Hello, I found this project by General Guitar Gadget:
https://generalguitargadgets.com/effects-projects/modulationecho/weslie-modulator/It's a kind of Leslie simulator, it's more a warble effect, but it's pretty unique and new to build.
Here's a demo:
https://www.youtube.com/watch?v=6R4fKmiO_jkIt seems to have a volume drop, maybe a booster after the circuit could be useful.
I tried to draw a veroboard layout (no boost).
That's it, UNVERIFIED.
Tell me if I made some mistake.
I build pedals