Shruthi SMR tuning

This discussion was created from comments split from: Again on VCF tuning on SMR.

Hi all,
I have a similar problem in my smr-4 mkII (v0.3). Cutoff only works when the knob is hereinbelow of 20, and if the above then I did not hear any results .In any case, exceed the range of the cutoff operation a little more than 10 out of 127. I tried to calibrate it using the V/Oct pot but it is only slightly shifts the cutoff point. I have no idea how to fix it because at MI have not found a lot of materials relating to the calibration of the SMR filter version (v0.3)
Does anyone know what I did wrong?

Could you post a photo of your board? Looks like an assembly mistake to me…

Sure. Is that photo is meaningful?

Oh my god, please tell us who sold you this or how you ended up with this board.



Together with a few friends last year I ordered a set of preprogrammed chips and cases
from MI. Components and other parts I ordered from Farnell, the Mauser. I downloaded the materials on the pcb board from MI github and i printed in the company that performing the pcb board in my town. As it turned out, it’s better if I ordered complete kit directly from MI shop because now I have problems with this filter

The board you have here is the 3rd revision of a single-supply, 12V powered version of the SMR4 mkII circuit (SMR4-mkII-12V). It stayed at the (probably not-working) prototype stage and was abandoned more than 3.5 years ago. It has never been documented anywhere, and has never been produced in more than 3 prototype units.

So in this version, it will not sound correct? Too bad, maybe even a few IC’s will be useful to another project.

Frankly, I don’t remember. There was a noise issue due to the single-supply design, and there might have been incorrect component values silkscreened on the PCB.