Nomnom distortion

[Cotoletta]

Hello,
I have assembled a nomnom phaser on breadboard, everything works fine but I have a major issue: way too much distortion, even without feeding the feedback back to the phasing stages.
If I disconnect the output of the last stage from R20 I have a pretty clean signal, as expected.
If that matters, I'm using a 78L05 instead of the zener diode.
Any thoughts?

[Neffulator]

I have a similar problem with my build.
I've checked the components and connections and everything seems to be alright.
I'm using humbucker pickups and do not own a guitar with single coil pickups, so I can't verify if the signal is just too "hot" for Nom Nom.