Eurorack DIY Benjolin, PCB from Tseng Kweiwen

Some modifications based on Rob Hordijk's design:

an external audio input to filter
the pitch is voltage controllable in both oscillator
the frequency of low pass filter is voltage controllable
disconnect t2 to filter (you can still use cable to connect t2 to filter's CV input)
add a spst to switch the current input(p1 or -9~9v voltage with a potentiometer) to bc547

https://www.muffwiggler.com/forum/viewtopic.php?t=165775