I suspected that they were as well (and this is the first time I've seen that video) but my findings were a little different from his. It could be that we had different revisions of the pedal. I've seen this pic, this is
not the version I have... Also there were no missing or jumped diodes.
There is an audible difference between them,
especially on a clean tone, and I'm not a metal guy. The 33 has a bit more of that upper midrange almost "cocked wah" thing going on. The Grind is a bit more open sounding
Component-wise the difference is minimal and either circuit could be built on the same PCB no problem.... Rather than have more than one PCB, I decided to combine both circuits
and the Integral Preamp into one switchable PCB. Any one of the three circuits can be built independently as well (if desired) by omitting a few components.