A/B Switch Box

This is a simple  A/B switch box.  There are some examples of how to use this box below.  The circuit is passive except for the LED indicators to indicate which “channel” is active. The two channels are interchangeable as input or output channels as illustrated in the examples below.

There are a lot of limitations to the use of passive A/B switch boxes, but we’ve also found them to be useful in many cases as well.  You may experience problems with hum and noise especially if you use the A/B outputs into to separate amplifiers.


Here are some diagram examples of some of the most common uses of a passive A/B switch.

The first example is a set up to enable silent tuning in a live gig environment.  Your guitar is input with one output channel  to your amp, the other to the input of your electronic tuner.  This is a very popular use for passive A/B Switches.

Example 2 is to split your signal into two amps.  With this box, you would be choosing the signal to go to either amp A or amp B.

Example 3 is used if you have two guitars into one rig, live or in the studio. Here the 2 channels are input channels, one for each guitar, with the output going to your pedal board or amp.

Example 4 is a very useful function for studio rig set up or testing different effects pedals. Here the A/B switch is used as a “Kill” switch.  Locate the A/B switch box at the end of your effects chain and use it to switch off the input while you unplug/plugin different pedals to try out in your rig.


Buy an A/B Switch Box Complete Kit. Includes all the parts and materials you need to build one, all for about the price you would pay for the parts.