Power Supply
The TxFuzz is designed to operate from a 9V DC supply. The transistors in the
TxFuzz can handle higher voltages but there is no advantage to be gained by running
at any voltage greater than 9V DC
External Power Supply
Power can be supplied from a
9V regulated
power pack with a 2.1mm coaxial plug
with
negative
connected to the
centre pin
. The TxFuzz will use only a few Milliamps,
but we suggest that the power pack should be rated at greater than 20mA. The pedal
is protected from reverse power connection by a diode, reverse connected across the
positive and negative contacts of the DC jack. If an incorrectly polarized or AC supply
is connected, this diode will effectively short circuit the supply, protecting the pedal
circuitry from damage.
If an incorrectly polarized power supply remains
connected, the power supply will be damaged.
Battery
The TxFuzz can be powered from from a battery, and a battery compartment is
provided for powering the pedal from a
9V battery.
To access the battery compartment, peel off the non-slip base, which is attached with
genuine Velcro, commercial quality, hook and loop tape. Remove the four screws that
hold the bottom of the box in place.
The battery snap is held to the inside of the box with Velcro. Separate the Velcro and
attach the snap to the battery. The battery will fit between the switch and the end of
the box. The pedal serial number is also located in this area.
Replace the bottom of the box and the non-slip base.
Note:
The bottom of the box
has foam rubber on the inside, but the rubber does not cover the area where the
battery sits. If the bottom is the wrong way round, it won’t fit over the battery.
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TxFuzz Description
The TxFuzz is based on the same Voltage Feedback Biasing topology that gave us
the Fuzz Face, with one major difference. The TxFuzz as an output transformer.
The story behind the TxFuzz is that, a few years ago, a friend persuaded me to build a
silicon version of the Fuzz Face, just for fun.
I was not very impressed with the Silicon Fuzz Face in its basic form, and even adding
the various modifications from around the Internet didn’t help much. At best, there
was very much a Solid State harshness to the tone.
I had already designed the Blue Classic with transformer coupling to soften the
harshness of overdriven transistors, so I decided to try a transformer in the Fuzz Face.
The impedance of the transformer from the Blue Classic did not really suit the Fuzz
circuit, but I soon found a transformer that sounds great and, as a bonus, gives a lot
more output than the original circuit.
Using an output transformer enabled me to separately optimize DC bias conditions
and AC signal conditions. This allows the TxFuzz to cover a lot of ground, from Clean
Boost with some “flavour” through Overdrive and Distortion to High Gain Sustaining
Fuzz.
Using the TxFuzz
Stomp Switch
The switch is 3PDT, True Bypass and has gold contacts for reliability.
Note:
The switch can assume a “half-operated” state if the plunger is bumped during
travel and set-up. This is a characteristic of the switch mechanism and
not
a fault.
Always fully operate the stomp switch once before using the pedal.
Volume Control
The Volume control works like most volume controls. When fully counter-clockwise,
there is no output from the pedal. When fully clockwise, pedal output is maximum.
Fuzz Control
The Fuzz control varies the gain of the pedal. When fully counter-clockwise, pedal
output is clean. As you rotate the control clockwise, gain will increase.
Guitar Volume
You will find the TxFuzz very responsive to guitar volume. Even with the Fuzz control
set fully clockwise, the TxFuzz will clean up significantly when you back off the guitar
volume. Similarly, the TxFuzz is much more sensitive to playing dynamics than a
regular Fuzz Face
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