48 Circuits or Less

By: Dominic Sciarrino | Stompbox Electronics | Last Updated: March 12th, 2026 Today, we’re peeling back the curtain on Passive RC Filters! With just one resistor and one capacitor, you can build a circuit that selectively filters specific frequencies from an audio signal. That circuit is a passive RC filter, and it is one of […]

By: Dominic Sciarrino | Stompbox Electronics | Last Updated: April 9th, 2026 Most guitar effects circuits run directly from a 9V supply with no voltage regulation required. The moment a digital component enters the design (i.e. a PT2399 echo processor, a microcontroller, a DSP chip) that changes. Digital ICs commonly require 5V or 3.3V, and

What is a Charge Pump? A charge pump is an integrated circuit (IC) that is used to convert from one voltage to another. As an example, let’s say you want to build a circuit that runs on +18Vdc, but you want to power it using a +9Vdc adapter. You can use a charge pump IC

What is a Charge Pump Inverter? A charge pump is an integrated circuit (IC) that is used to convert from one voltage to another. As an example, let’s say you want to build a circuit that runs on +18Vdc, but you want to power it using a +9Vdc adapter. You can use a charge pump

By: Dominic Sciarrino | Stompbox Electronics | Last Updated: March 22nd, 2026 Almost every guitar effects pedal ever made has one thing in common: an indicator LED that tells you whether the effect is engaged or bypassed. The indicator LED circuit is one resistor and one LED: the simplest circuit in this series. But get

Guitar pedal battery switching, DC power disconnect, and expression pedal wiring explained Introduction Switches: the most engaging electromechanical component! Available in all sorts of shapes, sizes, and configurations – switches give us the ability to interact with the electronic world. In this post, we’ll be covering a very particular type of switch technology that will

By: Dominic Sciarrino | Stompbox Electronics | Last Updated: March 22nd, 2026 Every component in a guitar effects pedal depends on a clean, stable DC voltage to function correctly. The power supply is where that voltage comes from, and understanding it from a design perspective is one of the most important foundations in effects pedal

By: Dominic Sciarrino | Stompbox Electronics | Last Published: February 27th, 2026 Introduction Plug in the wrong polarity power supply – even briefly – and the results can be immediate and expensive. Electrolytic capacitors fail catastrophically. ICs and transistors conduct in the wrong direction. Reverse voltage can destroy a circuit in seconds. The fix can

By: Dominic Sciarrino | Stompbox Electronics | Last Updated: February 26th, 2026 Introduction You’ve plugged a 9V power supply into a guitar pedal. But the circuit inside isn’t running 9 volts everywhere. Different stages need different voltages to operate correctly. A transistor amplifier stage needs a specific bias point. An op-amp needs a reference to

By: Dominic Sciarrino | Stompbox Electronics | Last Updated: February 25th, 2026 Introduction If you’ve ever built a true bypass pedal, you’ve probably heard a loud thump or pop the moment you engage the switch. It’s one of the most common problems in DIY pedal design, and it has a specific, well-understood cause … and