[linux-audio-dev] spiced 12AX7, plots, clipper.so

[Tim Goetze]

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