Instructables

Distortion Pedal With Stutter Effect

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This was built for a friend who asked me for a distortion pedal for him to use with his guitar.The main distortion effect is achieved though an LM386 audio amplifier IC which clips the signal. There is also a stutter effect which turns the output signal on and off at a user-specified rate. This is controlled by one of the three potentiometers (the others control Gain and Output Volume). An NE555 timer IC generates a square wave which turns the amplifier section on and off. The 555 oscillator circuitry and the original idea are based on a design by spel3o.

The stutter effect isn't to everybody's taste, so I added a toggle switch to switch it out of the circuit. A bit of advice - the NE555 timer generates a fair bit of noise and pops on the power supply, so I wired the switch to also remove power from the NE555.

 
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Step 1: Parts list

Picture of Parts list
The following components and parts were used in this project :

(1x) Die-cast aluminium enclosure - I used the Hammond 29830PSLA
(3x) Potentiometer control knobs
(1x) Heavy-duty latching DPDT push switch
(2x) DPDT miniature toggle switches
(1x) 2.1mm DC power socket (Use a plastic body one if you are using a metal enclosure!)
(2x) 1/4" jack sockets
(1x) 5mm LED bezel
(1x) Battery snap
(1x) PP3 9V battery
(1x) Piece of stripboard
(2x) 8 pin DIL sockets
Various lengths of stranded-core wire

(1x) 10K potentiometer
(2x) 100K potentiometers
(1x) 470R resistor
(1x) 1K resistor
(3x) 10uF electrolytic capacitors
(1x) 220uF electrolytic capacitor
(1x) 0.1uF (100nF) polyester or ceramic capacitor

(1x) 5mm LED of your favourite colour
(1x) NE555 timer IC
(1x) LM386 audio amplifier IC

Step 2: Circuit diagram

Picture of Circuit diagram
Here is the schematic diagram for the circuit. If you choose not to build it on stripboard, you can build it according to this instead. To see an enlarged version of it, the link is here: http://www.instructables.com/files/orig/F6Y/ODX1/GWF65G6U/F6YODX1GWF65G6U.png

Step 3: Stripboard layout

Picture of Stripboard layout
In this diagram, the little red squares with dots in the middle represent track breaks. Watch out for the track breaks under components. To see an enlarged version of it, the link is here: http://www.instructables.com/files/orig/F00/2TCN/GX10LFOR/F002TCNGX10LFOR.png

Hey, is it possible if i don't want to use power jack for the power source??only the 9v battery.

Tegdim5 months ago
I built one of these. The distortion works fine but the stutter doesn't work at all, just cuts the signal. anyway, here's a photo of it
IMG_0960.JPGIMG_0963.JPG
glitchface7 months ago
Hey guys.. anyone else experience intense heat from the 555 chip? is that normal?
tomithy12358 months ago
Okay great, thanks!


Also though, what about that SPST switch, it's not anywhere in the materials section. so is it actually one miniture SPST switch and one mini DPDT switch? (and then the heavy duty DPDT switch is still the same)
tomithy12358 months ago
On the stripboard layout, I have a couple confusions...

first, I noticed that all the wire jumps are using blue lines, except for one which is green. Is that simply because it is not just a vertical jump (but also moves from one side of NE555 to the other).


Also, there seems to be a jump on the bottom two strips, near the center, with those two blue short lines going into a green circle. I want to just assume it's a normal jump, but I feel like it can't be! I've been trying to follow the circuit diagram, but haven't found much help.

Sorry, this is the first thing I've ever built, so I'm easily lost. Thanks!
Oh and one more thing, for the switches. The stripboard layout has a SPST switch, but the materials section only says DPDT switches, so what's up with that?
Harrymatic (author)  tomithy12358 months ago
Hi, the blue lines are jumper wires, as are the green lines. The green circle represents the power LED. You can leave it out if you don't want it.
Tegdim8 months ago
Hi there, I'm going t make this pedal and I was wondering what you mean by 'Track Breaks' in step 3? Thanks
Harrymatic (author)  Tegdim8 months ago
that's where you cut the stripboard tracks. this is usually done with a small knife or a 5mm drill bit
adark9 months ago
i am still don't know what to do :((
adark9 months ago
yes it is easier like you said but the backward part is hard i cant see how it is
Harrymatic (author)  adark9 months ago
the best way to work with stripboard is to look at it with the non-conductive side facing you. Poke a pin or something through the holes where there will be a break on the other side, so you will be able to see which hole it is. Having done this, mark on with a sharpie marker the location and then go back and cut the tracks where you have marked.

