16 Aug
2004
16 Aug
'04
10:55 a.m.
On mån, 2004-08-16 at 12:45, Erik de Castro Lopo wrote:
On Mon, 16 Aug 2004 12:13:51 +0200
Alfons Adriaensen <fons.adriaensen(a)alcatel.be> wrote:
Wouldn't the current be limited by the 12k resistor, so that the
impedance of the diode won't drop as fast as you suggest?
Anyways, here is a variation on the same theme, supposedly synthesizing
tape saturation:
http://home3.netcarrier.com/~lxh2/tapesat.html
http://home3.netcarrier.com/~lxh2/tapesat2.gif
/jens
This is a bit too simple. The diode circuit does
not perform hard
clipping when driven at moderate levels.
Something like
out = tanh (in) (or tanhf() if available)
or
out = in / sqrt (1 + in * in)
Both of those would probably sound better than what I posted,
but the original circuit had a 12k source impedance. As soon
as the the input overcomes the forward voltage drop of the
diodes the impedance of the diodes drops to the low hundreds
of ohms. 
If you Spice the given circuit I think you'll find that the
output looks a lot more like what I posted than either of
the above.
Erik