Ambika Hybrid Polyphonic Synthesizer

Type: Hybrid Analog Subtractive, Digital Wave Table

6 Voice Cards, each with:

  • Oscillators: 2
  • Envelopes: 3
  • Filters:  24dB Slope (4-pole), Band Pass, High Pass, Low Pass, Resonance
  • LFO: 4
  • Polyphony: 6
  • Timbrality: 6
  • Modes: Polyphonic, Split, Unison
  • Patches RAM: Limited To Storage
  • Storage: Internal, SD Card
  • Editing: USB
  • Arpeggiator
  • Sequencer
  • Designed by Olivier Gillet and Mutable Instruments:
  • Open Source Hardware & Software


Mutable Instruments produces some of the greatest components for the Eurorack modular synthesizer crowd. Almost all of them are open source hardware and software. They thrive off sharing their products with the tinkers and hackers in the world, because it leads to better products and new ideas. One of their first projects was the Shruthi a monophonic design that uses a digital control board and a analog voice card. Various different voice card designs allow the user to swap them out, and get a totally different sound. Consider then, the Ambika which is like a kicked up Shruthi only add 6 independent voice cards to enable 6 voices of polyphony or 6 independent synths altogether.

If your confused here, jump back to the PreenFM2, and read the explanation of timbrality and polyphony. Also like the PreenFM, the Ambika is completely open source which means you can download the Firmware, source code, instructions and cad files to get a laser cut case made of any material you like. Get the files from GitHub here.

There is also different types or designs of voice cards. The two in the header image have different voice cards, the solid black unit uses the SMR4 voice card design while the red coloured unit has 6 4-Pole deigns. In both cases I had the PCBs made, but like the PreenFM, you can order these prebuilt or you can order PCBs from various 3rd party sources.

Here is the SMR4 voice cards and all of the components needed to populate the cards. The digital wave tables and oscillator is form the processor (MCU) IC on each card. Regardless of filter design, all voice cards will use the same firmware and digital circuit built from an Atmel ATMEGA328P processor.

You can load the firmware directly onto the voice card once powered up, but I had yet to build the main control card (which supplies power to all the voice cards) so I flashed each processor using one of my breadboard circuits.

The control card uses an Atmel ATMega644 processor, and I flashed it after preliminary power tests where completed. Once that is done, you simply set jumpers on the voice cards and then stack them up.

How does it sound?

This is an amazing synth! Truly outstanding and I would put it as comparable to any 6 voice Roland or Dave Smith synth, especially with this price. You can build one of these for just under $350 if you source all of the components yourself.