About Me:

Hello, I’m Cody Carter, a Computer Engineering student at Louisiana State University. My passion for technology began at a young age when I would tinker on various projects around the house with my dad. The moment he taught me how to use a soldering iron to fix a trailer, I was hooked. This sparked my curiosity, and I quickly dove into YouTube tutorials, discovering the endless possibilities of electronics. Since then, I’ve been driven by a desire to learn and innovate, constantly experimenting with new ways to solve problems through technology and programming.

Outside of my schooling and job, I am always looking for ways to make my life easier with technology and fusing my love of music and guitar with technology. In this case, I wanted to evaluate and construct the design of the classic Dallas Rangemaster guitar pedal to add modifications and reconstruct with modern components in a easy to follow format. 

About:

The Dallas Rangemaster Treble Booster pedal was a pedal first produced in 1965 by Dallas Musical Ltd. The intended purpose of this pedal is to add treble back to amps popular amps the time including the Vox AC30 or Marshall JTM45 that is lost due to overdrive or humbuckers. The result was a characteristic distortion and color change that suited the likes of Black Sabbath, Eric Clapton, Ritchie Blackmore, and countless more guitarists through the decades.

The Dallas Rangemaster was originally designed with germanium PNP transistors because that was most used at the time. Though these germaniums are sensitive to heat, humidity, and other issues that made the pedal sound different or not work altogether. Also, the original Dallas Rangemaster is considered one of the rarest pedals due to high demand and the very limited production. As a result, many modern clones were made of this pedal with more modern components that are cheaper and more reliable. Germanium tends to have a warmer rounder tone with less aggressive fuzz, with silicon having a more aggressive fuzz sound with higher gain. Both transistor materials have their pros and cons and are sought after for a certain desired tone, though may require slightly different circuits for best performance.

Parts List

Originally the Dallas Rangemaster incorporated PNP germanium transistors. This was because PNP germanium transistors were easier to make consistently and didn’t have any major leakage current like their NPN germanium counterpart. PNP was not an issue back then, since the pedal ran off a 9V battery. The problem comes from the standard center negative power supplies used for guitar pedals not being able to work with PNP without a major redesign of the circuit. This issue was fixed with NPN transistors being put in the circuit, making no difference sonically.

The design implemented in this repository is made with silicon NPN transistors as I wouldn’t have to worry about inconsistent germanium transistors and anything power supply wise to be able to run the pedal. If you swapped power polarity on a PNP circuit to work with common pedal power supplies, it causes more noise, hiss, motorboating, and more issues. In the circuit design section there will be a additional MAX1044 circuit listed that will provide clean negative ground power for use with the original circuit.

Parts List:

This list is for the design I am going with for this pedal with pull down resistors, fuzz switch, and NPN silicon transistors

1 BC109C NPN Transistor (BC108C, BC109, BC183L, BC209C, 2n2222, 2n3904 are also commonly used)

2 5nF capacitor

1 10nF capacitor

2 47µF electrolytic capacitors

1 470KΩ resistor

1 68kΩ resistor

1 3.9KΩ resistor

2 1MΩ resistors

1 10kΩ Logarithmic Potentiometer

2 1/4" female guitar jacks

Circuit Diagrams and Common Mods

NPN Dallas Rangemaster Original circuit with NPN transistors

NPN Dallas Rangemaster with Pull Down Resistors and Fuzz Switch

Added pull down resistors and input capacitor switch

Pull down resistors added for reduced electric noise and useability with other pedals

The switching of input capacitors changes the frequency response of the pedal, making the Rangemaster more versatile. This is the same mod used in Tony Iommi of Black Sabbath's Rangemaster pedal

PNP Dallas Rangemaster Circuit

Original circuit with PNP Transistors running off of a 9V battery

MAX1044 Power Supply Mod

If wanting to use the PNP circuit with a modern pedal power supply, use this mod to supply clean isolated power needed for this circuit to run properly

Circuit Board Design

Fully rendered 3D model of the circuit board to be installed in the Rangemaster pedal

Closing Remarks

As you can see, the Rangemaster's iconic tone can be created and modified with a very simple circuit without paying a huge premium for an original model. There are countless more mods out there on the internet done by different companies and guitarists alike to add something new to it's sound. As I test and discover new mods, I will update the repository as necessary.

I appreciate how PCBWay has provided professional solutions to students and electronics enthusiasts, and I believe that their sponsorship would be essential to easy and reliable construction of Dallas Rangemaster. It would be an honor to share the results with the PCBWay community and contribute my project to their platform, as well as inspire more hobbyists like me to experiment with electronics.

Whether it’s school or personal projects, I’m driven by the desire to create technology that makes a difference and improve my skills. If you’re interested in collaborating or discussing anything further, lets connect to talk about it.

Thank you very much for your time and consideration!

• diy
• guitar
• pedal
• guitar pedal