FuzzDog One-Knob Fuzz(es) User manual

One-Knob Fuzz(es)
A lot of fuzz, a little build
Contents of this document are ©2019 Pedal Parts Ltd.
No reproduction permitted without the express written
permission of Pedal Parts Ltd. All rights reserved.

Important notes
If you’re using any of our footswitch daughterboards,
DOWNLOAD THE DAUGHTE BOA D DOCUMENT
•Download and read the appropriate build document for the daughterboard
as well as this one BEFORE you start.
•DO NOT solder the supplied Current Limiting Resistor (CLR) to the main
circuit board even if there is a place for it. This should be soldered to the
footswitch daughterboard.
POWE SUPPLY
Unless otherwise stated in this document this circuit is designed to be
powered with 9V DC.
COMPONENT SPECS
Unless otherwise stated in this document:
•Resistors should be 0.25W. You can use those with higher ratings but
check the physical size of them.
•Electrolytics caps should be at least 25V for 9V circuits, 35V for 18V
circuits. Again, check physical size if using higher ratings.
LAYOUT CONVENTIONS
Unless otherwise stated in this document, the following are used:
•Electrolytic capacitors:
Long leg (anode) to square pad.
•Diodes/LEDs:
Striped leg (cathode) to square pad. Short leg to square pad for LEDs.
•ICs:
Square pad indicates pin 1.

Schematic
+ BOM
COLO SOUND
R1 150
R2 10
R3 820R
R4 2 2
R5 1
R6 1M
C1 100n
C2 220n
C3 220p
C4 10u
C5 empty
Q1 BC109
Q2 BC108
VOL 500 A
66BALLS
R1 47
R2 10
R3 1
R4 8 2
R5 1
R6 1M
C1 220n
C2 6n8
C3 220p
C4 10u
C5 empty
Q1 BC109
Q2 BC108
VOL 500 A
FUZZBLOOD
R1 100
R2 47
R3 100R
R4 5 6
R5 1
R6 1M5
C1 100n
C2 100n
C3 220p
C4 10u
C5 empty
Q1 2N2222A
Q2 2N2222A
VOL 500 A
CE EMONY
R1 150
R2 10
R3 820R
R4 2k
R5 1
R6 1M
C1 680n
C2 220n
C3 150p
C4 10u
C5 empty
Q1 2N2222A
Q2 2N2222A
VOL 500 A
*C5 has been added to the board so you can make
even more variations, such as the THUG, or just to
tame some top end fizz on any of the circuits
below. Add your choice of small cap - (47p - 470p).

THUG
R1 120
R2 18
R3 820R
R4 4 7
R5 1
R6 1M
C1 10n
C2 22n
C3 470p
C4 10u
C5 47p
Q1 2N3904
Q2 BC182L*
VOL 500 B
THUG DA K
R1 120
R2 18
R3 820R
R4 4 7
R5 1
R6 1M
C1 47n
C2 100n
C3 470p
C4 10u
C5 47p
Q1 2N3904
Q2 BC182L*
VOL 500 B
E C B BC182L
E B C 2N3904
The BC182L used in the two THUG variants has a
different pinout to most of the other transistors
used in the O F circuits. We’ve added an extra
Emitter pad for Q2 so you can easily mount this
transistor without any awkward leg twisting.
E C B
X
E
C
B

The power and signal pads on the PCB
conform to the FuzzDog Direct Connection
format, so can be paired with the
appropriate daughterboard for quick and
easy offboard wiring. Check the separate
daughterboard document for details.
Be very careful when soldering the
transistors. They’re very sensitive to heat.
eep exposure to heat to a minimum
(under 2 seconds) and leave a few seconds
between soldering each leg.
Snap the small metal tag off the pot so it
can be mounted flush in the box.
You should solder all other board-
mounted components before you solder
the pot. Once it’s in place you’ll have no
access to much of the board.
PCB layout ©2019 Pedal Parts Ltd.

Test the board!
Check the relevant daughterboard document for more
info before you undertake this stage.
UNDE NO CI CUMSTANCES will troubleshooting help
be offered if you have skipped this stage. No exceptions.
Once you’ve finished the circuit it makes sense to test is before starting on the switch and LED
wiring. It’ll cut down troubleshooting time in the long run. If the circuit works at this stage, but it
doesn’t once you wire up the switch - guess what? You’ve probably made a mistake with the switch.
Solder some nice, long lengths of wire to the board connections for 9V, GND, IN and OUT. Connect
IN and OUT to the jacks as shown. Connect all the GNDs together (twist them up and add a small
amount of solder to tack it). Connect the battery + lead to the 9V wire, same method. Plug in. Go!
If you’re using a ribbon cable you can tack the wires to the ends of that. It’s a lot easier to take them
off there than it is do desolder wires from the PCB pads.
If it works, carry on and do your switch wiring. If not... aw man. At least you know the problem is
with the circuit. Find out why, get it working, THEN worry about the switch etc.
Your completed circuit board
including pots

Wiring shown above will disconnect the battery when you remove the jack plug
from the input, and also when a DC plug is inserted.
The Board GND connections don’t all have to directly attach to the board. You
can run a couple of wires from the DC connector, one to the board, another to
the IN jack, then daisy chain that over to the OUT jack.
It doesn’t matter how they all connect, as long as they do.
This circuit is standard, Negative GND. Your power supply should be Tip
Negative / Sleeve Positive. That’s the same as your standard pedals (Boss etc),
and you can safely daisy-chain your supply to this pedal.
L
E
D
BOARD
OUT
BOARD
9V
BOARD
GND
BOARD
GND
BOARD
GND
BOARD
INPUT
BATTERY
+
IN
OUT
L
E
D
BOARD
GND
BOARD
9V
+
Wire it up (if using a daughterboard please refer to the relevant document)

This template is a rough guide only. You should ensure correct marking of your
enclosure before drilling. You use this template at your own risk.
Pedal Parts Ltd can accept no responsibility for incorrect drilling of enclosures.
FuzzDog.co.uk
Drilling template
Hammond 1590B
60 x 111 x 31mm
It’s a good idea to drill the pot and
toggle switch holes 1mm bigger i
you’re board-mounting them.
Wiggle room = good!
Recommended drill sizes:
Pots 7mm
Jacks 10mm
Footswitch 12mm
DC Socket 12mm
Toggle switches 6mm