Shruthi with polivoks filter : MIDI BUT NO SOUND

Hey there could anyone help me with this situation :

Assembled the shruthi with the polivoks filter, it receives midi info and everything seems to be working well but i can’t get any sound out of it even as just a filter with in and out …

Candy offered to any one who can help
thanks a lot

Have you fitted both stacking connectors?
Have you checked your soldering in general?
Are all chips at the right position?

Is the “pvk” filter option selected in the system settings?