Ever wanted to give your guitar or bass that overdriven tube amp sound? This is how to make a DIY overdrive/distortion sound for under $10 that sounds as good as the $50 ones. If that money difference is not good enough for you, you can change this effect to exactly how you want it, whether you want thrash-metal distortion or just a light overdrive. It is very easy to make, so if you have never soldered in your life, this is still for you.

This was inspired by https://www.instructables.com/id/Simple-overdrive-effect-pedal/, however I could not get it to work right so I did some research and made my own. The similarities are there because I made this (mostly) from parts I had purchased for his project.

Feel free to make your own improved version and post the instructable, but it would be great if you could put a link back here somewhere in the 'ible. Thanks!

Stay tuned for a video of my playing it.

Step 1: When to Use Distortion

If you already know what distortion is and have used it before, skip this step.

There is nothing I hate more when a beginner, or even advanced guitarist steps out with the distortion cranked all the way up and starts playing chords. But you may like that. If you do, ignore my opinions.

If you have no idea what distortion is, start out by listing to a few songs.

Compare the song Jimmy Olsen's Blues by the Spin Doctors to Master of Puppets by Metallica. As you can probably hear, Jimmy Olsen's Blues has a very clean, well, bluesy sound, while Master of puppets has a rough, cutting sound. If you are still have trouble, listen to the song Around the World by the Red Hot Chili Peppers. That intro is a highly distorted bass, played by the master Flea. If you want, compare that to Blues For Mingus by Stanley Clarke. That is clean bass.

Now that you know what distortion sounds like, you should learn when to use it and how much to use.

In my own opinion, even if you are playing metal, never turn the distortion up so high that you can barely hear the chords you are playing. There is another no-no. High distortion with chords-too loud. In my opinion it sounds great with individual notes, but not with chords. But feel free to do whatever you like.

If you play jazz, your band-mates might not like the idea of you playing screaming distorted riffs, so go light on the distortion for jazz. Blues is the same way, but if you put a little bit of "tube scream" it sounds great. But as I said before, do whatever you like.

For all you bass players like me, distortion is even more fun! I personally like a medium amount of distortion, which this design makes. If you like more or less, by the end of the instructable, you will know how to alter it to your liking.

And lastly, other than the "rough" scream of distortion, what else will you notice?

First of all, distortion has some MEAN sustain... the notes keep ringing and ringing until you mute them. The other large thing is, HARMONICS. You can play harmonics with distortion incredibly easily, and they are as loud as the note. They have many different harmonics in them too. Great sound if you like harmonics like I do.

Step 2: What Is Distortion?

If you know what distortion is, skip this step.

So, now that you know what distortion sounds like, what is it?

Distortion is the clipping of sound waves, or AC at whatever frequency the note you are playing is.

The term "clipping" refers to the tips of each wave "clipped" off. There are several ways to go about doing this, but I went with the good ol' diode clipping method.

A diode looks like a resistor, but is not very similar. It lets a certain amount of voltage (called forward voltage drop) go past it, while the rest is sent to ground. For example, if you had a hose, imagine a valve that only lets 1 psi go by, while the rest is diverted to a different hose. Back to resistors; that resistor would have a forward voltage drop of 1. My design calls for a red LED, which has a forward voltage drop of ~2 and two 1n914 diodes with a forward voltage drop of ~.7 each (more like .65-.68). They are set up in such a way to let 1.2 -V and 2 +V through. That means if your signal was at 4 volts, you would be clipping 2.8 volts off of the -V and 2 off of the +V. That is without resistors and capacitors. See the simulated picture below for an example.

As you can see in the next picture, there is both soft and hard clipping. They will both distort the sound, but hard clipping is more metallic (think heavy metal music) while soft clipping sounds more like a tube amp turned up too high. They term soft and hard refer to the sharpness of the clipping. Soft is more curved, while hard has much more of an angle. See the image for a visual.

