FUZZ DUO

VINTAGE FUZZ

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SCHEMATIC (PDF)

This pedal is discontinued. Please check our dealers or our Reverb store for any remaining stock.

Schematic created by BuggFX

The FUZZ DUO lets you switch between low-gain germanium & high-gain silicon transistors, or use a combination of both to create your own signature fuzz tone. The BIAS control lets you dial in that perfect sweet spot, and the revised FILTER control balances between separate bass & treble filters. The FUZZ DUO uses hand-selected germanium & silicon transistors, and works great when daisy-chained on a power supply.

Click the different parts of the pedal to learn more.

Demos

How It Works

Features

Tech Specs

Story

Older

Versions

FUZZ DUO BLOCK DIAGRAM

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FEATURES & CONSTRUCTION

TrueSoft  Bypass

Discrete Circuitry

Noise Filtering

DualMode Switching

We combine durable true bypass relay switching with an effect-side FET switch for pure and smooth switching.

With fuzz pedals, simple is often best. The Fuzz Duo & Solo are both built on a 2-transistor, all-discrete circuit.

We added extra layers of noise filtering in the Fuzz Duo and Fuzz Solo families, to make them as quiet as possible.

DualMode Switching can convert the footswitch into momentary operation.

To use, wait 5 seconds, then press the sequence tap+tap+hold until LED flashes.

USA Made PCBs

Our circuit boards are made in the USA by Advanced Circuits (large PCB runs) or OSH Park (small PCB runs).

WIMA Capacitors

WIMA is a world leader in film capacitor technology. We use 5% tolerance for consistent tone from pedal to pedal.

All VFE Pedals are built with these quality components and features:

 

- Rugged diecast aluminum enclosures

- TrueSoft + DualMode true bypass switching

- Industrial-grade Carling switches & Neutrik audio jacks

- Alpha pots soldered directly to PCB

- 5% WIMA film capacitors & 1% metal film resistors

- Cardas Audio ultra-pure, eutectic silver solder

- P3 system phantom-power compatible

- Built by hand in Puyallup, WA, USA

- 1 year warranty on parts & labor

DIMENSIONS:

Enclosure dimensions: 2.37"W x 4.37"L x 1.16"H  (60 x 111 x 29mm)

With knobs & jacks: 2.6"W x 4.4"L x 2.1"H  (66 x 111 x 53mm)

 

POWER:

Standard 2.1mm, negative-tip 9V to 18V power supply or 9V battery.

 

INPUT IMPEDANCE:

Varies by transistor #1 (germanium = low impedance)

 

CURRENT DRAW:

~10ma continous

+30ma surge for 4ms during on/off switching

BY THE NUMBERS:

7 RESISTORS

10 CAPACITORS
4 INDUCTORS

6 TRANSISTORS

5 DIODES

0 OP AMPS

2 INTEGRATED CIRCUITS
6 POTENTIOMETERS
4 SWITCHES

3 JACKS
2 CIRCUIT BOARDS

HOW THE FUZZ DUO CAME TO BE

THE STORY

Anyone who's experimented with simple, transistor-based fuzz circuits knows how much the transistors you select can impact the tone. In true VFE fashion, I wanted to build a fuzz pedal that let the user decide between various transistors. The very first prototype had a 3-way rotary switch to toggle between germanium, silicon, and hybrid fuzz tones.

 

Over the years the Fuzz Duo has undergone many small revisions to improve usability, lower noise, increase volume output, and most importantly increase the tonal flexibility of the FILTER knob, which is fundamental to getting the right frequency balance in the fuzz.

-- Peter Rutter, founder of VFE Pedals --

Here is the list of versions of the Fuzz Duo circuit:

 

#1 - The first one-off design used a large switch to toggle both pairs of transistors from germanium to silicon simultaneously. It was hand-wired point-to-point and included no tone controls.

 

#2 - The first PCB model separated the transistor switches, so you could create hybrid fuzz tones with both germanium and silicon transistors. A treble cut FILTER was added to the feedback loop. An internal FEEDBACK trimpot controlled the gain & bias range. OC140 germanium transistors were used in this version.

 

#3 - While the external controls did not change, the internal feature set and circuitry did change over time. Some revisions had internal DIP switches to adjust bass response, and a couple were even adapted to use PNP transistors. Various hand-selected transistors were used, based on tonal quality and availability.

 

Here is what is new in the current version:

- FILTER control has been updated for more tonal versatility, from bass boost to treble boost to mid hump EQs

- Extended range of BIAS control

- More natural and useful taper of FUZZ control

- Dual-Mode switching