Description:
The Mojotone Wah Pedal kit is designed to replace the electronics in any Dunlop Crybaby or Vox V847 wah
pedal for more control and better tone and function. As you may notice, only premium parts are used in the
kit. New features have been added to the classic circuits: true bypass, a 150kL potentiometer to broaden the
sweep range, an optional output buffer, and on board tone controls to tweak the overall sound to your
personal taste.
What is Included in the Kit:
Wiring Diagram
Instructions for Installation
1 Mojo Wah PCB
1 9V Battery Connector Clip
2Ft 22Ga Blue Stranded Pre-tinned Wire
2Ft 22Ga Green Stranded Pre-Tinned Wire
2Ft 22Ga White Stranded Pre-tinned Wire
1 Mojo 2 Conductor 1/4” Jack
1 Mojo 3 Conductor 1/4” Jack
1 Mojo Red 150kL Wah Pot
1 Mojo DPDT Footswitch
(D1) 1 1N4001 Diode (Crybaby Only)
(C4) 1 0.001µF Capacitor (Crybaby Only)
(C9) 1 0.0047µF Capacitor
(C1, C8) 2 0.01µF Capacitors
(C5, C7) 2 0.047µF Capacitors
(C2, C3) 2 0.1µF Capacitors
(C6) 1 1µF Capacitor
(C10) 1 4.7µF Electrolytic Capacitor
(R8) 1 220 Ohm Resistor
(R7) 1 470 Ohm Resistor
(R9, R10, R12) 3 1k Ohm Resistors (R10 Crybaby Only)
(R5) 1 1.5k Ohm Resistor
(R6) 1 4.7k Ohm Resistors
(R13) 1 10k Ohm Resistor
(R2) 1 22k Ohm Resistor
(R16) 1 33k Ohm Resistor
(R15)1 56k Ohm Resistor
(R1, R17) 2 68k Ohm Resistors
(R14) 1 82k Ohm Resistor (Crybaby Only)
(R14) 1 100k Ohm Resistor
(R3, R4) 2 470k Ohm Resistors
(R11) 1 1M Ohm Resistor
2 2N3904 NPN Transistors
1 2SK363 N Fet Transistor
5 SPST Slide Switches
1 DC Power Jack
1 Inductor
Installation:
Begin the installation by determining which circuit to build, the Crybaby or V847. Populate the PCB with the
proper components. Match the labels on the PCB to those in parentheses next to the part in the list above.
Once the components are in place, solder them to the PCB. In order to complete the V847 circuit in which
R10 is not used, solder a metal jumper wire across the pads of R10.
Note: There is no need to consider direction when installing the SPST switches to the PCB.
Note: Install the 2SK363 in the TO-92 footprint farthest to the right on the PCB.
Remove the four rubber feet and their screws from the wah chassis. Remove the bottom panel to reveal the
electronics. Remove the electronics from the chassis. Do not remove the plastic tensioner next to the wah
potentiometer.
Determine whether or not to use the provided DC power jack. Some wah models are not equipped with DC
power jacks, so the chassis will not have a hole for access. Others include a stand alone jack separate from
the PCB.
If the DC power jack is not used, solder the red lead of the 9V battery connector clip to the pad designated
for the positive side of the DC Power Jack. This pad is directly above the pad for the negative black lead of
the 9V battery connector clip.
If this kit is used to upgrade a wah model that is equipped with a stand alone DC power jack, connect and
solder leads from it to the corresponding pads for the DC power jack on the PCB.
If this kit is used to upgrade a wah model that is not equipped with a DC power jack, and use of the one
supplied with the kit is desired, a 1/2” diameter hole will need to made into the chassis. A step bit is
recommended for this.
Install the Mojo DPDT Footswitch, the Mojo 3 Conductor 1/4” jack on the input side, the Mojo 2 Conductor
1/4” jack on the output side, the Mojo Red 150kL Wah Potentiometer, and the Mojo Wah PCB into the
chassis.
Determine whether or not to use the optional output buffer found on the board; the pads for which are
unmarked.
Follow the wiring diagrams on page 3 to complete the wiring of the new circuit. The color coding of the
wires is arbitrary. The second wiring diagram depicts the use of the optional output buffer.
Note: Be sure to adjust the wah potentiometer for the desired range. The rack arm will not turn the pot to its
extremes. We suggest setting it to turn closer toward the higher frequencies.
Using the Tone Controls on the PCB:
The pedal will operate as the original Crybaby/V847 circuit when all switches are in the position closest to
the heel end of the pedal except for the Sweep Range Middle switch which should be slid forward. Try
different combinations of switch positions including multiple switches in the forward position at the same
time.
Equalization:
Sliding the Midrange switch forward will boost the midrange frequency during wah pedal operation.
Sliding the Gain/Bass switch forward will boost the bass frequency and add slight gain to the signal during
wah pedal operation.
Voice:
Sliding the Voice switch forward will change the overall sound of the pedal from a “wah” sound to a “woh”
sound during wah pedal operation.
Sweep Range:
Sliding the Sweep Range Middle switch back will move the sweep range toward the higher frequencies
during wah pedal operation.
Sliding the Sweep Range Low switch forward will move the sweep range toward the lower frequencies
during pedal operation.
Sliding both Sweep Range switches forward will create a wah range good for use with a bass guitar.
Once the desired sound has been obtained, replace the bottom panel and the four rubber feet with their
screws to complete the installation of the Mojo wah pedal kit.