This section contains all the information allowing you to build your own Shruthi or hack its firmware.

The Shruthi contains two section: a digital section ("control board" or "digital board"), containing the display, main microcontroller, switches and pots ; and an analog section ("filter board") hosting the VCF, VCA, input mixer and the output stage. Several variants of the filter board are available to provide a broad range of sounds.

Control board

• Schematics, BOM, and assembly instructions for the control board.
• Schematics, BOM, and assembly instructions for the XT control board.
• Firmware.

Filter board

• SMR4 mkII, a solid, Roland-ish, 4-pole filter.
• LP2+Delay, the combination of a MS-20 LPF and a low-fi digital delay.
• 4-Pole Mission, a 4-pole multimode filter inspired by the Oberheim Xpander.
• Dual SVF, the combination of two multimode 2-pole filters - in series or parallel.
• Polivoks filter.
• FX/Digital filter board - a nasty, crunchy, digital LPF/HPF and FX section.
• SMR4 filter board (predecessor of the SMR4 mkII).

Mutable Instruments has stopped publishing any information regarding the use of "vintage" SSM/CEM/IR integrated circuits.

Special editions

To celebrate the launch of new filter boards, limited edition series of kits have been sold.

• Assembly notes for the 4-Pole Mission special edition.
• Assembly notes for the Yellow Magic special edition.
• Filter board assembly for the Midnight special edition (the control board is standard).

Enclosure

• Shruthi XT enclosure assembly instructions .

Here are some files to help you design your own case:

• Export of the Shruthi-1 control board silkscreen, with parts footprints. To be mirrored!
• Blueprint with 3D parts placement by nio101
• A Sketchup export of nio101's 3D model
• SVG file for the acrylic case.
• Image of the Paisley pattern engraved by default on the cases.

Licensing information

Schematics and PCBs of the filter boards ; and documentation/analyses are released under a Creative Commons cc-by-sa license. Firmware code is released under a GPL3.0 License. Some of the (now deprecated) filter boards had been released under a cc-by-nc-sa license.

The authors of the patch library are listed at the end of the manual.