Recommend me a DIY fuzz circuit

[Booya Tribe]

I am looking for something a little rough around the edges - not regular distortion or overdrive, something with more character. Plastic, bad solid state fuzz what I am looking for, though something with sustain is nice too.

 

I was looking at these, but I don't know my fuzz pedals, so I don't know what to build:

 

http://www.generalguitargadgets.com/index.php?option=com_content&task=category&sectionid=6&id=73&Itemid=26

 

Something that uses common transistors and a simple circuit would be cool, but hit me with what you got. None that I have seen so far look very challenging anyway.

[Booya Tribe]

As an addition, I just found this schematic when searching. It is supposedly a fuzz circuit os mutantes used which is right along the lines of what I am looking for. It is also really simple.

 

 

Two questions, if anyone knows

 

1. Where is the power hooked into the circuit?

2. What would happen if you didn't use germanium diodes?

 

Does that schematic make sense? I also notice the output is pointed at the middle of a resistor and it was described as being a one knob fuzz, but there is no indication of a knob on there...

[nos]

As an addition, I just found this schematic when searching. It is supposedly a fuzz circuit os mutantes used which is right along the lines of what I am looking for. It is also really simple. Two questions, if anyone knows 1. Where is the power hooked into the circuit? 2. What would happen if you didn't use germanium diodes? Does that schematic make sense? I also notice the output is pointed at the middle of a resistor and it was described as being a one knob fuzz, but there is no indication of a knob on there...

 

I actually have that one on a breadboard right now. It's pretty cool sounding although I'm not set on which transistors and caps I'm going to use yet. Funny thing is, I've been doing pedals for about 6 or 7 years now and this is my first time breadboarding and experimenting. I usually stick to the game plan and build projects exactly as specified.

 

Anyway, the power would connect anywhere along that top "rail". It connects to the four resistors. The 2.5k and 5k resistors provide the proper bias for the transistors.

 

The bottom rail is ground.

 

The resistor with the arrow on the far right is a variable resistor (pot). One lug goes to signal, the other lug goes to ground, and the wiper (center lug) is your output. This is common. Your signal enters the pot. Some signal is shunted to ground, dependent on how much the pot is turned. The rest of the signal exits via the wiper. Make sense?

 

You can use any NPN transistor in this circuit. Can't tell you what effect they would have, but the circuit would work. Just watch pinouts. Who knows, you could discover something totally new and cool. Although Os Mutantes were pretty damn cool.

[Booya Tribe]

 

I actually have that one on a breadboard right now. It's pretty cool sounding although I'm not set on which transistors and caps I'm going to use yet. Funny thing is, I've been doing pedals for about 6 or 7 years now and this is my first time breadboarding and experimenting. I usually stick to the game plan and build projects exactly as specified. Anyway, the power would connect anywhere along that top "rail". It connects to the four resistors. The 2.5k and 5k resistors provide the proper bias for the transistors. The bottom rail is ground. The resistor with the arrow on the far right is a variable resistor (pot). One lug goes to signal, the other lug goes to ground, and the wiper (center lug) is your output. This is common. Your signal enters the pot. Some signal is shunted to ground, dependent on how much the pot is turned. The rest of the signal exits via the wiper. Make sense? You can use any NPN transistor in this circuit. Can't tell you what effect they would have, but the circuit would work. Just watch pinouts. Who knows, you could discover something totally new and cool. Although Os Mutantes were pretty damn cool.

 

 

What kind of diodes did you use?

 

I actually found another diagram showing the power, ground, and ouputs and with a description and instructions, and I finally also realized what you were saying about the upper and lower rails, which then made sense electrically...

 

Apparently it was printed in a Brazilian magazine... this is a site with a lot of circuits. There are a few circuits there which look pretty interesting to me.

 

Thanks for the info, BTW.

[nos]

No prob. I used a pair of 1N34A diodes that I had in my parts drawer.

[Booya Tribe]

You can not substitute silicon or other diodes for the germanium ones, can you?

 

I only ask because I have all the parts on hand except germanium diodes.

[nos]

 

You can not substitute silicon or other diodes for the germanium ones, can you? I only ask because I have all the parts on hand except germanium diodes.

 

 

You sure can. But at that point you'd be affecting the tone quite a bit. Don't ask me in what way; I'm definitely not a fuzz connossieur like some people are. If you wanted to, you could always build it with the Si's and swap them out for germs when you get them. They're cheap.

 

In fact, if you have sockets it would be really easy. I've used IC sockets and cut them with diagonal wire cutters down to the right size for transistors or diodes before.

[Booya Tribe]

 

You sure can. But at that point you'd be affecting the tone quite a bit. Don't ask me in what way; I'm definitely not a fuzz connossieur like some people are. If you wanted to, you could always build it with the Si's and swap them out for germs when you get them. They're cheap. In fact, if you have sockets it would be really easy. I've used IC sockets and cut them with diagonal wire cutters down to the right size for transistors or diodes before.

 

 

Hey, that's a great idea about the diode sockets. I have more IC sockets than I know what to do with...

