Photo 10: You can make sense of many stompbox schematics if you learn half a dozen symbols.
Working with schematics. A schematic is simply a graphic representation of a circuit. Schematics can look intimidating, but it doesn’t take long to learn the basic symbols. Photo 10 shows the schematic for this project. The build guide PDF discusses it in detail, but here’s a quick intro:
· Schematics are usually arranged with the power connection at the top, ground connections at the bottom, input to the left, and output to the right.
· The zigzag lines depict resistors.
· The potentiometer symbol is like the resistor symbol, but with an added arrow to indicate the middle lug.
· Parallel lines symbolize non-polarized capacitors.
· The electrolytic cap symbol adds a curved line and a plus sign to indicate polarity.
· The diode symbol includes a triangle and a line. The side with the line is the negative terminal. The LED symbol adds arrows representing emitted light.
· Like most circuits, this one includes many connections to ground. We could connect them all with lines in the schematic, but the schematic is easier on the eye is we indicate ground connections with a simple symbol: the downward-facing triangle.
Don’t sweat it if you’re still confused—it’s covered extensively in the build guide.
Mods of the gods. Sure, you might be a beginning builder, but chances are you have strong tastes when it comes to guitar sound. It’s never too early to modify projects to better meet your musical needs and personal style. In fact, you’ll be doing just that within the first few minutes. Even in this simple circuit, small modifications can dramatically alter the effect’s sound and response.
Your modding experiments will focus on three areas:
1. You’ll try different values for the input capacitor (labeled C1 in Photo 10). This part acts as a high-pass filter, removing lows. But the result isn’t quite like, say, turning down the bass knob on your amp, or using EQ to remove lows from a recording. Here at the front of the circuit, slight component variations alter the effect’s fundamental character.
2. You’ll audition three different transistors (the part labeled Q1 in Photo 10). This component defines the circuit’s gain. You can make this an understated overdrive or an angry chunk machine.
3. You’ll experiment with different combinations of clipping diodes (parts D1 and D2 in Photo 10). The result can range from soft, warm distortion to razor-edged sizzle.
DIY not? Remember, this project isn’t just about building a cool distortion pedal. The goal is learning the “whys” as well as the “hows” so you can a) apply these techniques to any project, and b) alter circuits to taste. I hope you find the process fun and informative, and that when the smoke clears—hee hee—you have an inspiring musical tool. For best results, maintain your patience and sense of humor, and don’t freak out when you hit the inevitable hurdles.
There’s much more info in the PDF build guide, including additional resources and troubleshooting tips. Download it if you dare!
To download the entire build guide in an easy-to-use PDF, click here.
And in case you missed it, watch the video demo of the PG Distortion: