Here is an old odd cat. This is an all discrete clean monophonic octave down effect made by Shin Ei back in the early 70s. Initially I though this was a Maestro OB-1 clone but the schematics revealed that's not the case.
See the notes below the layout for components that needs matching for best result. And I must admit the switching is a bit confusing but I think I got it right. Also worth mentiong is that reducing the horizontal cap right to Q11 will give a more aggressive and louder octave down signal.
It was sold under several brand names like Pax, Rands and Sekova. Colorsound also made their own version called Octivider but it had a quite few value changes so that one deserves an own post.
*Update 240120* Verified by JRuss with a small correction. Pinout of Q77 altered to match the schematic.
