FuzzDog Rodent User manual

Rodent
Gnawingly-good distortion
with switchable clipping
PedalParts.co.uk

Schematic
B M
R1 1M
R2 1K
R3 560R
R4 47R
R5 1K
R6 1K5
R7 1M
R8 10K
R9 47R
R10 10K
R11 10K
R12 1M
C1 22n
C2 1n
C3 100p
C4 33p
C5 4u7
C6 2u2
C7 4u7
C8 3n3
C9 22n
C10 1u
C11 100u
C12 47u
C13 47n
Q1 2N5458
IC LM308N
or P07
D1 1N4001
FILT 100KA
DIST 100KA
V L 100KA
D2,3 PAIR*
D4,5 PAIR*
*CLIPPING DI DES
There are lots of variations for these, but stock sets are:
Standard 1N4148
Turbo Red 3mm LEDs
Dirt Germanium (1N34A)
Switch selects between each pair, or you can hardwire a single pair by connecting
SW2 to either SW1 (D2,3) or SW3 (D4,5) with a jumper. Not a woolly one mind you.

Wiring shown overleaf will disconnect the battery when you
remove the jack plug from the input, and also when a DC
plug is inserted.
nap the little metal tag off the pot to mount it flush in
the box.
You MU T use some kind of heat sink on the legs of the
LEDs, diode and the transistors when soldering. Also be
very careful if you’re soldering the IC directly to the board
rather than using the socket. They aren’t keen on heat. Any
more than a couple of seconds of iron and they’re toast.
If you want to get really jiggy with it you can take a look at the Ruetz mods -
http://www.diyguitaramp.com/rat.html
Easy enough to implement and easily switchable too.
1 2 3
Diode selection
switch numbering
(viewed from bottom) >
Requires a PDT switch (ON-ON).
1
2
3

Test the board!
Once you’ve finished the circuit it makes sense to test it 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.
older some nice, long lengths of wire to the board connections
for 9V, GND, IN, 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 it works, crack 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.

Wire it up
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.
PedalParts.co.uk