TUTORIAL El Sol Distortion

BuddytheReow

Breadboard Baker
To kick off part of the "build along" series for The Test Kitchen I decided to pick a rather simple circuit with a low parts count. For those of you new to breadboarding this will be a great transition from the "Intro to Schematic Reading" to actual building. There will be some hand holding here and that is the purpose of this initial "Build Along". Below is the schematic and I will walk you through step by step to a successful build. I will not talk about the offboard wiring since most of us have different methods (protoboard, test box, auditorium, etc.)

The build document for this circuit can be found here.

Here is the schematic for the El Sol. I am removing r100 and the LED since that's only for use to know the circuit has power. This is comprised of 2 LM286 chips, 2 resistors, 1 nonpolarized capacitor, 4 electrolytic capacitors, and 1 potentiometer. I will break down with explanations and pictures how to wire this up. This is merely the process that I chose to use in putting this circuit together. There really is no wrong was to wire this up. Similar to populating a PCB, there really is no wrong way to do so, but there are general guidelines to make it a bit easier to build.
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My breadboard is the full size 830 point one and some of you may only have the half sized one. That's ok. Just make your layout a bit more compact than mine. I have spread mine out a bit to make a better picture. The first thing I like to do while breadboarding is blocking off the different areas on the board to work with. I will make my power section the top right corner and marked it off with C100 and making the negative lead (it will be the smaller lead and clearly marked with a "-" on the body) into ground which will be the BLUE strip on my board. This is pretty much the full power section of this circuit. The capacitor is merely to act as a filter to give you "cleaner" power. I will put the LM386 chips about a third of the way from the top and bottoms.



As good practice so I don't forget further down the road for any build I do I add my power jumper cables. A cable each (power and ground) for my power to go into the board itself, a jumper to connect both sides of the board, and a cable to connect the power into C100.
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Now let's look at the grounding of the two chips. Pins 2 and 4 of each IC should be connected to ground. ICs are usually marked with pin 1 on the top left and count off counterclockwise. The circle or notch should be facing north. Let's get those bad boys hooked up.


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Now let's connect our positive voltage to the ICs. Vcc in the schematic goes from the positive end of C100 into pin 6 of each IC. You will need 2 wires for this.

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Let's take a look at the input section of this circuit.

I chose a yellow cable as my signal input, but you can use whatever color you'd like. Just remember that that color is you input. Pick a spot toward the top left of you board and plug it in. 2 other components also need to go into that same row: a 1m resistor and a 10uf electrolytic capacitor. Place one lead of the resistor into the input row and the other lead into the ground section (blue for me). The short capacitor lead ("-") needs to go into the input row on your board and the longer lead needs to go into pin 3 of the first IC.
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Now we will install C2. The long lead goes into Pin 1 and the short end goes into pin 8. To keep things cleaner and to reduce noise (don't overlap parts) I have put the positive lead into pin 1 and the negative/short lead a few rows above pin 8. I jumpered from this row into pin 8.
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Now we need to start connecting IC 1 to IC 2. This is done via C4, C5, and R2. I place a red jumper cable from pin 5 to about a third of the way down to the next IC. From here the large lead of C4 is connected to the jumper and the short lead goes a few rows down. R2 should be placed in this row and go down a few more rows to help close the gap between the 2 ICs. One lead of C5 goes into the "out" of this resistor and the other to ground (blue)

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A jumper should be added from the row where R2 and C5 meet into pin 3 of the second IC.

We are almost done!

Out of pin 5 of the second IC I place the long lead of C3 and the short end a few rows down. The pic doesn't look like it with the red jumper blocking, but trust me. That's what I did.

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Let's talk about potentiometers for a minute. There are many ways to connect your pot to a breadboard. The simplest, but most destructive method is to shove a PCB mount pot directly into your breadboad. Yes, this will work but you will be potentially damaging your breadboard in future builds. Another way would be to solder some solid core wire to each pin with the other end going into the board. You could also buy alligator clips with a jumper pin on one end of them and connect the clip to the pot. The method I use is to whip up a daughter board with terminal blocks, header pins, and some stripboard. I can change the pots pretty quickly and have their corresponding lugs connected via the header pins directly in front. You may use any method you'd like but keep in mind that each method has a cost (potential damage to your breadboard, wire/solder, or other time/resources).

Back to the build...

Pin 3 of your volume pot (A100k) connects to the out/negative lead of C4 (my black wire), pin 1 of the pot to ground (my white wire), and pin 2 (my blue wire) is your output to the output jack/amp.


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Voila! You have now completed a test version of the EL Sol Distortion circuit from PedalPCB.com!!!! Don't forget to watch the volume on this build: it's really loud compared to all the other circuits! Any questions or comments please don't hesitate to reply below.

BuddyTheReow
 
Well done. Did it work the first time you powered it up? ;)
Yea. Since this is my first time "teaching" I was really hoping I didn't have to troubleshoot such a simple build. Luckily it fired up the first time. When and if I want to share some of the more complex builds with the community here that will be a nail biter as I'm putting it together and taking pics...don't want to share a build that doesn't work!
 
Thanks for this tutorial! I feel like I learned a lot in just 30 minutes starting from zero breadboarding knowledge.

I followed along and built it three times now on my Protoboard. Each time I'm getting that gated LM386 distortion as expected, but it's with very low output volume and the pot does little. I started unplugging jumpers to see where the problem is, and interestingly the sound is the same even when I unplug the power jumper and/or pin 3. It's likely a problem with my soldering on the Protoboard, that's going to be a nightmare.

As an aside, I omitted the 5V and 3.3V chips on the Protoboard since I don't want to mess around with SMD at the moment, would that have any effect on the rest of the rest of the Protoboard circuit?
 
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