you must filter the sawtooth wave with a lowpass resonant filter setting a relatively high
Q value, then you have to waveshepe the filtered signal in order to simulate the
distorsion. I suggest to use a smooth table for waveshaping, because the sound quality is
better, for example the central part of a sine wave from which you cut away the first and
the last quarter).
-- 
Gabriel Maldonado

http://www.agora.stm.it/G.Maldonado/home2.htm


the Physicist wrote:
> 
> How can I filter a rectangle/sawtooth so that it sounds
> TB303-ish ? I know the TB305 orc/sco that is around and it
> sounds incredibly good. However I didn't understand it, and
> I want to program a MIDI-controllable instrument like that,
> without this sequencer thing that is in this orc,too. So how
> to do it ?
> I tried filtering a sawtooth/rectangle with butterlp (butterbp).
> The cutoff (center) was modified by the pitchbend value -> It
> didnt't sound like a TB303 at all, and I operated the pitch
> bender on the keyboard like a fool...
>