BBD delay as simple as possible

[j_flanders]

The way you have your FB and mix set up now, this is what happens:
A repeat goes through the mix pot and arrives at the input of IC2A (the final output opamp)
The same repeat goes through the feedback pot and trough the input of the circuit, it also arrives at the input of IC2A but inverted! because of IC1A.

So, you're mixing/summing two versions of the same repeat, 180° out of phase, at the input of IC2A.
They will pretty much cancel each other out. Because one version is louder than the other it's not a 100% cancellation, but still not a good set up imo.

[thomasha]

Well spotted!

That explains a lot why the wet signal was not as loud! When I adapted the schematic I totally forgot to check the phase. That was dumb!


In this case I need the first stage to be non-inverting or add the feedback later.

Anyway, I tried the original circuit and it sounded better, even with the boost option. Now I'll have to correct that feedback loop.

[ElectricDruid]

I've sometimes swapped Multiple feedback filters in a design for Sallen Key filters (or vice versa) to flip the phase. MFBs are inverting, SKs aren't, if I remember it the right way around. Anyway, it can sometimes help save an op-amp.

T.