Elementary Bypass

by Aron Nelson 7/03

A common question is how to convert your pedal to true bypass.

This is not a complicated thing to do.

What you are trying to do is make the bypassed state a straight wire using a DPDT switch.

Here's how an old effect (non true-bypass) typically works.

The signal is split right at the input to the effect(FX) and then the output switch will select the output of the effect or the signal that is "tapped" from the input of the effect. The problem is that sometimes the FX can "load down" the input of the guitar even when bypassed and dull the signal of the guitar.

What you ideally want to do is to use a DPDT switch and when bypassed, have a straight wire carrying the signal in bypassed mode.

Here's how a typical DPDT will switch between 2 states.

First StateThe "top" and middle contacts connect in this first state.

2nd StateThe "bottom" and middle contacts connect in this 2nd state.

The switch will toggle between the two states.

What you want to do is to connect your FX board to the switch like this:

See how the switch will send the signal to either the FX board or to the wire connected to the "bottom" lugs?

In the first state (pictured above), the input will go to the FX board. The output of the FX board will be connected to the out jack.
In the 2nd state (pictured above), the input will connect to the wire connected to the bottom lug and connect right to the output jack.

To recap:

Identify your input and output wires on your effect board. Also identify the input and output wires from the input and output jack.

Replace the existing switch with a DPDT.

Connect the wires as shown above.

For more information, consult the excellent article: The ins and outs of Bypassing Effects on GEOFEX.COM.