I built but haven't boxed them yet, two vintage Maestro fuzzes, the earliest version of the FZ1 (3 Volt version / 3 germanium transistors), introduced in 1962, it's said to be the first fuzztone ever made. I've owned more than 4 of them in the past, and forgot how cool they can be. I did do acouple mods to mine, but can also run it completely stock.
the other one is the MFZ-1 which came about a decade later and is chip based. IMO, it sounds pretty darn good too.
check out this vintage demonstration record of the FZ-1! and if that's not enough, it demonstrates it with a bass!
That demo was awesome. "It's mellow. It's raucous. It's tender. It's raw." "It's completely transistorized." Good stuff. It sounded good too. What kind of changes did you make to yours?