Hawes Mechanical Television Archive by James T. Hawes, AA9DT
Build a Fuzzbox, Part 1

Fuzzboxes you can make

A vintage circuit that would give you a tone like Jimi Hendrix and Jorma Kaukonen: What would you pay for such a circuit? $200? $300? $1,000? Now you can build this circuit yourself. Use common, but top-quality parts, and pay $100 or less. The "or less" depends solely on your junkbox and your skill.


Real McCoy. Analog fuzz sounds different because it is different. When you want an analog effect, don't make do with a digital fake. Go with a real fuzzbox: Then you're back to simple construction and sweet sound.

But the cost! Not to worry. The price can be much less than the cost of a factory unit or even a kit.

Benefits. This version of the Dallas Arbiter fuzzbox offers many advantages over other versions. Modern, silicon transistors make the unit more reliable than the original germanium devices. The parts are easy to find, and we help with sources. Our Troubleshooting & Mods page helps you to adjust the tone to your need. The effect circuit fits onto a little piece of perfboard. We explain perfboard construction, because it differs from other methods. Why perfboard? Because it's inexpensive. Because it's the best way to achieve an effect that's both reliable and serviceable. Consider these perfboard facts...

  • Only perfboard projects can adapt to many shapes of devices, such as axial and radial-mount capacitors.

  • Only perfboard projects allow for frequent mods without the risk of damaging foils.

  • Only perfboard projects involve you in the circuit design. Building this perfboard project helps you to build and understand other projects. As you build, you're not just assembling. You're thinking about relationships between parts.

I built this fuzzbox for my nephew Jonathan who had then just joined a garage band. (His brother Jason was the drummer.)


NPN swap & input resistor. My circuit uses NPN transistors instead of the PNP devices in the original Fuzz Face. The NPN swap is an easy and worthwhile change to make. More general-purpose NPN devices than PNP devices will work in this circuit. Besides, most people relate better to NPN operation than to PNP operation. There's no big secret to the conversion. You flip the battery and then you reverse all other polarized devices. Done. I've also added one resistor to the classic design. The one-megohm pulldown resistor at the base of transistor Q1 reduces noise.

Depend on silicon. The transistors are silicon. I've heard that "silicon transistors have too much gain for this circuit." This statement is illogical. Thousands of different silicon devices exist. Among them are low-gain parts. Besides, the device doesn't necessarily determine gain. The circuit has a great effect on gain. Later, I'll explain more about the circuit.

To avoid gain problems, I hand-picked two transistors from my stock of old devices. (These devices come from Dayton Hamvention. My old stock consists of mostly "pull-outs" from old equipment.) According to my homemade beta meter, the transistors that I chose had gains around 100. The original germanium devices had these gains: Q1, 70. Q2, 120. On gain, I'd say that I'm in the ballpark.

Equivalent parts

You can use many general-purpose, small signal transistor types: 2N2222A, PN2222A, 2N3904, 2N4401, 2N5089, BC108, BC109C or many others. Though these transistors have gains of around 200, circuit adjustments can tame the angry silicon beasts. When I last checked, you could buy several fuzzbox-compatible transistors at All Electronics...

Just a few compatible transistors
MPSA06 (Gain of about 100.) Price is right! 34¢ each, including shipping (in 11-2015)
2N2222A, PN2222A, PN3846, 2N3904, 2N4124, 2N4400, 2N5772, MPS3704, MPSA20 (Gain of about 200) 10 to 20¢ each

Fuzzbox Schematic

Schematic: Fuzzbox with 
       NPN, silicon transistors. Easy to build. Battery-powered. Radio Shack stocks most parts.

Photo: Closeup of fuzzbox

Parts list

B1 Battery, 9-volt, alkaline or long-life transistor type
C1 Capacitor, 2.2 μF, electrolytic
C2 Capacitor, 20 μF, electrolytic
C3 Capacitor, 0.1 μF, poly film
J1 Jack, input, stereo 1/4-inch phone
J2 Jack, output, mono 1/4-inch phone
Q1, Q2 NPN, small-signal transistor: 2N2222A, 2N3904, PN2222A, 2N4401, etc. or hand-picked device
R1 Resistor, 1M, 1/4-watt, 5%*
R2 Resistor, 33K, 1/4-watt, 5%*
R3 Resistor, 330Ω, 1/4-watt, 5%*
R4 Resistor, 100K, 1/4-watt, 5%*
R5 Resistor, 8.2K, 1/4-watt, 5%*
S1 Switch, DPDT, toggle pushbutton (Carling®; Mouser #691-64112220)
VR1 Pot, "Fuzz," 1K, miniature, linear taper (Mouser #31-1000F-1K)
VR2 Pot, "Volume," 500K, miniature, audio taper (Mouser #31-JA505-F)
Misc. Case, cast aluminum. Knobs, small, set-screw type; for quarter-inch pots. Paint. Decal, printable. Wire, stranded hookup type. Wire, solid bus type. Perfboard. Studs, perfboard type. Hardware, 6-32. Standoffs, mounting. Clamp, metal battery. Pen, lacquer marker.
*RESISTOR TYPE. For the "original sound," use carbon composition or carbon film resistors. For low-noise applications, use metal-film resistors.

Switch wiring

Schematic: How to 
         wire the DPDT switch.

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WARNING. This is your project. Your achievement is entirely yours. I assume no responsibility for your success in using methods on these pages. If you fail, the same is true. I neither make nor imply any warranty. I don't guarantee the accuracy or effectiveness of these methods. Parts, skill and assembly methods vary. So will your results. Proceed at your own risk.

WARNING. Electronic projects can pose hazards. Soldering irons can burn you. Chassis paint and solder are poisons. Even with battery projects, wiring mistakes can start fires. If the schematics and descriptions on this page baffle you, this project is too advanced. Try something else. Again, damages, injuries and errors are your responsibility. — The Webmaster

Copyright © 2009 by James T. Hawes. All rights reserved.

•URL: http://www.hawestv.com/amp_projects/fuzzbox/fuzz1.htmWebmaster: James T. Hawes
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