 

I actually have a bag full of random diodes so I should look through to make sure that I don't have some germanium ones in there, but I am pretty sure I don't.

[nos]

Thanks for the link! Pretty cool circuits!

[Booya Tribe]

Yea, it is weird a few of them of are from old Brazilian magazines...

 

I think I am going to try that simple diode octave doubler.

[Booya Tribe]

I've got this thing laid out on a perfboard but haven't soldered it yet.

 

One question - any idea what that .0047uF capacitor with the switch on the input is for? I assume that essentially cuts the capacitance in half on the input, right? What does that do in practical terms with the fuzz? I could also have a SPDT switch that switches between a 10uF and 4.7uF capacitor and get the same result, right?

 

I am just trying to learn a little bit about this stuff as I go through it. I have been building stuff on and off for over 10 years, but have only a very basic understanding of how it all works.

 

[Mr.Grumpy]

One question - any idea what that .0047uF capacitor with the switch on the input is for? I assume that essentially cuts the capacitance in half on the input, right? What does that do in practical terms with the fuzz? I could also have a SPDT switch that switches between a 10uF and 4.7uF capacitor and get the same result, right?

 

Yes, the switch across the cap greatly reduces the capacitance... basically it will block low frequency, "bassy" signals from reaching the fuzz circuit. It will make the fuzz less "farty" sounding, but will also reduce the drive. The switch cuts the capacitance radically - from 10 mfd to 5/1000th of a microfarad. Those parts (the 0.0047 mfd cap and bypass switch) are optional, the fuzz will work without it. The main input cap 10 mfd, could be switched out for a different value too, if you'd like to experiment. My 2N2222 based fuzz circuit uses a 1 mfd input cap, that seems to be a good compromise between "drive" without too much fartiness or muddiness.

But it also depends on the gain of the fuzz amp. Pay attention to the decimal point on cap values! .1 mfd is not the same as 1 mfd, it's 10 times less.

 

The clipping diodes are also "non-critical" components. You could omit them entirely and the fuzz will still work, although it may have an excessively high output... Almost ANY diode will work for clipping diodes, Germanium, silicon, LEDs. Experiment and see what you like.

 

Basically, the clipping diodes work to limit the maximum voltage across them. Once the voltage exceeds the diodes' "forward voltage" they begin conducting electricity and and limit the voltage. Germanium diodes typically have a forward voltage of 0.3 v, where Silicon diodes are closer to 0.7 v, so you'll have more output with silicon clipping diodes. As far as TONE, that's just something you'll have to judge for yourself. I'd recommend tweaking the circuit in breadboard form before committing it to solder.

[Booya Tribe]

Thanks for all that info Mr.Grumpy. It does help me to understand what is going on there. I had messed up my math on calculating serial capacitor capacitance. (C1xC2)/(C1+C2)....

 

So in this case, (10x.0047)/(10+.0047) = .047/10.0047 = about .0047uF

 

So essentially, could you get close to the same result by having the switch just bypass that initial 10uF cap? Or would the .0047uF cap actually produce a noticeable cut in the bass when it is inline?

 

I would like to be able to experiment with this stuff. I need to get a breadboard kit. I always just solder and then wait to see the results

[drewl]

DON'T DO IT!

Whatever you do you'll get hooked!

I've built like 30 pedals in last year or so

[Booya Tribe]

 

DON'T DO IT! Whatever you do you'll get hooked! I've built like 30 pedals in last year or so

 

 

I've been doing one project a week for the last few weeks...

 

I've got one more in the plans after this one... after that, I can quit any time, I swear.

[irishstu]

DON'T DO IT! Whatever you do you'll get hooked! I've built like 30 pedals in last year or so

 

Ha ha

[Booya Tribe]

Here it is...

 

I made it stock minus the switch for the input cap option for the time being, and I used silicon diodes (4004) because they were what I had around. I did use a socket though for the diodes so I can switch them out and experiment. I also soldered in a wire for an optional switch to another value input cap, so I can go back and try some more things with it.

 

I tried it out and this fuzz is such a funny thing... it really could be any input on any circuit being blown out, but it sounds good... ok, well it sounds better than the preamps on my old 4 track being blown out...

 

it really doesn't work unless you turn down the tone knob on the guitar. I mean, it works, but there is no sustain and almost no volume. I'd like to do some experiments to see what else I can get out of this simple circuit.

 

I built it into the box from a vintage walkie talkie. The circuit is less noisy than I expected considering a plastic box and no shielding on the wires. All in all I can't complain, does what I was looking for.

[nos]

 

Here it is... I made it stock minus the switch for the input cap option for the time being, and I used silicon diodes (4004) because they were what I had around. I did use a socket though for the diodes so I can switch them out and experiment. I also soldered in a wire for an optional switch to another value input cap, so I can go back and try some more things with it. I tried it out and this fuzz is such a funny thing... it really could be any input on any circuit being blown out, but it sounds good... ok, well it sounds better than the preamps on my old 4 track being blown out... it really doesn't work unless you turn down the tone knob on the guitar. I mean, it works, but there is no sustain and almost no volume. I'd like to do some experiments to see what else I can get out of this simple circuit. I built it into the box from a vintage walkie talkie. The circuit is less noisy than I expected considering a plastic box and no shielding on the wires. All in all I can't complain, does what I was looking for.

