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Overview
2017 Changes:
Reworked the layout for centralized I/O pads. Removed cap between Q3 collector and base (mostly not
needed).
This project is a silicon version of the Tonebender fuzz, most closely comparing to the Coloursound®
Mark ii™. There are many variations of Tonebenders using both germanium and silicon transistors
with different tweaks and values. This project is a great “middle of the road” version. And, it is nothing
less than an absolute Wall of Fuzz. So, have fun!
Notes
•
C5 listed as 10n on some schematics. I prefer 100n in this spot for extra bass.
•
Q1 – Q3: There are many NPN transistors that will work in the Tonebender. Generally, you
want to stick to the lower gains especially for Q1 and Q2. Good ones to use for Q1-Q3 are
2n3904, 2n2222a, BL182, 2n3565, BC108 and 109. You can try higher gain transistors on Q3
such as the 2N5088 or BC459B or C. Pinouts will vary with some of these transistors. The
pinout on the PCB for Q1 – Q3 is the identical to the 2n3904 (C-B-E).
•
T3 is to set the bias on the collector of Q3. Using your DMM, place the black lead to ground
and the red lead on the “TP3” pad. Adjust T3 until you get a reading of about 4.5v. Lower
values (between 3.5-4.5v will result a more compressed and squishy sound
)
.
•
T2 is purely for experimentation. Usually this is a fixed value resistor of 47k. So, start with the
trimpot set halfway up for general bias. You can then experiment with the bias point to find
your optimal fuzz tone using TP2 to monitor changes to Q2’s bias voltage.
•
RPD is an optional pull-down resistor not used on most of the classic Tonebender circuits. It is
not necessary for the circuit to function but can prevent “popping” from bypass switching. You
can socket this resistor to see if you need it or not.
Summary of Contents for TONEBENDER
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