The world is a complicated place.
And sometimes adjusting knobs just makes everything more complicated.
This is why you might want to use this PCB to build yourself a clone of the Tentacle by Earthquaker Devices wich is pretty much a slightly reworked version of the Green Ringer by Dan Armstrong.
No knobs!
Unlimited octavey fun!
And if you want to make things more complicated I have added pads so you can add effects in front of or after the octave while still keeping the PCB switch-mount.
You can also get this as a kit from Musiking here