FuzzDog The Wobbler User manual

The Wobbler
EA Tremelo incorporating
runoffgroove improvements
PedalParts.co.uk

Schematic
BOM
R1 1M
R2 1M
R3 4K7
R4 180R
R5 1K2
R6 120K
R7 68K
R8 10K
R9 2M2
R10 15K
R11 1K
Q1 BS170
Q2 J201
Q3 2N5088
C1 47u
C2 100n
C3 470n
C4 22u
C5 470n
C6 1u
C7 1u
C8 1u
TRIM 100K trim
RATE 100KB
DEPTH 220-250KB
VOL 100KA

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 MUST use some kind of heat sink on the legs of the LED and
the transistors when soldering. They aren’t keen on heat. Any more
than a couple of seconds of iron and they’re toast.
ecommended assembly order:
esistors, Caps, Diode, Transistor, Pot, Wires
When assembled adjust the trim until you
have around 4.5V at Q1 drain.
Original circuit was improved by chaps at runoffgroove.com
Input stage by Gez Paton, pulsing LED by Darren Inwood and ob Strand
1 2 3

YRET
T
A
AT
B
NI UO TU
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.
Solder some nice, long lengths of wire to the board connections for
9V, GND, IN, OUT, LED+, LED-. 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. You can either solder the leads to the LED
(you’ll snip the negative one in half later), or connect them to the
LED with crocodile clips. 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.

ire 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
L
E
D
BOARD
OUT
BOARD
9V
BOARD
GND
BOARD
GND
BOARD
GND
BOARD
INPUT
BATTERY
+
IN
OUT
L
E
D
BOARD
LED-
BOARD
LED+
+