 

 

Looks great! You come up with some great enclosure ideas.

 

Do you have some different transistors to try? They might drastically change the behavior for the better.

[Booya Tribe]

 

Looks great! You come up with some great enclosure ideas. Do you have some different transistors to try? They might drastically change the behavior for the better.

 

 

I have had this enclosure sitting around for probably 10 years, just waiting for a good use for it. Finally!

 

Yea, I do have some other transistors around, though it might be interesting getting the current ones out of the circuit as some of the leads are bent to meet with other components on the board.

 

I am going to see what happens with some different diodes and input cap experiments first...

 

Edit: I have one additional question about this circuit, if anyone knows - what path does the input signal actually travel down? For example, it seems to me that the signal from the input would be coming in the transistor at the base pin, but where is it coming out? Logically, from the name, I would think it is coming out the emitter, but that goes to ground... I am still just getting a grasp on how transistors actually work.

[nos]

I'm at work so I can't draw anything up or you (no mspaint). But basically the signal goes "right up the middle" if you're looking at the schem. Take away the power rail and its 4 resistors, the ground rail and the two diodes and what you're left with is the signal path.

[Mr.Grumpy]

Edit: I have one additional question about this circuit, if anyone knows - what path does the input signal actually travel down? For example, it seems to me that the signal from the input would be coming in the transistor at the base pin, but where is it coming out? Logically, from the name, I would think it is coming out the emitter, but that goes to ground... I am still just getting a grasp on how transistors actually work.

 

The audio portion of the signal "travels" from left to right. The signal comes in, passes through the 10uf cap, is amplified by the first transistor, then the audio passes through the .1 uf coupling capacitor, then amplified by the second transistor, then passes through the last coupling capacitor, then on to the clipping diodes, and volume (output) control.

 

Yeah, basically what nos said...

[Booya Tribe]

That description makes sense, and is basically what I thought... so the signal comes out of the collector on the transistors then?

 

I thought that the collectors are what draw in the power to amplify the signal. There is probably something fundamental that I am not understanding about transistors.

[Booya Tribe]

I got a chance to play around with this some more and play it with an amp up a little louder, and I actually like it a lot. It does sound a lot like the fuzz used by Os Mutantes on certain songs (they use a lot of different sounds and effects). It gets nice and thick and buzzy, sort of pulsewidth modulation sound. Reminds me of the way an overdrive pedal sounds when the battery is dying. I always wished I could get that sound more permanently.

 

It also sounds great following the Kay tremolo I made this weekend - because the fuzz limits smooths and compresses the dynamics of the tremolo coming in, it makes the trem sound more like a vibrato due to the modulation in square wave width that is going on with the rapid volume changes and different amounts of clipping that produces.

 

I did some experimenting with different caps on the input switch, and found that I wasn't satisfied with the difference in sound with the stock suggested .0047uF, so I put in a .001uF capacitor on the switch for a more obvious difference in sound. It has a very harsh, treble sound with not much sustain - a lot of contrast to the deep, full buzz and sustain of the 10uF cap.

 

The .001uF cap actually sounds really wild when you turn the tone knob down and use out of phase bridge and neck pickups - almost like a wah set static somewhere in the middle. This is now a good variation in sounds I can get from this simple box.

 

I also tried substituting larger value input caps in place of the larger 10uF one, but I didn't notice any difference in sound even with caps several times larger.

[nos]

 

I got a chance to play around with this some more and play it with an amp up a little louder, and I actually like it a lot. It does sound a lot like the fuzz used by Os Mutantes on certain songs (they use a lot of different sounds and effects). It gets nice and thick and buzzy, sort of pulsewidth modulation sound. Reminds me of the way an overdrive pedal sounds when the battery is dying. I always wished I could get that sound more permanently. It also sounds great following the Kay tremolo I made this weekend - because the fuzz limits smooths and compresses the dynamics of the tremolo coming in, it makes the trem sound more like a vibrato due to the modulation in square wave width that is going on with the rapid volume changes and different amounts of clipping that produces. I did some experimenting with different caps on the input switch, and found that I wasn't satisfied with the difference in sound with the stock suggested .0047uF, so I put in a .001uF capacitor on the switch for a more obvious difference in sound. It has a very harsh, treble sound with not much sustain - a lot of contrast to the deep, full buzz and sustain of the 10uF cap. The .001uF cap actually sounds really wild when you turn the tone knob down and use out of phase bridge and neck pickups - almost like a wah set static somewhere in the middle. This is now a good variation in sounds I can get from this simple box. I also tried substituting larger value input caps in place of the larger 10uF one, but I didn't notice any difference in sound even with caps several times larger.

 

 

Cool! Yeah, you can't get those sounds from a Fuzz Face! I'll box mine up one of these days. I already have all the parts on breadboard, but I'm experimenting with an enclosure finishing technique and it's been an ongoing battle (which I've been losing).