Explain "built in speaker simulation" in pedals

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eagertokill
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Post by eagertokill »

Hey everyone. Can someone explain the circuit details for pedals with built in speaker simulation/emulation. A lot of makers are including 2 outs, one for the normal pedal chain and one line out for direct to pa or direct recording. They say speaker simulation or emulation and generally they sound good. AMT pedals(huge fan here) does it as well as a few others.

How does that circuit work? What exactly does it do? And, how difficult it it to adapt that feature to another pedal?

I have a AMT Freak Guitar twin tube pedal that sounds great direct into a P.A. and I was just curious. Thanks!!

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ech0es
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Post by ech0es »

An example:
Image

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eagertokill
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Post by eagertokill »

Can this^^^^^ be added to any pedal? Any more info on how the circuit works?

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Post by RnFR »

joe davisson mad a simple cab sim that would be easy to attach the end of a circuit. it basically smooths out the high end.
here's a link-
https://www.diystompboxes.com/analogalc ... lesim.html
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Post by analogguru »

Does there exist more info on the speaker-sim in the posted schematic ?
It looks a bit odd.... especially around C8...

analogguru
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Post by Silent Fly »

ech0es wrote:[...]
Blind test!
[...]
WHere is the simulation, where is the real V30 ? :scratch: :hmmm: :?:
1 = sim
2 = real

...or maybe the other way around :scratch:
"Remember - all I am offering is the truth, nothing more". Morpheus

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Post by ech0es »

analogguru wrote:Does there exist more info on the speaker-sim in the posted schematic ?
It looks a bit odd.... especially around C8...

analogguru
On the schematic it's wrote: ProjetG5

So on the website projetg5 you can find this:
http://www.projetg5.com/modules.php?nam ... tit&lid=60

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Post by analogguru »

Thanks..... didn´t think that ProjectG5 could have a .com-homepage.

That package looks better now. The originally posted above schematic is wrong.

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Post by ech0es »

analogguru wrote:Thanks..... didn´t think that ProjectG5 could have a .com-homepage.

That package looks better now. The originally posted above schematic is wrong.

analogguru
so, could you correct it ? what is wrong ?

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Post by eagertokill »

Thanks for the info! Question, can that circuit be added to any od/distortion box? Or any box for that matter?

Also, in the sim, which one was the real and the sim? I think I know but I'm not sure.

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Post by ech0es »

Silent Fly wrote:
ech0es wrote:[...]
1 = sim
2 = real

...or maybe the other way around :scratch:

clean 1 & crunch 2 real V30

clean 2 & crunch1 simulation

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Post by analogguru »

ech0es wrote:
analogguru wrote:Thanks..... didn´t think that ProjectG5 could have a .com-homepage.

That package looks better now. The originally posted above schematic is wrong.

analogguru
so, could you correct it ? what is wrong ?
Below is the corrected schematic.

analogguru
Attachments
v30simjl2_edit.gif
v30simjl2_edit.gif (8.5 KiB) Viewed 5087 times
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Post by BJF »

Hi,

That looks similar to a H&K Red box.............good sounding unit btw

Speakers form a complex filter and the most prominent effect is lowpass filtering, but that alone is not enough to make something similar to a guitar speaker response but some guitar frequencies need to be highlighted.

Just talk a look at your favourite speaker and you'd find the 'presence' peak at what any recording engineer with some experience with recording electric guitar would call 'guitar' frequencies- that's the ones that you push just a little bit to forward a guitar in the mix............

Ahum but explaining why such filters would be in guitar pedals.......holy Jaggernaught are we talking direct connection to PA? Something you can possibly do with a keyboard and only so and so with bassguitar........ :horsey:

Ahum, now phase response.......to design for nonlinear distorted guitarsounds.....Bessel would be interesting............how about defing the upper frequency point of what would be considered intelligable treble?

Just as a rough measure 5 to 7 Khz likely above 7 Khz there's not much that cannot be dampened and for correct phase uneven poles would be best so constructing not a brickwall but suitable might include a 5th order partly Bessel maybe partly Chebbychew and could easily emply the Sallen and Key type filters.YEs yes there would be building blocks that could do the job, right?

Circuits and dimensioning can be found for instance in Audio IC OP amp Cookbook and related literatur on filters..........

However never forget the 'presence'peak- a 3dB filter will do just fine ;)

Ah have fun gent's
BJ

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Post by Silent Fly »

ech0es wrote:
Silent Fly wrote:
ech0es wrote:[...]
1 = sim
2 = real

...or maybe the other way around :scratch:

clean 1 & crunch 2 real V30

clean 2 & crunch1 simulation
I listen only the crunch :oops:

What let me think that crunch 1 is a simulation is that simulations sometimes let part of the higher frequencies go through. Crunch 1 is slightly brighter and less midrange-rich.

I guess it is why the BAJA Active Harmonic Converger make sense :)
"Remember - all I am offering is the truth, nothing more". Morpheus

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Post by ech0es »

somebody can trace a layout for the corrected version of the V30 sim ?

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Post by Mr. G. »

I thought the sim sounded really good myself. It might could use a bit more high end attenuations, but it still sounds better than a lot of the other ones I've heard. I would also be very interested in a layout for this.

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Post by RnFR »

there is a layout above, but it is set up to run off 230v mains to a 22v supply. would an 18v supply off a charge pump suffice?
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Post by DeanM »

RnFR wrote:there is a layout above, but it is set up to run off 230v mains to a 22v supply. would an 18v supply off a charge pump suffice?
Its actually +/- 22V. and on the schematic and layout that feeds a 7815 and a 7915 regulators so it runs off +/-15V. So i dont think an 18V supply would work on its own. maybe a mix between a charge pump like you say and a split rail supply. e.g. 9v > 18V. 18V > +/-18V.

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Post by JakeAC5253 »

Not sure what all is going on inside that huge chip, but from the looks of it it seems to be HP/LP filters with a slight upper treble boost. Can't really see much else. A passive EQ.

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