FuzzDog Blue Fool User manual

Blue Fool
Octave-down fuzz fun from
this MXR Blue Box clone
PedalParts.co.uk

BOM
R1 2M2
R2 150K
R3 1M
R4 470K
R5 1K
R6 56K
R7 10K
R8 1M
R9 56K
R10 10K
R11 1M
R12 10K
R13 56K
R14 56K
R15 56K
R16 56K
R17 56K
R18 56K
R19 1M
R20 56K
R21 56K
R22 56K
R23 330R
R24 1M
R25 100K
R26 10K
R27 390R
RLED 2K2 (CLR)
C1 10n
C2 1n
C3 330p
C4 10u elec
C5 47n
C6 47n
C7 10n
C8 1u elec
C9 1u elec
C10 100u elec
C11 10u elec
C12 100u elec
C13 100n
C14 220n
D1-3 1N4148
IC1 4558
IC2 CD4013
Q1-3 2N3904
Q4 2N5088
BLEND 50KA
VOL 100KA
SW1 SPD (ONON)
Schematic
Green shaded area is a LPB
boost circuit to bring the
signal level up to above
unity. his isn’t in the
original circuit.
he switch selects between
2-octaves down (original)
and 1-octave down (mod).

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 pots to mount them flush in the
box.
You should use some kind of heat sink on the legs of the diodes
and transistors when soldering. They aren’t keen on heat. Any
more than 3-4 seconds of iron and they’re toast.
I’ve incorporated the Current Limiting Resistor for the LED into
the board for your pleasure.
The switch mounts on the underside of the PCB. You can then
mount the whole board in the enclosure using it. Nice!
I recommend not leaving the switch until last - it can be
awkward to get the soldering iron in once all the components
are in place.
VOLUME - kinda self explanatory. The LPB boost I’ve
incorporated into the circuit will give you plenty of punch
BLEND - between Fuzz and Octave signal.
1 2 3
WITCH
This is optional, but
why wouldn’t you
include it?
If you want to take it
out, connect the switch
pads in one of these
combinations:
2-OCTAVE DOWN
(ORIGINAL)
- connect pads 1and 2
1-OCTAVE DOWN
- connect pads 2and 3
1
2
3

est the board!
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.
older 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 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

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.
This circuit is standard, Negative GND. Your power supply should be Tip
Negative / leeve Positive. That’s the same as your standard pedals
(Boss etc), and you can safely daisy-chain your supply to this pedal.
Now... rattle those speakers!
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