Some time ago when I was looking at different chips for ring modulators (such as AD633) I came across these weird log amps. I ended up getting one of AD8307, which is “LOW COST” (=18€ for one chip on Mouser!), just like AD633 (wasn’t this one too “only” 6€ few months ago? Now it’s 18€ lol).
I did some simulations on LTSpice (with the similar AD8310 chip) to figure out what I could do with the chip and ended up with this hacky schematic:
The chip output stays quite constant while changing input amplitude,
Varying the internal input biasing/gain network allows interesting nonsymmetries,
Just like with other distortion circuits, filter seems to be quite useful addition. Active filter is needed to prevent the gain loss.
Hopefully I have time to try to build this this summer 
This will most likely become a guitar pedal as synth levels seem to be too high to work nicely.
