JP6 All-pass tested

I've breadboarded and tested the AP-filter from my all-pass simulation, version AP-C: https://atosynth.blogspot.com/2023/04/jp6-filter-allpass.html

It only required minor tweaks.

During testing, my BP outputs +/-3.5V and the HP/LP outputs +/-5.2V. I assume that BP is affected the same way HP/LP is by the resonance feedback, so adjusting feedback so that HP/LP are normally +/-5V probably also affects BP amplitude.

Anyway, to get AP we need to mix 2x BP with the inverted input. But the BP needs to be unity gain.

If we assume that unity gain is +/-5V when properly adjusted, it is 5.2 when HP/LP is 5.2. That means that to bring it up from 3.5V to 5.2V we need a gain of 1.48. The simulated circuit has a gain of 1.33 when using a 100k/33k combination. Replacing the 100k with 68k gives us the gain of 1.48 that we want. 

Here is a video of turning the cutoff CV knob, see how the phase changes.

The resulting circuit is like this:

PS: We need to sum everything BEFORE it reaches the filter as we need input both for AP and normal input. But this affects the polarity of the input and probably also the feedback circuit.

PPS: I am not sure how we can use AP/Phasing. Do we need to be able to pan wet/dry to different channels? Should this be an option anyway for filter outputs?

Update: Here is an alternative circuit, the AP output phase is 180 degrees different from the one above but it saves one op amp that can be used to sum stuff before the filter