Introduction: Simple Overdrive Effect Pedal

This is a very simple overdrive effect. There are a lot of same kind of effects on the net, but I decided to design something simple. It's a great beginner project.

This is me playing with it:
http://youtube.com/watch?v=z-1BsJz9Cpk
First I play clean, the switch on the effect.

Step 1: Diode Clipping

Overdrive or distortion occurs, when signal is amplified too much. Amps have an upper limit of volume. If a sound signal is louder than then it's peaks are simply chopped off. That is called clipping (distortion).

We can simulate clipping, by placing diodes between the signal and ground.



Step 2: The Schematic

Now it's time to build one for yourself too!

This is what you need:

6.3mm stereo female jack
6.3mm mono female jack
DPDT switch
0.1uF capacitor
LM386 op-amp
220uF electrolytic capacitor
47k resistor
100k resistor
red LED
two 1N4148 diodes

Incase you don't know, how to read schematics, there are a plenty of tutorials available. Just Google

Comments

author
JatinK007 (author)2016-02-10

Can we use this pedal for bass guitar too? Or is it only for guitar?

author
marrymay (author)2015-01-26

Excellent write-up. I absolutely appreciate this post. I did try this way to build an overdrive pedal! and it's nice, check on this overdrive pedal

author
cardboarddude (author)2013-02-23

I built the circuit and when I connect it to my guitar, I hear the radio! What did I do wrong?!!

author
ilovegm (author)cardboarddude2013-10-20

Shielding, enclose the electronics in a conductive material of sorts (faraday cage)

author
tsamarakoon (author)2013-03-28

Instead of 1N4148 diodes, could I use 1N5818 schotky diodes? and for the OP amp, should it be an LM386? Can't it be another op amp model?

author
666sebas999 (author)2013-01-12

Something wrong happened, It didn't work and I tried to figure out what happened; I found this, even with the effect on bypass the signal isn't going through; when I unplug the DC power, signal goes through bypassed-effect. This have never happened to me before, can someone explain me what just happened?

Thanks :)

author
maheshsankaran (author)2012-09-05

I found that by connecting the diodes to the switch (top right point of the switch) rather than to ground, I get much more distortion. With the circuit as shown above, I get lots of overdrive, but hardly any distortion. Does that make sense?

author
yrosema (author)2012-07-28

I made mine like this:

added drive pot and 2x 1M resistor because it was too loud.

disto2.bmp
author
badad (author)2012-05-08

does it need another kind of jack or the regular will work?

author
Jahiruddin (author)2012-05-03

Dear
Thank you for provide this circuit diagram but now I like to test sound . Is it possible . Please help me.
Jahir

author
Jahiruddin (author)2012-05-03

Dear
Thank you for provide this circuit diagram but now I like to test sound . Is it possible . Please help me.
Jahir

author
yrosema (author)2012-05-03

I read somewhere that if I use a 100uF capacitor in stead of the 0.1uF one I'd get more bass. Is that true?

author
666sebas999 (author)2011-07-22

Does it need to be a LM386?
because i get a LM731 from an old recorder, can I use it too?

author
pfred2 (author)2011-09-29

You had me all pumped up what happened?

T33.jpg
author
serverfp (author)2011-05-26

Como puedo descargar los pdf ayudenme chicos

author
91chevywt (author)2009-08-04

Hey i've got a quick question for you. I've got everything together, as indicated in the diagram, and when I have it hooked up all switching the switch does is amplify the sound almost double. There is no distortion, just loud and clean. Do you have any idea what could be causing this? I checked my resistances with an ohmmeter and they seem to be in line with what the schematic calls for. Other than that i'm not sure what else to try.

author
odopudj (author)91chevywt2011-04-24

Try pins 1 and 8.connect directly or put 10 uF capacitor between pins

author
PowerslaveNSHC (author)2009-09-05

Can someone write me schematic for volume pot or gain pot or both of them? Regrets and thanks!

author

PICKO madjarska stavi pot od 100 k tamo gde ti cika stewa reko!!on je dobar covek slusaj ga!!!al dzabe ti kad nemash lemilicu XD eheheh

author
odopudj (author)Guitar_slave2011-04-24

Opa!Gde ste Balkanci xD

author
MGZero (author)2010-05-23

I'm curious as to why you have the clipping part in parallel rather than in series.  Wouldn't that cause a short circuit from the capacitor to the switch?  If that's the case then all of the current is going to bypass the diodes and such and then you won't get any distortion.  Can someone confirm this for me?

author
odopudj (author)MGZero2011-04-24

Not really. When u have two directions of current, the current is divided into the two paths.In this case is the way to bypass the less resistance, so there goes more electricity, but also going through the LED.:) (bad eng,sry)

author
moogbeatz99 (author)MGZero2010-08-24

i think you are correct.

author
MGZero (author)MGZero2010-05-23

Nevermind, after doing some research on diodes, I understand what's going on here now.

author
ski4jesus (author)2011-03-17

Just so you know, on my LM386 amp, I have a 10uF capacitor between pin 1 and 8 with a switch and it gives off louder signal and tons of distortion, all the distortion you should need, but im going to try this anyway good job.

author
oweng4000 (author)2011-02-11

Can I use the image of the clipped and unclipped waveform for a science project I'm doing? Just wanted your permission before I used it.

