new overdrive "engine"

[earthtonesaudio]

This does cool stuff in the simulation anyway.  Haven't tried it in real life yet.  
link

Slider to the left is typical diode clipper, to the right is something new (to me anyway).  Small peaks clipped; big peaks clean!

[DDD]

Hmmmm... mysterious circuit.
What's the pot value?

[nexekho]

Hmmmm... mysterious circuit.
What's the pot value?

It's 10K.  If you hit the link he posted you can play with it in the simulator.

[Jaicen_solo]

Awesome! So it's like distortion in reverse.
If it works in real life, could be extremely interesting.

[DDD]

Extremely interesting, yes.

[WhenBoredomPeaks]

Extremely interesting, yes.

This.

Think about using this in parallel with a "normal" clipper/distortion, you could get distortion at every amplitude6signal strenght.

[DDD]

Well, if the circuit is able to manage guitar attack processing problems decently, it's great.

[earthtonesaudio]

Here's a more sensitive version (works with 100mV signals, plus a pot to attenuate the input if needed):

link

[WGTP]

IIRC the "alternate" type of distortion is called Crossover Distortion and is used to simulate the effect of a push-pull tube amp.  It is used in the Boss Metal distortions and clones and is typically 2 germanium diodes in the signal path.  It also reduces noise.  Tim Escobedo's TMK distortion includes an adjustable version as well. 

[earthtonesaudio]

Bah, I feel stupid now.  The circuit may be simplified a LOT, resulting in something that looks a bit less mysterious:

link

Different pot settings shown below.

1.


2.

[DDD]

The above shown traces do not look like a crossover distortion at all. They look like an OpAmp-diode clipping but with more "sharp" compression (?)

[Quackzed]

this is alot like diodes through a resistor to ground, in that the signal doesnt hit a hard ceiling at the diodes, rather the diodes conduct a certain amount of signal to ground, and let the rest pass by the diodes un-clipped, so theres always some clean signal blended in, the bigger the signal the more clean signal gets to the output.
it can sometimes sound like a quietish 'distortion' underneath  a cleaner signal... when you play quietly the distortion sound can dominate, when you play louder it gets cleaner , though can be splatty, its somewhat dependant on the amount of clean blended to the output, bypassing the diodes...

http://tiny.cc/4kggo

[DavenPaget]

IIRC the "alternate" type of distortion is called Crossover Distortion and is used to simulate the effect of a push-pull tube amp.  It is used in the Boss Metal distortions and clones and is typically 2 germanium diodes in the signal path.  It also reduces noise.  Tim Escobedo's TMK distortion includes an adjustable version as well. 

Just like that guy who yanked 1 tube off his amp ? Hell yeah .

Just to give some people a clue of what Xover distortion is , Take a Class B amp , hear the distortion you never heard before ? That's Xover distortion .

[CynicalMan]

That doesn't look like crossover distortion to me. It looks more like a TS-type clipping stage with a clever gain control that keeps the peak output constant. I suspect that the diodes are modelled with a series resistance that causes the peaks to look preserved rather than totally clipped.

Edit: Yep, it behaves like a normal feedback clipping stage. You can simulate the circuit with the clipping at max like this.



Still, there's plenty of similar fun you can have with feedback loops. You can turn a clipper into a expander just by putting the diodes from the negative input to ground instead of the output. That's basically diode clipping in reverse. Note that you need to drastically reduce the basic gain set by the resistors. IIRC, it's also called predistortion and was used in tape gear to compensate for the tape's clipping.

[~arph]

Well, it does look like crossover to me. The clipping occurs in the zero crossing of the signal. The peaks look rather unaffected to me.

[DDD]

Crossover distortion causes a flat sections of the signal trace when crossing the "zero" level.
The subject does just the opposite.

[~arph]

I stand corrected

[Skrogh]

Looks like it morphs between Fuzz+clean and overdrive/distortion. Would be interesting to hear this! If you'd like, I can make an LTspice simulation tomorrow, LTspice can export wave-files.

[Skrogh]

I went ahead and did a simulation with a sample i found on the interwebs:
http://soundcloud.com/skrogh/sets/diy-stopbox-demo-sounds-1
I like it! :3
Might do a bass sim. later, and see if it's something I'll have to build.

[earthtonesaudio]

Awesome, thanks Skrogh!  This is the first time I've heard a circuit before building or even breadboarding it.