I just found a few germanium transistors OC71...
Is anyone could tell me if a layout exists with this component on it, or if it can be used in one veroboard from this site ?
Many thanks and sorry for my english.
Any layout that uses PNP germanium transistors. Rangemaster, Fuzz Face, Buzzaround, Fulltone Soulbender, MkI or MkII Tone Benders etc etc. The gain and leakage is much more important than the part number, and so that will decide it's suitability for the circuits. I'd suggest trying a few and using sockets for the transistor positions so you don't have to commit the transistors to a circuit you may not like them in (or at least save you risking them by soldering and de-soldering).