Shruthi 4PM Filter PCB

4PM/Four Pole Mission filter PCB for the Shruthi.  Originally designed by Mutable Instruments, the project was graciously opensourced and is now in continued production from Laurentide Synthworks.

This is a PCB only in a desktop/non-modular format.

Availability: In stock




One board to rule them all… This filter board is probably the most advanced 4-pole core for the Shruthi-system! It uses the same “Pole-mixing” technique introduced in the Oberheim Xpander to provide a cornucopia of filter responses. It also provides 4 different settings controlling the “flavour” of the resonance, clean and liquid, MS-20 style, wobbly/chaotic, and a combination of the MS20 and wobbly modes.

The filter core is based on a SSM2164, for a very low-distortion and pure sound. A LM13700 is used as a global VCA and for resonance control, with loudness compensation.

While this product is in fact a Shruthi-1 originally designed, sold and supported by Mutable Instruments,  it is no longer manufactured by them and therefore is not supported by Mutable Instruments.  Any requests for help troubleshooting issues as they arise during a build that are sent to Mutable Instruments will be ignored.  Please, send any support requests to us, Laurentide Synthworks, or to the SDIY community forums - not to Mutable Instruments.

Although this is not an official Mutable Instruments product, we have been in contact with them during the whole process of continuing the legacy of the Shruthi-1 synthesizer.  All Mutable Instrument's Logos have been removed from all of the products and replaced with our logo.  A disclaimer on every PCB reads "Originally designed by Olivier Gillet for Mutable Instruments, cc-by-sa".  Basically, what this means is this is no longer a supported product of Mutable Instruments, but rather Laurentide SynthWorks.  It carries a Creative Common's license which allows anyone with the PCB files and code to manufacture them, as long as any changes to the design are also shared under the same license.  Although the license does not require the original designers name/logo be removed from the product, we felt it best to adhere to Mutable Instruments wishes regarding this matter.  They want to distance themselves as far as possible from this product and we ask you, the purchaser, to respect their wishes when it comes time to ask for some troubleshooting guidance.


Specs & Downloads

Specs & Downloads

manufacturer Laurentide Synthworks
Depth No
+12V No
-12V No
+5V No
Additional Resources Build Guide


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