Here is a verified layout of Paul Nelson's Cmoxx Tone Machine which is a "cmosified" version of Foxx Tone Machine. Sounds quite synthy and more bassy than the original and the octave up is a bit less pronounced.
And schematic for reference
Note that C14 in the schematic seems to be a typo, bass cap in the tonestack should be 47nF and not 4,7nF.
This thing sounds pretty good