As far as I know, there are two wavefolder topologies: series or parallel implementations. The series method is used far more frequently due to its simplicity, as well as the fact that many people are under the impression that parallel wavefolders require specialized rail to rail op amps (as Buchla used them in his priginal implementation). However, that is incorrect. All you need are nonlinear devices that create deadbands that are then summed up.
A youtuber called Krakenpine was able to achieve this with a diode ladder implementation. Each set of diodes in the ladder cut off specific parts of the incoming wave, which is then processed by a pair of clipping diodes to achieve that nonlinearity. The potentiometer at the top attenuates the fundamental frequency, allowing for the folding to be more prevalent. The pot on the left attenuates the input to alter the folding amount.
Check out Krakenpine's channel. He's got a lot of cool synth diy content that I'm definitely learning from!