Step 3: What You Need

Parts list (for my method):

-Two 9-Volt batteries
-Four 100 ohm resistors
-One LM741 op amp
-One 1K ohm resistor (1000 ohm)
-One .1 uF capacitor (any type)
-Two 4.7K ohm resistors (4700 ohm)
-Two 1N914 switching diodes
-One red LED
-A project case
-Two mono 1/4" (6.3mm) female jacks
-One DPDT switch (two way 6 pin)
-One on/off switch
-Perf board (with copper rings on bottom)
-Thin wire
-Soldering iron
-Two 9 volt battery holders (just take the tops off of two dead 9 volt batteries, the batteries will fit into them perfectly)

I also suggest getting a solder sucker and some soldering braid. Very useful stuff!

All of the above can be purchased at Radio Shack, so no need to hunt around. The total price should be around $10, unless you need a soldering iron. Those usually run about $10-$20.

Step 4: The Schematics

Here is the schematic for the actual distortion. After is a schematic of how I wired the switches. If they are too small to read, here are links to larger ones:

If you don't know how to read schematics, don't worry! Just pay attention to the notes on the images. You would be better off looking up how to read schematics, though, just to be safe.

Pay attention to the back of the LM741 package for the terminal numbers, if you get those wrong you could cook the amp. All the numbers on the schematic are right, just placement is funny, because the amp is a rectangle, while the schematic amp is a triangle. Don't ask my why... I didn't invent schematics.

When grounding, solder a stripped wire across most of the perf board, and when you ground something, just attach it to that. That will count as your ground, no need to solder it to the case!

NOTE: The second schematic is just how to wire the switches to the op amp, so you will still have to use the resistors from the first schematic. I made two different schematics because I knew people would want to use their own switch layout. This way they can see how the switches work.

For the 1/4" jacks, there should be two terminals coming off across from each other. If you look carefully, you can see that one is attached to the long contact while the other is attached to the entrance to the jack. Connect the one at the entrance to ground, and the other pin to where the schematic says (in=pin 2 out=pin 6)

Step 5: How to Solder

If you are experienced with electronics, skip this step.

If you have never done something like this before, here are some tips that I learned to do (and not to do).

-Use a small piece of perf board. I fit this entire circuit (without the switches) onto about a 1X3 inch piece easily.
-Lay the circuit out on the piece like it is on the schematic. It will be reversed on the bottom, but I'm sure you can figure it out.
-When soldering, NEVER touch the solder to the soldering iron. Hold the iron to the wire and let it heat up. Then touch the solder to the wire, and let it be wicked up and down for a good connection.
-For this circuit, you can attach the terminals directly to each other instead of wiring a tiny gap. Just bend and solder. Be careful though!
-Attach all grounds to one copper wire soldered to the perf board. It makes everything ALOT easier.
-Make sure your grounds are connected very well or else you will get a loud buzz.
-Get some desoldering braid. That stuff is very useful! I couldn't have done this project without it.

Practice, practice, PRACTICE! The op amp can be cooked if you hold the iron on it for very long. Try cutting a little piece of perf board and solder wires to it and then desolder them. There is nothing worse than going through the entire process to find out the project doesn't work. I know. I did that twice (different designs).

Look at the second picture for what the soldering should look like.

Step 6: Connect Everything/the Box

Connect everything according the the schematics. Once you are done, drill holes in the box and stick everything in there. I just taped everything down with electrical tape, including the batteries. And there you have it! Your new distortion effect! Keep reading if you want to learn how to adjust it to your liking.

Step 7: Making Your Own

As you know, more diodes is less clipping, less is more. You can play around with those, or you can use a simulator (recommended).

Here is the simulator I used: http://www.falstad.com/circuit/. Let it launch and play around with it. If you want to import my design, press file>import, download the text file attached to this page, and enter the code from the file into the import box. You can then play around with it and see what the waves will look like coming out.

Play with the resistors, capacitors, and as many other things as you can think of. Since you know what clipping looks like in the wave, you know what to aim for. If you want others to look at your design before you build it, press file>export and copy and past the code into a comment below.

