Mystery Circuit

[Thunderscreech]

Some of you may have seen this before, but I found it in a pile of papers. It's from a tear or so ago when I was doing a project for physics. I got it on the internet from somewhere.

But, what does turning the pot do to the sound?



EDIT: you know, I haven't had anything to drink and I still can't type.

[B.C.]

Originally Posted by Thunderscreech

Some of you may have seen this before, but I found it in a pile of papers. It's from a tear or so ago when I was doing a project for physics. I got it on the internet from somewhere.

But, what does turning the pot do to the sound?



EDIT: you know, I ahven't had anything to drink and I still can't type.

Thats a pretty neat circuit. RG Keen designs some pretty cool stuff.

[Thunderscreech]

What does it do?

[anechoic]

Originally Posted by Thunderscreech

What does it do?

I'm gonna guess that turning the pot adjusts the DC bias on the diodes, which in turn changes where they clip, and gives some control over the harmonic content?

[metalmariachi]

The pot controls the neg feed back to the first op amp ala Rat.
Should control gain ie distortion.

MM

[warnergt]

Originally Posted by anechoic

I'm gonna guess that turning the pot adjusts the DC bias on the diodes, which in turn changes where they clip, and gives some control over the harmonic content?

I agree. The pot might adjust the voltage at the diodes. Adjusting the
pot affects where the signal clips. In other words, the circuit introduces
distortion. Adjusting the pot simply changes the nature of the distortion.

[B.C.]

Originally Posted by anechoic

I'm gonna guess that turning the pot adjusts the DC bias on the diodes, which in turn changes where they clip, and gives some control over the harmonic content?

Exactly, the OP Amp config with the Diodes acts as a precision rectifier, so essentially it is controlling signal clipping.

[Deluge Of Sound]

Correct me if I'm mistaken, but I believe that's the circuit to this pedal:

[B.C.]

Originally Posted by Deluge Of Sound

Correct me if I'm mistaken, but I believe that's the circuit to this pedal:

Well, its probably a bad clone. I mean, from what I can see there is only one pot and one variable resistor. Your pedal has three.

[anechoic]

Originally Posted by Deluge Of Sound

Correct me if I'm mistaken, but I believe that's the circuit to this pedal:

Had they used a DOD pedal for this picture, I might have believed that the labels on the controls were real. It's slightly less silly than knobs labeled "meat" or "butt".

[katri]

I bet that boss pedal sounds awsome. Especially with everythin cranked.

[anechoic]

Originally Posted by B.C.

Exactly, the OP Amp config with the Diodes acts as a precision rectifier, so essentially it is controlling signal clipping.

Hmm, now this has me wondering if the precision recitifier portion might be adapted for use in a ring modulator circuit, as sort of variation on the classic passive four diode circuit. (I'd actually feed both inputs with the same signal for an octave doubling effect.)

[B.C.]

Originally Posted by anechoic

Hmm, now this has me wondering if the precision recitifier portion might be adapted for use in a ring modulator circuit, as sort of variation on the classic passive four diode circuit. (I'd actually feed both inputs with the same signal for an octave doubling effect.)

Interesting. Having not played with it however, I'm going to venture yes but I'm not sure it would be worth it. What this does is actually behave more like an ideal diode than an actual diode(the beauty of OP Amps ). So I suppose in theory you could arrange it like a full wave bridge rectifier, but I'm not sure it is worth it. Let me know if you think of anything. O and here is an article about this particular configuration. http://en.wikipedia.org/wiki/Precision_rectifier

[Thunderscreech]

Okay, so to revisit this: What would happen if I stuck this in a Big Muff circuit somewhere? Or could I stick it in a Big Muff circuit somewhere?