True Bypass for Dunlop GCB95 Rev.E, Rev.F and Rev.G

Revision E was the first Crybaby to have PCB-mounted jack sockets. Revisions F and G have a buffer at the input, which is supposed to obviate the need for true bypass. The input buffer has a much higher input impedance than the original wah circuit and preserves more of the highs in your guitar signal.

Rev.E Crybaby

You will need to sever the track connecting the input jack to the 68K resistor (blue-grey-orange), or desolder the lead at the input and pull it free of the board. The new wire from the switch is then soldered to the lead of the resistor.

Rev.F and Rev.G Crybaby

If you want to convert to true bypass and keep the input buffer, you'll have to either cut through the track connecting the jack socket and the input capacitor, or desolder the lead at the input and pull it out of the board. The new wire from the switch should be soldered to the lead of the input capacitor,indicated by the yellow arrow. It looks like a resistor on this early Rev. F board, but it is a capacitor.

Alternatively, you can just ditch the buffer circuit (the components ringed in green) and run the new wire to one of the two holes circled in green. Obviously, there's no need to cut the track if you remove the buffer circuit. It's not necessary to remove all the buffer components; but at least the transistor and the 10K resistor should be removed.

Instructions - Retaining Input Buffer

This diagram shows how it should be wired.

1. Remove the board and sever the track between the input jack and the capacitor, as shown on the photo above.

2. Reinstall the board

3. Desolder the wiring from the existing switch.

4. Remove the switch and replace with the new one.

5. Solder a new length of wire to the upper right lug on the switch.

6. Solder the free ends of the green wire and the new wire to the lower left lug on the switch.

7. Solder the purple wire to the lower middle lug on the switch.

8. Solder the short blue wire to the lower right lug on the switch. Some models have the two blue wires connected at the pot, some at the switch.

9. Solder a new wire between the upper middle lug on the switch and the input capacitor on the board.

10. Solder a new wire between the upper left lug on the switch and the grounded lug of the pot.

Instructions - Eliminating Input Buffer

This diagram shows how it should be wired.

1. Remove the board and desolder the buffer components, as shown on the photo above.

2. Solder a new wire into the hole where the emitter of the transistor was.

3. Reinstall the board and solder the free end of the new wire to the upper middle lug on the switch.

4. Desolder the wiring from the existing switch.

5. Remove the switch and replace with the new one.

6. Solder a new length of wire to the upper right lug on the switch.

7. Solder the free ends of the green wire and the new wire to the lower left lug on the switch.

8. Solder the purple wire to the lower middle lug on the switch.

9. Solder the short blue wire to the lower right lug on the switch. Some models have the two blue wires connected at the pot, some at the switch.

10. Solder a new wire between the upper left lug on the switch and the grounded lug of the pot.