28 Oct
2002
28 Oct
'02
1:51 p.m.
On Mon, Oct 28, 2002 at 05:53:26 +0100, Tim Goetze wrote:
That is a side effect of class B amps IIRC. I would have though that
preamps would be class A, but maybe not.
Er, did I? Right. Maybe more sleep would be good ;)
- Steve
make
interesting non-linear filters by using different parameters for the
different halves of the wave cycle. This is what makes the gong sound
gongy (waveguide_nl.h). It could also apply to cone modelling, as the
characteristics of the deflection in the positive and negative directions
will be a bit different.
it's interesting to know that valve preamp stages should have
a small bias (to + iirc), and you can in fact observe this in
the amp output i've recorded. i'm still trying to model the hard-driven valve in
the time
domain. the more i look at it, the more i think the 'building of
potentials' i've tried to describe comes near it. though it would
be nice to base it on hard facts about valve amp behaviour, too.
'building of potentials'? Are you refering to your sinc summation idea?
Its a nice idea, especially as you get anitaliasing for free, but I think
it will be hard to turn a hardish clipping shape into a sum of sincs.
interestingly, the sine, shaped by the hard-driven
amp, looks
a lot like the plots of 'ion conductivity' and 'Aktionspotential'
from human heart analysis.
Woooosh. [that was the sound of that going way over my head ;) ]
Different
amplitudes would be equivalent to how you model nonliear systems
with FIR impulses - I can't believe I didn't think of it before.
in fact you described something along these lines a few days
ago. ;)