Here is a Delphi/Object Pascal translation of Antti's Moog Filter.
"At last DAFX I published a paper presenting a non-linear model of the Moog ladder. For
that, see http://dafx04.na.infn.it/WebProc/Proc/P_061.pdf
I used quite different approach in that one. A half-sample delay ([0.5 0.5] FIR filter
basically) is inserted in the feedback loop. The remaining tuning and resonance error are
corrected with polynomials. This approach depends on using at least 2X oversampling - the
response after nyquist/2 is abysmal but that's taken care of by the oversampling.
Victor Lazzarini has implemented my model in CSound:
In summary: You can use various methods, but you will need some numerically derived
correction to realize exact tuning and resonance control. If you can afford 2X
oversampling, use Victor's CSound code - the tuning has been tested to be very close
Ps. Remember to use real oversampling instead of the "double sampling" the CSound code
I did not implemented real oversampling, but i inserted additional noise, which simulates
the resistance noise and also avoids denormal problems...