Some useful info:
-I suggest that you keep the input at 41 hertz because it is a note on the bass (a low E) and is easy to see because it is such a big wave.
-The average output for a bass or guitar is around .1-1 volts, so I used .325.
-The gain for the op amp is based on the resistor circuit underneath it. The actual equation for output voltage is Vin*(1+R2/R1). Since there are 4 of what would be R1, you would calculate the overall resistance, which is 133 ohms. R2 is 1K. R1s are all 100 ohms.
-The equation for resistors in series is R=R1+R2+R3 etc...
-The equation for resistors in parallel (like the 3 pictured on top of each other) is 1/(R1/1+R2/1+R3/1 etc...). In the case of this it is 33 ohms, then you add the 100 for the one resistor in series. That is 133.
-The LED should not go over 25 MW @ <2 volts or else it can explode. It smells really bad when it does.
-The LED must be at 15-20 MW to light up, and should not go over 2 volts.

If you do make one, though, post an instructable! Tell everyone how to made it, but it would be great if you could put a link back to this instructable if you used it much. Thanks!

Good luck!
Where did you get your case? And please could you tell me what a One DPDT switch (two way 6 pin) means. I'm new to this
I got my case at radioshack.<br><br>And, http://www.boiseastro.org/images/switch-contacts.jpg<br><br>The internet is a powerful tool.
RADIO SHACK rips you off, goto mouser or tayda electronics or ebay.....
Thank you. This is very helpful.
Do we have to use 2 9v batteries??
No, but you need to add some resistors and a capacitor to get it to work off 1 9v battery, Ask me if you want to know how.
No. He used 2 batteries because he needs to generate a negative voltage. A resistor divider works but the voltage is lower.
For a much quieter (less hiss) pedal, use an ne5534 instead of a 741, it's a bit more expensive but a much better op-amp for audio circuits and has exactly the same connections (pin-out)
uhhmmm...he designed it for an acoustic guitar, ... didn't mention about how was the distortion????????
Hey, I know that this is a relatively old instructable, but I'll still comment this.<br>I still dont make it yet, but i've been messing with the simulator for a while.<br>I've attached a potenciometer and removed a couple of resistances, but i think this should go well.<br>The import code is here: http://www.pasteall.org/23731/ (dont mind the numbers on the left side).<br><br>But my question is, will it really work?
hey I'm not really sure how does the DPDT switch works, in one position you're sending the guitar input to the opamp, but in the other position are you sending the guitar's input to the opamp's output? I know it's a stupid question but I've never used that type of switch and was just wondering =P
Its a switch that when it is pushed in once, it will send the signal through one wire, pushed a second time it will send through another wire. on this, on the first push it will just go directly to the output. pushed again, it will have to go through the circuit first before going to the output.
its a bypass switch<br />
&nbsp;mine didn't worked at all... but the LED is working...
mine works but the LED won't ha
I don't know why but if i turn the sound off on my guitar the pedal picks up radio, specifically around 98 fm.
what are the sizes of the resistors is it 1/4?
what voltage for the&nbsp;&nbsp; .1 uF capacitor <br /> is 63v okay?<br />
What are the wattage on the resistors?
Pretty much any wattage should work. We're not talking that big powers there that you should worry about the wattage..<br />
Im guessing just standard 1/4 watt metal film resistors
&nbsp;hey. i was wondering if its a hard thing to replace the batteries with a &nbsp;9v adaptor?<br /> <br /> thanks<br />
&nbsp;never tried it, but I don't see why it wouldn't work...
&nbsp;sorry to bother again, but i have a ton of questions about this project(i really like it) so i was wondering, could you make this into a true bypass? meaning there would be no need for the bypass/distortion switch? and also, where would i wire pots if i wanted let's say a tone control? and also i'd like to hear what it sounds like. and also, what should i substitute(with what) if i wanted a beefier sound?. and last but not least, do you think it would be possible to make this solderless with a perfboard??<br /> <br /> &nbsp;&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;i'm sorry for having so much question, but i'm really interested in this. hope to hear from you soon, sick_nixon<br />
&nbsp;it'd look way nicer if you would place the jacks on the side instead of on top. is there a technical reason why you didn't??
&nbsp;yeah it probably would have, I just had it that way because I thought it would look different. I can't think of any other reason why I might have done it... it's been a while now.
instead of messing with the bits could you just attach a knob i between the batteries and the rest to control distortion levels?
