FuzzDog Fuzz Face User manual

Fuzz Face
Classic loveliness for all!
PedalParts.co.uk

Schematic
BOM
Classic version - Hendrix/Mayer
changes shown in blue)
R1 100K
R2 33K
R3 470R / 1K
R4 preset 47K
C1 2.2u
C2 22u
C3 0.01u
Q1,2 So Many Options!!!
FU 1KB / 2KB
VOL 470-500KA
Oh my. If ever there was an essential
addition to a rig then the Fuzz Face
surely is it. A bit of fiddling will get
you anywhere from creamy
smoothness to ear-splitting youch
with the right/wrong selection of
those all-important transistors sitting
at Q1 and Q2. Biasing is key!
The schematic above shows the original PNP - Positive-Ground layout,
which is also how the PCB is designed. What does that mean? Well,
basically it means it won’t play nicely with ‘normal’ pedals if you try to
daisy chain them on the same power supply. Don’t do it. The world will
implode and we’ll all look at you.
It’s perfectly simple to make a NPN - Negative-Ground version. Use NPN
transistors, flip the orientation/polarity of C1 and C2, then follow the
appropriate wiring diagram later in these instructions. The -9V connection
become +9v.
Probably sounds more complicated than it actually is.

Latest version of the PCB lets you mount the pots straight onto it, saving on wiring
and eliminating the worry of how to fix the board inside the box. You can wire them
off-board if you like, just connect wires to VOLU E and FUZZ pads 1-3 instead of
sticking the pot into it.
The wires for OUT, IN, 9V and GND can be connected on either side of the board,
depending how you want to route the wiring. The pads are connected to both sides
of the PCB.
Wiring shown overleaf will disconnect the battery when you remove the jack plug
from the input, and also when a DC plug is inserted.
Snap the little metal tag off the pot to mount it flush in the box.
You UST use some kind of heat sink on the legs of the transistors
when soldering. They aren’t keen on heat. Any more than 3-4
seconds of iron and they’re toast.
Recommended assembly order:
Resistors, Caps, Transistors, Wires, Pots
As stated on the previous page, this is labelled for PNP builds.
Reverse C1 and C2 and treat -9V as +9v for NPN builds.
R4 is actually a preset variable resistor, marked ‘bias’ on the
board. ore about the importance of that overleaf.
HANG ON!!!!??! The board has two extra caps - C4 and C5? Yes. There’s
space there for optional smoothing caps for both transistors. If you find there’s too
much top-end fizz going on just put a cap in one, t’other or even both those spots.
The bigger the cap, the more frequency it’ll tame. Anything from 10pf to 150pf will
work. Have a fiddle and see what works for you. Socket them and switch around
until you have aural nirvana. Unlike you’ll need them with germaniums though.
C3 cuts a lot of the bass from the signal before the output. If you want it slightly
beefier just increase this cap. Anything up to 100n (.1u) is cool beans.
If you find you’re getting an audible ‘pop’ when engaging the circuit, just stick a 1
resistor between the “BOARD INPUT” and “BOARD GROUND” lugs on the switch.
1 2 3
C
B
E
E
B
C

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.
Before you start, take a small screwdriver and position the biasing preset in the middle of its turn.
You’ll adjust this shortly.
Refer to the appropriate diagram depending on the polarity of your build. 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!
It may sound cack, as you haven’t set the biasing of the transistors yet. For this you’ll need either a
digital multimeter (ideal) or your ears (hey, its your pedal and you know what sounds good).
Place the Negative D test probe on any GND point, place the other probe on the collector of Q2.
You can actually place it on the left-hand pad of C4 as this connects directly to the collector, and
you haven’t soldered anything into C4 yet, probably. Adjust the bias preset (R4) until you get a
reading of around 4.5V, give or take. Or, if you’re using your ears, until you get the right balance
between volume and fizz. It should be pretty obvious when it hits the sweet spot.
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.
YRET
T
A
AT
B
NI UO TU
YRET
T
A
AT
B
NI UO TU
PNP
NPN
Test the
board!

PNP cans? Follow this.
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 non-standard, Positive GND. Your power supply should be
Tip Negative / Sleeve Positive, but strange things happen when the juice
hits the circuit. DO NOT daisy-chain your supply to this pedal with
normal, negative ground pedals. Bad things WILL happen.
Now... GO GET FUZZY!
PNP CANS?
Ooh, many, but how about:
AC128
2N404

NPN cans? Follow this.
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.
Now... GO GET FUZZY!
PedalParts.co.uk
NPN CANS?
Ooh, many, but how about:
AC176
BC108 (silicon)