FuzzDog CosmosFuzz User manual

Cosmos Fuzz
Extreme splatter-fest fuzz
from out of this world
Contents of this document are ©2023 Pedal Parts Ltd.
No reproduction permitted without the express written
permission of Pedal Parts Ltd. All rights reserved.

Important notes - DO NOT SKIP!
I you’re using any o our ootswitch daughterboards,
DOWNLOAD THE DAUGHTERBOARD DOCUMENT
•Download and read the appropriate build document for the daughterboard as well as
this one BEFORE you start the build.
•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.
This applies to older PCBs with a pad marked LED next to the IN V G OU pads.
POWER SUPPLY
Unless otherwise stated in this document this circuit is designed to be powered with
9V DC Tip-Negative supply.
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. For kits that use 3mm resistors instead of standard 6mm, these
will usually be either 0.125W or 0.4W.
•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. Stripe indicates cathode.
Diodes/LEDs:
Striped leg (cathode) to square pad. Short leg to square pad for LEDs.
The exception to this is with Russian germanium diodes - stripe = anode.
•ICs:
Square pad indicates pin 1.

Schematic + BOM
R1 1M
R2 10K
R3 10K
R4 39K
R5 1K
R6 560K
R7 100R
R8 10K
R9 6K8
R10 10K
R11 470R
R12 1M
R13 100R
C1 100n
C2 100n
C3 33n*
C4 33n*
C5 100n
C6 100n
C7 100u elec
D1-3 1N5817
D4 Germanium**
IC1 LM386-N1
Q1-3 2N2222***
SUS 100KB
VOL 100KA
*You could just use a 68n in either spot and
leave the other empty.
**We supply Russian D9E. This has the anode
indicated by the stripes rather than the cathode,
so reverse it compared to the PCB silkscreen.
***Should work with any low-medium gain
B Ts, but these reportedly give the best
performance of fuzz frenzy vs unwanted noise.

PCB layout ©2023 Pedal Parts Ltd.
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 diodes and
transistors. They’re very sensitive to heat. You
should use some kind of heat sink (crocodile clip
or reverse action tweezers) on each leg as you
solder them. Keep exposure to heat to a
minimum (under 2 seconds). Same goes for the
IC if you aren’t using a socket.
Snap the small metal tag off the pots so they can
be mounted flush in the box.
You should solder all other board-mounted
components before you solder the pots and
switches. Once they’re in place you’ll have no
access to much of the board. Make sure your
pots all line up nicely.
The best way to do that is to solder
a single pin of each pot in place then melt and
adjust if necessary before soldering in the other
two pins.

Test the board!
Check the relevant daughterboard document or more
in o be ore you undertake this stage.
UNDER NO CIRCUMSTANCES will troubleshooting help
be o ered i 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

Now’s the time
to refer to the
daughterboard
document for
your chosen
bypass method.
Enjoy your pedal!

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
Recommended drill sizes:
Pots 7mm
Jacks 10mm
Footswitch 12mm
DC Socket 12mm
Toggle switches 6mm
32mm
Drilling template
without battery - side DC
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!