i guess so, but i don't know if i would do that... instead of controlling the actual gain you're limiting power... in which case you lose battery life (i would think). I figure since the chip is built to have gain control, there are probably other reasons too. but hey... try it out and tell me how it works... i'm gonna get a breadbox pcb... the ones where you don't have to solder and then i'll try stuff like that. even though the simulator works, you can't beat the real thing.
I'm a n00b at reading schematics, is the switch on there? Else whys, where would it go? Thanks! Hope this isn't too juvenile a question. Haha.
what could you add or take out to make this have a "thrash metal sound" (I play alot of Metallica) and where would you place a potentiometer so that it just affects the overall volume? Thank you in advance! Great i'ble, Fave'd +5 By the way.
If you add a pot right after the input, it would control the volume, right?
No, that would control distortion (limits sound coming from guitar, then in turn limits amount of signal that can be boosted, in turn limits clipping) try right after the diodes. I might be wrong though... run everything through the simulator for a better answer
Wow! I guess I forgot to check my comments. If you still want to build it, or take it apart, just take the resistors away from around the diodes (that little box of resistors on the schematic). That will give it a much harsher sound. Good luck! And remember, throw a resistor on the end so you don't blow your speakers!
What 'little box of resistors'? I'm dumb. Also, how many ohms should I use between output and ground to drop the volume a bit (you said it gets very loud?)
it starts the square of diodes... right above the diodes... and as far as ohms, I have no idea. I never put the resistors in, but try it out in the simulator until you get an output of about what your input is. That way, when switching, the volume stays the same.
haha thank you, buy its built now, and i hot glued everything in place because i got the wrong kind of perfboard... but i did get it working by adding some pots in the right place...
and also, is there any way to wire in a switch so it boosts the volume without having to turn up the potentiometer, I know that it would somehow have to go to a smaller resistor somewhere, but Im not sure exactly how.
Now, my little goal is to construct an electric Triangle. It would be cool to have a distortion box like this to hook up to it, but as you know the frequency of the sound from a triangle is far higher. What resistors should I put where to make sure i don't blow the circuit?
I think that that's usually what op stands for in that context.
hi! thanks for this! could you please post the diagrams again? the links are dead and i ain't pro to see the second one here...
It's a very helpful instructable, thanks! The only problem I have is that I am very new to working with electronics and I never had to work with ground in my principles of engineering class (we just dabbled into electrical engineering with solderless breadboards). I noticed that you mentioned to connect all grounds to a copper wire. Do you think you could explain that a bit more? Like, how to connect? Should it be along the entire wire? Where that wire goes? Like I said, I'm a newbie but so far I've been learning a lot from this instructable. Thanks!
Hah hah hah, I don't quite have the theory down pat yet, as grounding I found is really really hard to understand. I'm 15 and haven't even taken principles of engineering yet, so let's see what I can do. Just solder a stripped copper wire across the board with clean connections, and then take each wire that needs grounding and solder that to any point on the copper wire. Ground is just a 0 voltage reference point for circuits. I guess that reference point has to be a complete circuit, though. I guess circuits base their output on 0 voltage, however since there is no way of processing in a basic circuit, it needs something to base the output signal off of. Check out wikipedia for a much better, more complicated definition.
Thanks ! now i know the jack input problem but, when at the output, connect at the entrance or the pin ? (my instinct says at the entrance) :D
Yes, ground is entrance... if I understand what you're saying. Think of it this way... guitar cords are mono. The tip has the signal, while everything from that little black line down is the ground. That means, ground anything touching the ground on the cord.
thanks for the reply then, now i only have one question... Where is the ground? Are the ground is positive side of the batteries ?
well i built it, but it doesnt work quite right, all it does is buzzes freaking loud, i tried messing with the grounds and everything, any suggestions??
Then you have cold solder joints or you didnt follow the schematic right. I built this and it works fine, work on you soldering a bit. -Buster
ya, i think i followed the schematic wrong, because i wired in some pots and it fixed the problem and lets me change the amount of sustain i have along with the amount of distortion, the dpdt switch doesnt work right though, so thats my next task to figure out :-/ but overall im happy with the project.

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