there are probably some really good stripboard tutorials if you look on google or youtube.
adark9 months ago
man please have a explain on ic ne 555 it is like : 1 8
2 7
3 6
4 5
now how can i change it to be like your explanation:
4 8
7
6 3
2
1 5
???? realy confused or should i just like the schematic :
1.connect pin 1 to 10uf
2.pin 2 to 10 uf +
3.pin 3 to the middllest 10 uf
4.pin 4&7 to the 470
5.pin 8 to the 470 and shutter
is this steps right ?
Harrymatic (author)  adark9 months ago
The numbers on 555 on the schematic diagram correspond to the pins. It's drawn differently as it makes the schematics easier to read. If you are confused, I recommend you just follow the stripboard layout as it doesn't require an understanding of electronics theory.
myonus9 months ago
Im going to double this circut. so I have 2 stomp switches/ 6 pots/ 2 leds. What I hope for is Two distortions settings/ and two stutter settings/ or double the whole mess for a double messssyyy. Add my EH analog delay and blam! Make my neighbors move out! woo hoo!! any advice or suggestions?
sdcharle10 months ago
Personally I love that stutter effect. Great project, I'm gonna build one...
abyssinianloop11 months ago
Thanks for the reply. It turned out that my 470 ohm resister was bad. Once I replaced it, the stutter effect started working more like in your example. The only thing that's still not perfect is the stutter effect is audibly pulsing even when I'm not playing my instrument. I think some other people talked about having that problem too. If I can get that solved I'll be golden.
abyssinianloop11 months ago
This is such a cool sounding pedal and I'm so close to getting it working. The distortion works as well as the gain control and master volume. But when I switch into stutter mode, it only cuts my signal when set to a very slow rate. When I increase the rate, my instrument signal isn't interrupted. And, the fastest rate I can get isn't very fast at all. Anyone have any ideas of what might be wrong?
Harrymatic (author)  abyssinianloop11 months ago
Your problem sounds like a defective potentiometer on the rate control. Try swapping it for a different one.
Any specific reason why you used Linear taper pots as opposed to log pots? Will log taper pots still work? Also, where can I get more info on the wiring between the 9V, board, and DC socket? Is the ground wire running into from the battery, into the toggle, and then onto the board? Sorry if that's a bone head question. I'm just getting into circuits.
D.A.N1 year ago
Followed the strip board diagram twice, still not working, any ideas where i could be going wrong, i'll post pictures if it helps.
D.A.N1 year ago
Hi there, i was wondering if there would be any repercussions if i tried to reduce the size of the circuit by placing things closer together where possible or does the space between components have a relevance to the circuit?
Harrymatic (author)  D.A.N1 year ago
I doubt that there would be any noticeable difference if you were to move components closer. The only reason they are spaced out a bit is so that the stripboard layout is easier to assemble.
Abbaheart1 year ago
Very clever...
I would have never thought of these two chips put together.
what does the second toggle on the back do?
Harrymatic (author)  tronicdude61 year ago
I don't know which one you are talking about, but one turns power on and off and the other enables/disables the stuttering effect, leaving just the distortion.
I tried looking for the capacitors and they seem to have different voltage ratings. Am I supposed to look for a 9v one?
Harrymatic (author)  trueblue44441 year ago
pretty much any voltage capacitor will work for this project.
great instructable it works perfect. but im completely lost on this bypass switch. what is the signal?
I used your circuit diagram to attempt building my own pedal, only without the stutter, as I will add that in later, mainly depending on when I can get the parts I need. Everything seems to work fine so far, except there is an annoying high-pitched whining nose no matter what I do. I have a 10uf capacitor between pins 1 and 8, pin 2 is sent to ground, 3 is connected to my guitar cable, 4 grounded, 5 is outputting to a small 8ohm speaker that I am using for testing so I don't accidentely ruin my amp, but I have confirmed the problem was not in the speaker because I have tried plugging into the amp. Pin 6 is connected to the 5v pin on my Arduino Uno until I can get a battery, and all grounds are grounded to the Arduino's ground. Pin 7 is unattached, and there is nothing else in the circuit. No potentiometers, buttons, switches, capacitors (other than the one between 8 and 1), or resistors. I've tried various different combinations of capacitors and resistors both between the LM386 and the audio input, and between the LM386 and the output, but nothing seems to work. Any ideas?
Nvm, leave it to me to work hours on something, then once I finally decide to ask for help I find a solution. A 470uf capacitor between pin 3 and the guitar cable did the trick.
Do those switches turn the distortion on/off and stutter on/off? can you actually get the stutter alone? or is it always the two together
TobaTobias1 year ago
Great instructable, but which are the effects output/input?
Harrymatic (author)  TobaTobias1 year ago
Sorry for not making this clear - the effect input/output is labelled as 'Audio In/Audio Out' on the main stripboard layout diagram.
No worries, thanks mate ;)
Cool stuff! I'm currently building a germanium transistor fuzz face, do you think I could make it stutter with a 555? I just don't like the 386.
Harrymatic (author)  BeerPowered1 year ago
This circuit should do the trick - just connect it up to the power rails and the audio line to the output of your fuzz circuit :
simple stutter.gif
fugyeh1 year ago
Can't wait for this little build. Do you think I could use a 556 instead of the 555. A 556 is just 2x 555 basically. Thanks!
Harrymatic (author)  fugyeh1 year ago
It would be absolutely fine, but it would complicate the design a bit, as it has a different pinout to the 555.
Do you remember which capacitors you used? I really liked the lack of ticking and noise in your sample and would love to re-create that. I made a working version as well now by the way, so thanks for the guide! Would love some noise-reduction though.

Oh and one more thing I noticed, when I turn the volume on my guitar down to about 50% the guitar doesn't send a signal to the amp anymore, but the noise and ticking of the pedal does get through. I'm not sure if anyone else noticed that or if it's just me.

Thanks!
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