[LAD] simulating analog audio devices part II

[porl sheean]

hi Giuseppe

would it be at all possible to provide a link to the ltspice file you made
of the amp? i am having trouble finding out how to do things like output
transformers well, and didn't even imagine the possibility of spice
simulating a particular speaker. whilst i am eagerly watching the ngspice
patchset i would like to play around with one that i know works so that i
can make sure i'm doing things right.

ps. where abouts did you get the models for the transformers, valves and
speaker from? and how did you simulate the reverb section?

cheers
porl

On 08/06/07, Giuseppe Zompatori <siliconjoe at gmail.com> wrote:
>
> Hi,
>
> Some time ago I did a sim using LTSpice
> (http://www.linear.com/designtools/software/) under Wine of a Carvin
> Legacy tube amp. LTSpice was the only program that had wav in/out and
> would run on Linux at the time I tried this.
> The schematic for the amp is here
> (http://carvinmuseum.com/pdf/amps/VL100%20&%20VL212%20Legacy%20Amp.pdf).
> It's a complex beast that ngspice would have lots of troubles
> simulating because of the infamous "floating nodes" and other quirks.
> Everything is included into the sim, preamp, phase splitter, output
> valves , output transformer and even the model of a greenback speaker.
> Naively, I haven't set the sim time step to the a sampling freq
> related number, nevertheless it sounds Ok to me, I dont know how
> LTSpice deals with transient sims involving wav files in details.
>
> The ogg for the sim is here:
>
> http://siliconjoe.googlepages.com/legacy-swcadiii-1-cab-reverb-delay.ogg
>
> I played a bounch of fast licks to have the transient sim finish
> before the universe will collapse, yeah you guessed it it's pretty
> slow... I think it took 1 day to finish on an AthlonXP 2800+...
> Now days I am messing around with GNUCap and QUCS (http://qucs.sf.net)
> to which I just ported my first tube model whose plate voltage/grid
> current curves look like that:
>
> http://siliconjoe.googlepages.com/Schermata.png
>
> Hopefully a way to inject wav files in both GNUCap and QUCS will come
> true as they both seem better than spice derived programs.
>
> Cheers,
>
> -Giuseppe
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>
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