Why dose the Soda Meiser Chaos Switch do what it dose????

[carboncomp]

I like the the Soda Meiser with the Chaos Switch, and rate it right up there with other unusable fuzzes like the Ampeg Scrambler 

But I was wonder why adding that extra capacitor into the circuit produces the effect it dose? and can it be introduced to other fuzz pedals?

[MaxPower]

Take a look at the big muff pi.  It's also a fuzz face mod for a smoother/less harsh sound. There are op amp circuits that do the same thing (a capacitor in parallel with the feedback resistor). The cap allows high frequencies to bypass the resistor and blah blah blah... (I'll leave it to someone else to explain).

[anotherjim]

I think what it's actually doing for you is what you'd do yourself on the guitar to get a smooth "violin" fuzz if that cap wasn't there - use the neck p/u and roll the tone treble off. So this cap takes most of the harmonics out of the signal BEFORE it hits the distortion stages. Big Muff uses same idea with smaller caps distributed throughout - these cut the harsher high harmonics made by the distortion, which is not quite the same as only doing it before the distortion, although since it has multiple stages, they're doing a bit of both.

Technical - 1st stage is a common emitter transistor amp, it inverts the signal. Output from collector is reverse polarity of signal in on base - so this cap causes strong negative feedback at high frequencies. It's a low pass filter. A treble cut.

If you've got room for a switch, it's probably well worth fitting it.

[nocentelli]

+1

It's roughly 200 times bigger than the 470p cap commonly used between collector and base in the bigmuff, so it will roll off not just treble, but most of the signal right down to pretty low frequencies. In fact, it's easier to think of the normal mode as being just a significantly reduced gain version of the circuit: when the cap is removed, the whole guitar signal gets the full boost of those three super high gain stages in series, hence the chaos.

[carboncomp]

So, adding a switchable 0.1Uf capacitor in parallel to the muffs 470p will give me a chaotic glitchy Muff switch! 

[nocentelli]

No. Removing the 100n cap gives the soda meiser "chaos" mode: Adding it in reduces the gain down to a more useable/less chaotic level. Adding a 100n cap to the Big muff would just reduce the gain of that stage right down, and give a pretty limp sound.

If you compare the soda meiser gain stages to the first three stages of a BMP schematic, they're pretty similar: The huge (2M2 and 3M3) B-C resistors and grounded emitters, along with the absence of B-C clipping diodes, give the much less refined and much more overblown/glitchy sound of the SM compared to a BMP. There is so much gain on tap, the 100n cap is necessary to damp down the instability of the circuit: With the cap removed, that instability is unleashed.

You can easily get some ridiculous sounds out of the BMP: For a "gate" control, replace the base-to-ground 100k resistor with a 100k pot on one or both of the clipping stages. For overblown nonsense gain levels, add a 100k pot between +9v and the collector resistor on the clipping stages: A dualgang pot would let you freak with both stages at the same time for both of these mods.

[rankot]

I built Soda Meiser and Chaos switch makes it produce some kind of loud noise when nothing is played, and when I start playing distortion is not so extreme. Does it behave like that on your pedals too, or there is something wrong with this one? 

[SprinkleSpraycan]

I hope someone see's this since it's an old thread. I'm building this with the chaos switch and a toggle to switch the last transistor around. On a breadboard it works perfectly. On the strip board everything works except the noise I get when chaos is engaged and I'm not actively playing. When Im not playing there is a load oscillation. What could cause that? I don't see any difference to how it's breadboarded and I check my connections/soldering and there is no undesired continuity.

I built Soda Meiser and Chaos switch makes it produce some kind of loud noise when nothing is played, and when I start playing distortion is not so extreme. Does it behave like that on your pedals too, or there is something wrong with this one? 

[SprinkleSpraycan]

Just thinking out loud from frustration....should I run the other leg of the spdt to ground?

I hope someone see's this since it's an old thread. I'm building this with the chaos switch and a toggle to switch the last transistor around. On a breadboard it works perfectly. On the strip board everything works except the noise I get when chaos is engaged and I'm not actively playing. When Im not playing there is a load oscillation. What could cause that? I don't see any difference to how it's breadboarded and I check my connections/soldering and there is no undesired continuity.

I built Soda Meiser and Chaos switch makes it produce some kind of loud noise when nothing is played, and when I start playing distortion is not so extreme. Does it behave like that on your pedals too, or there is something wrong with this one? 

[antonis]

That should halve input signal amplitude..
(input noise also, in case of there is "some" noise..)