[LAD] simulating analog audio devices

[Tim Goetze]

[Erik de Castro Lopo]
>The problems you get when doing a discrete time simulation of non-linear
>processes are mitigated as the sample rate is increased. Therefore, the
>higher the sample rate the better.

For guitar distortion, I've found that at 4x oversampling the quality 
starts to sound bearable, and 8x is what the CAPS units use (with an 
up- and downsampler FIR filter of 64 taps each).

When I started working on virtual amps, this page helped a lot:

http://web.archive.org/web/20051128104636/http://www.eecs.umich.edu/~mmccorq/tubes/simulation/simulation.html

It contains a fairly detailed 12ax7 model (the best I found on the net 
at that time), in a roughly drafted preamp netlist:

http://web.archive.org/web/20050905045956/www.eecs.umich.edu/~mmccorq/tubes/simulation/preamplifier.sp

My own interest in re-running spice simulations of such circuits is 
pretty limited (sorry Robin!) but perhaps you may find this 
interesting.

Cheers, Tim