after taking some plots from a simple 12AX7 preamp spice model, i've decided to try naive asymmetric hard-clipping, without any antialiasing measures.
http://quitte.de/12AX7-clipping.html has the plots, a link to the spice model source, the hard clipper ladspa implementation and the mandatory mp3: http://quitte.de/brat.mp3 which is the output from this signal chain: guitar (bridge pickup, humbucker) -> HiPass (200) -> Gain (db = 30) -> clipper.so -> unmatched.so it may not be a true amp model, but to me ... it rocks. i'm still pondering whether antialiasing is needed, and if so, how to do it (fit in a windowed sinc where the signal hits the clipping threshold? thoughts welcome). for building a decent 'virtual amp', i imagine some combination of Steve's excellent valve and valve_rect for a good, smooth and warm lowish-gain tone, a bit of tunable eq and this kind of hard-clipping for hi-gain, harsh distortion topped off with a cabinet response will just about do it for me. tim
