Introduction

The two modules may be used in series with the input to the Fuzz module followed by the Wah otherwise the wah would be ineffective.The wiring arrangement provide for four mode of operation as follows:

1	Wah
2	Fuzz
3	Fuzz-- Wah
Foot	By-Pass

The Wah-Fuzz System

Figure A shows the external wiring for each modules (for identification chose your own wiring colours )
Figure B details the basic power supply wiring. ( See "E" for option )

Figure C Shows the combined wiring of the by-pass switch S4 with the rotary switch mode selection S3. In order to indicate that the by-pass is active a small optional circuit is added , a green LED is indicated ,Q1 can be any high gain PNP small signal transistor , S4 as wired is said to be a true by-pass circuit. Two 100K resistors can be connected to the input and output of S4 to ground to help eliminate the POP from the amplifier when S4 is activated.

Figure D show the wiring details of Rotary switch S3 , position # 1 =Wah , #2 = Fuzz, #3 = Fuzz-Wah. S4 can be activated at anytime to override any of the selected mode.

Figure E Shows an optional circuit to use a wall plug transformer input . Wall plug units have the center pin positive or negative , the circuit uses a protective steering diode bridge , regardless of the polarity input the output of the bridge will always be positive. A 9V regulator is used with a 470uf filter capacitor . The output of the regulator is connected as shown to a SPST switch. A 9V battery can also be used at the same time two diode in series are used to block the higher voltage potential of the regulator to the battery incase the regulator may be lower than 9V otherwise one diode would be sufficient to maintain a half volt lower potential.
In order for the voltage regulator to be effective a wall supply unit rated at 12 volts minimum and 100 mA is required since the total current consumption of the unit including the LEDs should not exceed 20mA and a small regulator in the TO92 package is sufficient. More information can be found here on regulators .

An alternative to the diodes in the battry circuit is to connect the battery to a 2 wires closed contact input jack of the type required by the wall unit output connector. In this case eliminate the diodes and connect the jack battery output directly to the switch.

Input Jack connections

Below is the wiring to illustrate how an input jack can be used for both the signal input and power supply connection instead of using a seperate power on/off switch . As the plug is inserted the negative side of the power supply connection is made with the plug body and the open connector contact while the signal is made with the insulated connector tip of the plug with its own lug .

Electronic by-pass switch

The last drawing shows how you can use two IC's to make and electronic true by-pass switch . A DPDT foot switch cost anywhere from $ 12.00 to $ 17.00 ( canadian $ ) and the price is still going up . You can save up to 2/3 the cost by making your own with simple IC's using a CD4016 or CD4066 and one gate of a CD4049.
The only draw back is that the power supply must on to activate the switch. A simple SPST push button switch can be used , a heavy duty one can be had from most electrical supply stores.

When the power is on and the foot switch is open the CD4016/66 switches c-b and e-f are held closed by the 10K resistance connected to ground allowing for the by-pass position . As soon as the foot switch is closed + 9 volts is applied to pins 12 and 13 of the CD4016/66 and pin 3 of the CD4049 and overcome the grounded gates and allows a-c and d-f to close and insert the circuit between a and d .
A suggested IC layout is shown and a representation of a similar DPDT switch action is shown with the pin connections . Gates resistance is very low and does not affect the signal level , I have tested it after assembly and was very satified with the operation .

I hope you have enjoyed studying this project , if you have any questions please feel free to contact me .