FuzzDog BSIAB2 User manual

BSIAB2
Brown ound In A Box -
high gain distortion fun
PedalParts.co.uk

chematic
BOM
R1 1M
R2 390R
R3 680R
R4 1M
R5 1M
R6 470K
R7 1M
R8 1M
R9 120R
R10 82K
R11 5K6
R12 82K
R13 47K
R14 10K
R15 10K
R16 2K2 (CLR)
C1 250p
C2 220n
C3 1u
C4 68n
C5 22n
C6 470p
C7 150p
C8 100n
C9 22n
C10 100n
C11 22n
C12 2n2
C13 1u elec
C14 2n2
C15 100u elec
D1 1N4148
Q1 2N5457
Q2 2N5457
Q3 J201
Q4 J201
Q5 2N5457
DRIVE 500KA
TONE 100KB
VOL 100KA
TRIM 100K*
*Original spec is 100K - I supply 47K. Much easier to tweak the sweet spot.

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 pots to mount them flush in the box.
You should use some kind of heat sink on the legs of the diode 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.
Once its all built and hooked up to test (see next page), adjust the
trimmer. You’re aiming to have the voltage at the Drain of Q5 at
around 50% of the supply voltage. Note - the diode will drop the
voltage going to the circuit by around 1V.
So.. get your multimeter and hook it up to a convenient GND point.
Measure the voltage at the negative side of D1 (A). Now, measure
the voltage at the Drain of Q5 (D) and adjust the trimmer until you
hit around 50% of (A)’s voltage. That’s your starting point. Now fine
tune by ear until its perfect for you.
1 2 3
D
A

Test 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.
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. lug 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 / Sleeve ositive. That’s the same as your standard pedals
(Boss etc), and you can safely daisy-chain your supply to this pedal.
Now... CCCRAAAAAANNNNGGGGGGG!
edal arts.co.uk
L
E
D
BOARD
OUT
BOARD
9V
BOARD
GND
BOARD
GND
BOARD
GND
BOARD
INPUT
BATTERY
+
IN
OUT
L
E
D
BOARD
GND
BOARD
LED+
+