The Octavia is one of the many legendary effects to come out of the late 60s. It is also one of the rarest pedals of the era, as there weren't many built. Like most effects of its day, the Octavia is a positive ground effect. There are several schematics for it floating around, but the one I based this layout on can be found here. Most positive ground effects I layout I also post a negative ground effect version as well. I haven't done so for this one to keep the classic mojo of the original. If you want to make it negative ground, just rotate electrolytic caps, the 1N4001 polarity protection diode, and use NPN transistors for Q2 and 3.