Modifying My Crybaby

My Finished Product

After some unavoidable delays, I just recently finished modifying my Dunlop GCB-95 Crybaby. This pedal was given to me by a good friend who no longer used it and gave it to me to mess around with. It now features true-bypass, a tone control, and switch that turns it into a volume pedal. Some time in the future I'll probably do some more mods, such as adding an LED and a volume control, but for now I'm enjoying it as it is.

True-bypass Conversion

The Crybaby wah is probably the world's most popular pedal of all times. It was created in 1966 and has been used by artists such as Jimi Hendrix and Eric Clapton. Despite its huge popularity, however, there is a drawback to the original (GCB-95) crybaby. Namely, it isn't true-bypass. What that means is that, even when the pedal is off, the signal from your guitar is still passing through a section of the crybaby's circuitry. This causes an undesirable loss of tone from your guitar. Luckily, though, this is easy to remedy.

Step 1 - Get At The Innards
To do any modifications you're going to need to get the circuit board out. Open up the pedal by unscrewing the four rubber feet on the bottom (there were actually only three on mine) and removing the back cover. The inside of your pedal should look something like this:

To get the circuit board out unscrew the bolts from the input and output jacks (a socket wrench comes in handy here). Next take out the screw at the bottom right corner of the circuit board. Then pull the 8-pin connector off (that white plastic thing at the top with all the colored wires). Just pull it straight up and should come right off. Now you should be able to take out the circuit board. If it's a bit tight just push it up towards the switch and you should be able to lift it out. You're now ready begin construction.

 

Step 2 - Remove The Input Buffer

This is the section of the circuit that the signal passes through when the pedal is bypassed. It's possible to convert a crybaby to true-bypass without removing this section, but I chose this method because it's the easiest and most easily reversible way. Simply desolder and remove all the components in the picture below that are circled in red.

Remove These Components

When you're finished it should look like this:

 

Step 3 - Put In The New Wires

This part is simple. Cut two piece of 24AWG stranded wire that will reach from the circuit board to the switch. Solder one of these in the far left hole of the transistor (Q3) that you removed. This is your effect input wire; the wire that the signal from your guitar will enter the effect circuit through. Solder the second wire (which will be your ground) to the bottom hole left by R14.

This is how it should look:

 

Step 4 - Insert And Wire The New Switch

For this part you're going to need either a 2PDT or 3PDT switch. If you're planning on adding LED you'll need a 3PDT switch.

Now desolder the old switch and take it out. Put in the new switch and adjust its height so that you can just barely click it using the pedal.

Next solder the wires to the new switch. Follow this diagram:

Solder the old green wire to the top lug of the first pole.

Solder the old purple wire to the middle lug of the first pole.

Solder the old blue wire to the bottom lug of the first pole.

Solder your new wire coming from R14 to the top lug of the second pole.

Solder your new wire coming from Q3 to the middle lug of the second pole.

Solder a jumper wire between the top lug of the first pole and the bottom lug of the second pole.

 

When you're done it should look something like this:

 Your crybaby is now converted to true-bypass!

 

Wah-To-Volume Pedal Switch

This is a mod that I found quite intriguing. It adds a switch that allows you switch off the "wah" sound and causes a volume pedal-like effect. Note that this doesn't actually turn your pedal into a "true" volume pedal. When you rock back on the pedal it doesn't dwindle your volume away into nothing. It does, however, decrease the volume, and when it's all the way forward it actually increases your volume (which means that you can now use your crybaby as a clean boost pedal too!).

 

To do this, first desolder the 4.7uF capacitor.

Then solder it to a DPDT switch as shown here:

Make sure that the polarity will be correct, and wire the switch to spot where the capacitor was.

Drill a hole in your pedal's enclosure and attach the switch through it.

 

Tone Control Mod

This is another easy modification like the volume pedal switch. Simply desolder the resistor circled in the image below and wire a 100K Linear potentiometer into the holes left by the resistor. Then drill a hole for the pot, give it a knob, and you're ready to go.

 

 

Now put everything back together and have fun! If you have any questions feel free to ask me in the comments section and I'll try to get back to you as soon as possible.