I know it’s a bit late, but the most recent layout’s threshold switch wiring is incorrect. Threshold 3 should connect to the other side of the 13k. It’s actually easier to just remove the 13k and 47k altogether and wire a 50k pot with lugs 1/2 connected to threshold 2 and connect threshold 3 one row...

BBD Flangers tend to have clock trimmer that needs to be set verrrry carefully, and there is also usually a trimmer to adjust feedback of the resonance. Instead of replacing things, try moving the trimmers around. Technically you need an oscilloscope for the clock, but I’ve done it by ear plenty and...