Re: [LAU] Octaver or fuzztone effect

["porl sheean" <porl42@xxxxxxxxx>]

pure data is something i have been wanting to look into. i suppose my reason for the spice thing is that one of my hobbies is building and modifying old valve amps (not a huge success rate at the moment though, but getting there... stupid old power transformers dying on me...). i know that spice will not give an accurate sound of a real valve, but it would be really handy to hear *changes* with circuit modifications on a real signal. things like frequency response are pretty straightforward i suppose, but what about things like sag and the effects of negative feedback? bit harder to judge from the schematic if you are a beginner like me :) i'll have to have a look at your spice thingy when i get home (my machine here isn't set up for stuff like that... yet :).

off topic (from my off topic previous post...): does anyone know where to get *good* spice models for valves/tubes? especially working with oregano (i tried geda but it keeps crashing on me). also good transformer models (i know these can be done somehow with subcircuits, but as i said, i'm still a beginner. i just want some basic 4k/8ohm single ended and push-pull models for basic circuit building.

thanks
porl

On 29/05/07, Robin Gareus <robin@xxxxxxxxxx> wrote:

porl sheean wrote:
>> Hmm. An interesting project might be hacking SPICE into being a
>> kind of a deconvolution engine,
>> to build a WAV impulse response file of a circuit. Then you could
>> use that IR to "play" through the circuit using JACE or similar.

> i have been dreaming of this for so long :) i thought about it the
> other way though, using a 'custom' wave shape as a function generator
> in spice itself. would be very slow this way though.

I've been dreaming about a /jackifiying/ spice ;) - I spiced up my
Pfingst Montag by added a libsndfile voltage-source to ng-spice. - For
simple circuits it's not too far-off real-time performance: it takes
about 4 seconds to simulate 1 second of foxxtone at 48ksps over here.

Now it's Tueday and using a IR seems the way to go... simulating the
foxx effect alone is not trivial. Based on the posted schematics, here's
a preliminary http://mir.dnsalias.com/_media/wiki/foxx.oregano.gz - try
yourself..

> the good news about doing this though is that you don't have to
> (unless you want to) emulate everything about the circuit, just the
> signal path. this would simplify and speed up the calculations
> somewhat.

I've started to document the spice patch at
http://mir.dnsalias.com/wiki/spicesound - the code's barely a few hours
old and highly experimental. NTL, it's already allows to process spice3
netlists reading and generating wav file(s).

robin

PS. pure-data is more fun than this!
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