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)
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 />
You say that &quot;Distortion is the clipping of sound waves.&quot; <br><br>That's only one type. <br><br>Any departure from the original signal is distortion.
&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