kit includes everything needed for building the Shruthi-1 synth, except for the enclosure:

  • PCB for the digital section and the filter
  • All electronic parts / ICs
  • Pre-prgrammed ATMega644 and patches/sequences storage EEPROM
  • Switches caps / knobs
  • Blue backlight LCD display
  • Connectors
  • A pack of screws / spacers / nuts for holding the two boards together

The Shruthi-1 design is simple, but offers a unique voice, ranging from “grungily digital” to “weird and warm”. It’s also open and designed to be hackable. 

The developer describes it as a “best of both worlds” design:


An 8-bit microcontroller plays the role of the two main oscillators + sub-oscillator. This allows the generation of (aliasing-free) classic analog waveforms, but also wavetable/transwave synthesis and a trove of weird digital algorithms (sinewave bitcrushing, formant synthesis, phase distortion, bit toggling, XOR modulation).

… and Analog

Beyond this point, everything is analog. Most of the Shruthi-1s are built with the SMR-4 filter, a warm 4-poles “modern analogue” low-pass (no vintage IC). But you are in no way limited to this! The filter section of the Shruthi is on its own board and can be easily replaced. We currently offer 2 alternatives filter boards, one with the CEM3379 VCF/VCA chip of the Ensoniq/Waldorf fame ; and one with the classic SSM2044 VCF. More to come, based on vintage chips or modern OTAs and VCAs! From silky-smooth to squelchy or fat: pick the filter that matches your personal taste best.

The Shruthi-1 has an audio input: external signals can be processed by its analog section, under the control of the digital LFOs, sequencer and arpeggiator for crazy gating and re-enveloping effects. A perfect way of warming up the sound of your favorite VA or… cheesy organ!

Details on the Shruthi-1 are available at the Mutable Instruments site.

Demo video by Michael Kathke.

4 thoughts on “The Shruthi-1 DIY Digital/Analog Monosynth

  1. Hi,

    Okay, this IS about the coolest stream of sounds I’ve heared in a LONG time!
    Is that track available for download????

    This type of music is why I got into electronic music!!

    Well done!


  2. My favorite part about this synth is that it has such a unique voice that is both modern and 80s/90s retro (is that retro yet? nostalgic, perhaps?). The fact that it's cheap as hell and is open to modification makes this a no-brainer to any synth DIYer. Plus it's so usable, and the amount of sounds you can get out of it is unreal.

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