author
coolguy2015 (author)2011-01-16

will this work..

author
shmecker (author)2010-10-18

How about adding a 10uF capacitor between 1. pin and 8. pin for some more distortion? Also, adding a switch there is a good idea as far as I am concerned.

author
Schmidtn (author)2010-02-09

Maybe a silly question but, why is it a stereo input jack instead of a mono jack?  Though all guitars were single channel (but I don't know anything about making guitar pedals, so I'm asking). 

author
magnus0 (author)Schmidtn2010-02-09

 it's actually a power switch. when the input cable is plugged in, the power is turned on, if it's plugged out, it's turned off.
the guitar's mono plug will connect the ring and sleeve on the input plug, this will connect the power.

author
MGZero (author)magnus02010-05-22

That doesn't make sense.  Regardless of whether or not that is connected you're still going to have current draining from the battery through the op amp because of the ground.  The current is going to go through the op amp, drain to ground, and then return to the negative of the battery, which completes a circuit.  You sure this schematic is right?  I'm having quite a few problems with it.

author

well a batterey doesent drain a lot when u dont comeplete th circut

author
Bodygard1117 (author)2010-07-30

Crack that baby open and show us the insides. You know just to see how you laid it out.

author
-Syrus- (author)2010-06-30

How about connecting LM386's pin 1 & 8 together? This increases the gain, big time. More disto = more fun ;)

author
MGZero (author)2010-05-18

I accidently grabbed a .01 uF capactiro instead of a .1uF, is this going to cause any major problems?

author
kgyll (author)2010-05-12

 okay... how many volts of the 220uF electrolytic capacitor? and... 6.3mm stereo/mono female jack looks too small... reply to me ASAP

author
Phosphorus (author)2010-03-25

If I use a 0,1 uF electrolythic capacitor, which is the correct orientation? Positive to the left?

author
oweng4000 (author)Phosphorus2010-04-08

 the input from the guitar should go in the positive section. BTW, Where in the world did you find a 0.1 uf electrolytic capacitor?

author
alwaysmisternoise (author)2010-03-05

I think this is a great instructable!!!!  Although- the LED and Diodes section does not have any effect on the circuit....  you can disconnect them and the overdrive still works!!!!

author
jerrykinda (author)2010-03-04

does it work for bass guitar?

author
Kin0 (author)2010-02-12

do you know how to wire DPDT switch the way he will bypass the battery will be off.

author
luudvig (author)2010-02-01

Hmmm... I only got amplified sound, no overdrive

author
Ninjanator (author)2009-11-22

THIS INSTRUCTABLE IS A LIE I SPENT 20 DOLLARS ON PARTS AND IT DIDN'T WORK SO NOW I AM REALLY MAD AND I BLAME YOU RESPONSIBLE FOR IT. I FOLLED EVERY STEP AND IS DIDN'T WORK SO IT'S ALL YOUR FAULT I HOW YOU FEEL GUILTY FOR THIS

author
Joanassie (author)Ninjanator2010-01-11

You were the one who decided to go for it, you don't realize that many F/X pedals cost much more than that, and it may have been something as simple as one part that broke. It's why people should always use a multimeter or breadboard to test their components. As well, please don't use bold capslock. It's the equivalent of homicidal rage, while you are likely feeling just a tiny bit annoyed. Unless you don't know the value of a dollar. Which is 0.69 Euros at the time of writing.

author
z-man6233 (author)Ninjanator2009-12-04

I works perfectly you just screwed up and its 20 dollars wow not that much.

author
fatfoohy (author)2009-12-15

why would you put an LED in the audio circuit? wouldnt you want to wire it apart from the audio so that you don't introduce LED clipping,  Speaking of this i am planning to build one of these with a switch to move between LED, silicon, and germanium diode clipping, will post pics

author
gmoon (author)2009-12-08

Comment or two:

-- The clipping portion is very similar to my diode clipping instructable, right down to the resistor values and specific diodes. That ain't no big thang. I didn't invent the concept. But those diode and resistance values are tuned to my amp specifically. If you copped it from me, you might get better results by customizing the values, for the voltage peaks of this circuit.

-- More importantly--the coupling cap on the output of the 386 is right out of the datasheet. But that capacitance value is correct for driving a speaker load, rather than for a preamp driving a higher impedance load.

In addition to blocking any DC offset, that coupling cap works as a high-pass filter. With an 8 ohm load (speaker), the corner frequency is about 90Hz.

With the diode/resistor network following the cap, it's seeing a much higher resistance following the cap. A 220 uF cap followed by higher impedances would have an effective corner frequency nearly 0 Hz. It's not going to rise above 1 Hz until it's exceeded 700 ohms or so. I'd expect the effect to be somewhat "farty" as a result... A cutoff of around 50-80 Hz would be better.

Something like 0.1 uF might sound better... Or add an additional resistor after the cap to set the filter frequency before the clipping circuit. You can play with RC filter settings here... (0.022 uf / 150K combo would work.)

author
Undermig (author)2009-11-11

yo dude do you use a cuircuit board or you dont?

author
scubaluke (author)2009-10-22

alright ive got her all put together nice and good, but im having the same problem as 91chevywt. the switch just seems to double the volume, clean, and loud. so i guess its running through the amp chip but then not through the diodes, so what might be causing this?