On one of my daily hunts for broken pedals, I stumbled upon this late 1966 Maestro FZ-1A enclosure that needed attention. The original pots were removed and replaced with jacks, and the original footswitch was replaced. I assume this was some sort of A/B switcher, but crudely made. Since I’ve never built or breadboarded an […]
Repair Room #23: Maestro Fuzz Tone FZ-1A Rebuild Read More »
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
Circuit 6 of 48: The Passive RC Filter Read More »
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
Circuit 9 of 48: The Linear Regulator Read More »
The PROTIS 1 sports a convenient potentiometer, or “pot,” interface for fast and easy breadboard wiring. In this post we’ll explore what this interface looks like and how to utilize it for building the circuits that require them. Preliminaries: Potentiometer Operation A basic potentiometer has three connection points. We will call them: Between Lug 1 and Lug 2
The Three Potentiometer Configurations for DIY Guitar Pedals Read More »
The PROTIS 1 Guitar Effects Development Board can be used for prototyping and testing out various DIY guitar effects circuits. This post provides an example circuit, the common Transistor Buffer, to highlight basic functionality offered by the PROTIS 1. In this post you will learn how to utilize the Power section and the Input/Output (I/O) connections. Get
Getting Started with the PROTIS 1: Transistor Buffer Read More »
One of the most important parts of building your DIY guitar pedal is figuring out how to apply power to your circuit. The required voltages are generally standardized across the industry as +18V, +12V, and (most commonly) +9V. All three of these voltage levels are supported by the PROTIS 1 development board. Other voltages are
Powering Your DIY Guitar Pedal Designs with the PROTIS 1 Read More »
In the flavorful 1960s Eric Clapton’s signature overdriven sound with John Mayall & the Bluesbreakers gave rise to the popularization of the Marshall 1962 model amplifier. Twenty years later, sharing the stage with notable hard rock and metal guitarists gave the 80s generation of guitar players a reason to notice the almighty Marshall JCM 800s;
The Marshall Tone Stacks: From Bluesbreaker to the JCMs Read More »
I had always heard about how there was a problem with certain versions of the MXR Carbon Copy, so I’ll admit there was a bit of excitement when I was approached with this repair. Basically, the pedal would work in bypass mode but did not turn on or pass signal when engaged. The indicator light
Repair Room #22: MXR Carbon Copy Repair Read More »
If you’re here, I’m sorry for your loss. The guitar pedal you once loved is now lost. It’s time to move on, and part of that is taking it out from the bottom of your closet and finding it a better home. eBay can help with that. Technicians and hobbyists are out there waiting to
How to List a Guitar Pedal for Parts/Repair on eBay (2024) Read More »
Is your Line 6 DL-4 not working? Before you decide to scrap it or sell it for parts, consider this troubleshooting guide. We’ll look at common problems with the Line 6 DL-4 Delay Modeler pedal, as well as common solutions to those problems. Hopefully stepping through this process will get you closer to a working
Line 6 DL-4 Not Working – Repair Guide Read More »
