[sdiy] [OT] Tube Screamer in depth modelling

[Leonardo Laguna Ruiz]

Hi Andy,

this topic is very interesting for me. I work developing simulators and 
many years back I developed a (not so good sounding) model of the MT-2 
pedal. I wonder what kind of methods you used to make it. Did you used a 
SPICE-like approach or an ODE/DAE solver?

Leonardo

On 05/23/2017 09:18 AM, Andrew Simper wrote:
> Hi Guys,
>
> I know this is a little off topic since strictly speaking it's not a
> synth that is being modelled, but I know lots of people on this list
> do various DSP analog modelling from time to time, and use SPICE (etc)
> to model stuff.
>
> I'm just finishing off a VST/AU/AAX plugin that is a full discrete
> component model, and modified Boyle op-macro model, of an Ibanez Tube
> Screamer TS-808. One of the interesting things is that when I was
> matching the various resistor / capacitor / diode model parameters I
> added a list view of every "constant" to the model so I could more
> easily edit them and fine tune the model to match the units I have
> used as a reference. I found this to be quite a lot of fun, so I
> decided (possibly to my peril) to allow everyone access to this list.
>
> I added a few extra resistors and capacitors to the model so that you
> can also model all the modes on a TS9DX, and also the Boss SD-1. You
> can alter the op-amp's slew rate, unity bandwidth, and dc open loop
> gain, and swap different diodes and roughly change how many diodes are
> in series in the main clipping section. I also added a battery voltage
> pot and series resistor, and pot to adjust the bias. You can also add
> your own diode .model statements to add them to the dropdown list of
> available diodes. Supported diode model parameters are: IS, N, ISR,
> NR, RS, CP, TT, CJ0, VJ, FC, M, IMAX, anything else will be ignored.
>
> It's loads of fun to play with, especially on synths, here are some
> audio examples of distorting a 303. First is the riff through an
> actual TS808, then through the plugin, then through a "modded" version
> with op-amp slew and and different caps to distort more of the signal:
>
> www.cytomic.com/files/scream-acidvoice-saw02-ts808.mp3
> www.cytomic.com/files/scream-acidvoice-saw02-scream.mp3
> www.cytomic.com/files/scream-acidvoice-saw02-scream-mod.mp3
>
> If any of the usual suspects here at synth-diy want a free copy I
> would love to give you one, just email me directly with your name and
> email in the form (I'm lazy and this makes it easy for me to copy and
> paste to assign the free copy to you):
>
> Firstname Lastname <your at email.address.com>
>
> I've learnt so much from this list, and really appreciate everyone's
> time and effort in their posts on such a wonderful variety of topics,
> it's not much of a thank you, and it's partly me being proud and
> wanting to show off all my hard work, but it is a pretty cool little
> plugin and hopefully some of you may find it useful for your music.
>
> If anyone wants to know about some of the details of the modelling
> then please ask away, I'm open to chat about anything.
>
> Cheers,
>
> Andy
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