Speaker Saturation Simulator

[stm]

I posted this on another thread that seems to be dying, and I wanted to give this more visibility, so I am posting it here with some additional info:

Some months ago I was looking for an equalizer and some circuit to add more brightness to my guitar for clean playing.  I also wanted to have a very mild overdrive, just for warmth, which my cloned SD-1 couldn't give, because IMO it sounds crappy at low drive settings.  (Before anyone points me to Professor Tweed or Peppermill, I have to say at that time didn't know of ROG   )

So I implemented a two band Eq plus a variant of an Analog Tape Saturation emulator circuit.  The results were very interesting.  The modified tape saturation, which I finally called "Speaker Saturation Simulator" added that extra brightness I was looking for in such a way that it was better than just using the HIGH control of the EQ.

The circuit is posted below, and contains a link to the original schematic that inspired me.



The SSS just simulates the magnetic saturation.  The other phnomena associated with speaker "breakup" such as resonances of the cone due to deformation when overdriven are not dealt with.

I think this is an interesting circuit to go after any ROG amp simulator, provided you are not playing at a level where the speaker is actually in breakup (i.e. in my apartment), otherwise the sound may be overprocessed.

Have fun!

[aron]

Hey,

Great idea. Yes, usually the speaker breakup is the missing ingredient. Can you make a sound sample?

[Steben]

Some "sunshine of your love" samples maybe...?
:wink:

[Ge_Whiz]

Nice idea, but I don't entirely see the point of stacking up all those germanium diodes? :?

[stm]

As for the sound samples, I would need to learn "Sunshine of your love" first  :wink: I'll see if I can mount something on my PC to record a sample.

Regarding the stacked Ge diodes:

The 1N4148 has a nominal threshold voltage of 0.6V.  In a similar manner, the Ge's have a nominal threshold of 0.2V. Also, they have higher DC resistance and a softer knee than Silicon.  Having them in series is like having a softer knee diode with an overall threshold of roughly 0.8V.  In other words, this arrangement produces much softer clipping than two Silicons in series.  Also, something to try for even more softness is reduce the SATURATION pot from 10k to 2k or even 1k.  The lower it is, the softer the clipping due to the fact that the Ge diode's internal resistance will be more significant.  Gotta try this.

Thanks for your comments.

[jayp5150]

----------------------------------------------------
----------------------------------------------------
---------------------------------------10-------------
----------------------------------12-------12----------
--12-12-10--12--12--11-10----------------------
--10-10-8---10-----------------------------------

[Elektrojänis]

----------------------------------------------------
----------------------------------------------------
---------------------------------------10-------------
----------------------------------12-------12----------
--12-12-10--12--12--11-10----------------------
--10-10-8---10-----------------------------------

This is a bit offtopic but i think there is a one extra note in those powerchords . It does not come through clearly behind that dark tone but I think it really affects them tonally (makes it sound a bit more evil.

Try:

---------------
----------------
--11-11-9--11
----------------
--12-12-10-12
--10-10-8--10

..or something...

[Ansil]

[quote="Elektrojänismakes it sound a bit more evil.

Try:

---------------
----------------
--11-11-9--11
----------------
--12-12-10-12
--10-10-8--10

..or something...[/quote]


i also play it this way.  but i just find wherever i am on the neck and go for it.  usually i like to play bass on this song and let my bass player go wild.

[Steben]

---------------------------------------------------
---------------------------------------------------
--11-11-9--11------------------------10^^^---
--12-12-10-12-------------------12-----------12
--12-12-10-12----12-11-10---(12)-------------
---------------------------------------------------

I used to play it like this some times

[Peter Snowberg]

I always played it like this: (roughly)

Code Select Expand

---------------------------------5--5--5---8--8---3--3---5--
--7--7--5--7---------------6-----5--5--5---8--8---3--3---5--
--7--7--5--7------------7-----7--6--6--6---9--9---4--4---6--
--7--7--5--7---7--6--5-----------7--7--7---10-10--5--5---7--
---------------------------------7--7--7---10-10--5--5---7--
---------------------------------5--5--5---8--8---3--3---5--

Cool circuit STM. Thanks for posting it!.


As tiny purple fishes... run laughing... through your fingers... and you want to take her with you... to the hardland... of the winter.....

[Steben]

I always played it like this: (roughly)

Code Select Expand

---------------------------------5--5--5---8--8---3--3---5--
--7--7--5--7---------------6-----5--5--5---8--8---3--3---5--
--7--7--5--7------------7-----7--6--6--6---9--9---4--4---6--
--7--7--5--7---7--6--5-----------7--7--7---10-10--5--5---7--
---------------------------------7--7--7---10-10--5--5---7--
---------------------------------5--5--5---8--8---3--3---5--

Cool circuit STM. Thanks for posting it!.


As tiny purple fishes... run laughing... through your fingers... and you want to take her with you... to the hardland... of the winter.....

and you want to take THEM with you... no?

[Sic]

after being here for quite a bit, this is the first bit of tab i've seen... we are a stopbox forum, but ya know guitars and whatnot... i dunno, guess i just realized i hadn't seen any here before

/end random bit of nonsensical bullocks

[Peter Snowberg]

and you want to take THEM with you... no?

I'm pretty sure it is 'her' although it sounds more like he's saying 'er rather than her.

It is said twice at roughly 1:24 and 2:07.

EC is probably 50% of the reason I picked up a guitar.

[Ansil]

and you want to take THEM with you... no?

I'm pretty sure it is 'her' although it sounds more like he's saying 'er rather than her.

It is said twice at roughly 1:24 and 2:07.

EC is probably 50% of the reason I picked up a guitar.

thats what it says on the dvd when you put it on text mode too.

[Ben N]

Cool idea, I'll have to give it a try (when I get a hold of the Ge diodes)--I guess the next thing is an alnico/ceramic switch!

[jrc4558]

guess you sould emulate the alnico-ceramic by introducing a 470pF capacitor in the feedback loop of opamp. and by a resistor after and in series with input capacitor. Smth like 10k.

[stm]

Hi,

Can you describe the actual difference between Alnico and Ceramic in terms of frequency response and saturation?  I want to understand the components you suggest.  I see the 470pF cap in the feedback loop will introduce some high frequency attenuation.  On the other hand, I don't see the 10k resistor at the input make any significant difference, because input impedance is in hte order of 1 Meg.

Also, I want to clarify that the circuit as it is should be used AFTER your effects and OD/distortion stages.  If you want to have tape saturation and feed it directly with the guitar then you should use pre-emphasis and de-emphasis as shown on the original schematic by the guys from ILXH2.

Regards,

STM

[jrc4558]

Well, yes, my bad. I forgot to mention. Use 10k, but also a 0.0022µF cap to ground. This will form a low-pass filter to emulate the lower high-end response of alnico speakers. Other than that, Alnicos tend to breake up at lower volumes than ceramics... Maybe short out a pair of 1N60's?