Hi
Can I use a pnp trans on a npn circuit by just twist the leads?
I find on the web a fuzz circuit that uses bc108 and I have a bunch of AC128 that are pnp
Can I use them?
No you can't.
You could probably convert the circuit to positive ground so you can use the PNP transistors, but If it was me I would just get some NPN transistors, and use the PNP's for other projects.