These are sets of 6 filter boards for the Xena desktop synth. They are preflashed with stock firmware and NOT calibrated.
SMR Filter: This filter uses the same topology as the Shruthi SMR4mkII. It is a low pass 4 pole OTA-C filter. Its a smooth "Rolandish" type filter
4P Filter: This filter uses the same core as the Shruhti 4-Pole Mission but only offers the LP4 output. I would characterize the 4P filter as a a bit fuzzier than the SMR type
SVF Filter: This filter board features a 2-pole state variable filter with low-pass, band-pass and high-pass modes. It is half of the Shruthi SVF Filter
Original CAD file, PCB & Schematic and original design elements provided by Mutable Instruments under creative commons CC-BY-SA-3.0 license.