Mullard OC81 - Now thats a vintage Transistor Mullard OC81, building a custom for someone. But shhhh OC75 standard sound better, more ballsy ! I just find the OC81 just not as hot as OC75s, also they seem to waver all over the place in strength and noise. SUPER expensive, OC75s are bad enough, but these are almost $20 a piece, you need 3 for the Zoso. I would just stay standard and rock the world with overflowing beautiful fuzz pedals !