DIY ABY Switcher Guitar Pedal

Amp Channel Switcher Pedal

An ABY pedal, also known as an amp switcher pedal or guitar switcher pedal, is a passive control that allows you to switch one input between 2 outputs or two inputs into one output.

If you have two guitar amps and would like to either switch between them during a gig or run them both at the same time, you can use one of these pedals to do just that. Simply run your guitar input into the input of this pedal and run cables from the A and B outputs into the inputs of your guitar amps. That’s right, this is a pedal to switch between amps.

As this pedal isn’t directional you could also use it in reverse to plug two instruments into one amp. For example, you could leave two guitars plugged in and use the A/B button to swap between them during your set.

You can even use a guitar ABY pedal to set up a full stereo rig and run different pedals in each amp. 

It may be a passive pedal that doesn’t do anything to affect your tone, but you can really have a huge amount of fun with this utility and use it to create your own signature sound.

Items Needed

Here’s a list of the items we’ll need to build a single switch guitar amp footswitch:

  • 3 ¼ Inch Mono Jack Input
  • 2 3PDT Footswitch
  • 3 3mm LEDs
  • 2 1K Resistors
  • 1 Hammond 1590B Enclosure
  • Single Core or Stranded Wire

DIY ABY Pedal Wiring Diagram

Below is a wiring diagram of how these components fit together and what the pedal will look like once you’ve finished it.

As you can see, it’s a bit of a birds nest with all of the wires. However, if you follow the below build instructions, you should be able to get this up and running fairly easily.

Quick Tip: If the LEDs either aren’t bright enough or don’t turn on, try a lower value resistor.

Build

To get started with this build, gather together all of your components and lay them out in front of you to make it easier to grab them whilst you’re building this pedal.

Turn on your soldering iron and leave this for a few minutes to warm up to the correct temperature. While you wait for this to heat up, let’s drill the case ready for all of the hardware we’ll need. As we have three jack inputs, one DC input and two footswitches, we need a few holes. The mono jack input will each require a 10mm hole, the footswitch and the DC input will both require a 12mm hole and the LEDs will each require 6mm holes. A good step drill bit will do the job but if you’re using a standard drill bit, you will probably need to run a file or some sandpaper over the holes to smooth out any jagged edges.

Now that your soldering iron is up to temperature, we can prepare all of our hardware components and tin them with a bit of solder to make soldering your wires to them much easier.

As this build consists mainly of wires between the inputs and switches, it makes sense to build this straight into the enclosure. It will save quite a lot of time cable management and make things much easier to follow should you need to do any debugging.

Once you have added a bit of solder to all the connections of your hardware, mount them into the drilled enclosure and tighten all of the nuts. For the jack inputs, try to ensure that the connections are pointing up towards you as this will make it much easier to work with in your enclosure.

For the first set of wiring, let’s get all of your ground wires in as these connect to most of your hardware components. Take one length of wire (preferably black) and attach it to the large lug of the DC power input jack. From the DC power jack, take the wire and attach the other end to the sleeve of the input jack next to it. We then need to add another black wire from that same input jack and connect it to the jack next to that one. Do the same thing for the third and final jack input. This essentially daisy chains all of the inputs together. From the final input, add another black ground wire from the sleeve and take the other end to our first 100K resistor. Add your second 100K resistor to this connection and from that same end, add another wire to terminal 7 of your far right (from your current perspective) footswitch. For the final bit of grounding, add a wire from the same terminal of that footswitch (terminal 7) and run the other end to terminal 3. This completes the ground wiring of this pedal.

Are you still with me?

From the tip of the input jack directly next to the DC input, connect a wire to the first terminal of your furthest right footswitch. Once connected, take another wire from terminal 1 to terminal 9 of the same footswitch. From terminal 9 of that footswitch, take a wire to terminal 9 of your other footswitch (furthest left from your perspective) and connect terminal 9 and 7 of your left footswitch together. Connect the tip of your middle jack input to terminal 6 of your left footswitch and the tip of your left jack to terminal 4 of your left footswitch.

Remember those resistors we wired up to the ground? Take the free end of your first resistor and wire that to terminal 5 of your right hand footswitch and the other resistor to terminal 5 of your left footswitch.

Let’s connect the two footswitches together next. Take a wire from terminal 1 of the left hand footswitch and connect it to terminal 4 of the right hand footswitch. Then, take a wire from terminal 3 of the left footswitch to terminal 6 of the right footswitch.

The last items we have to wire up are your LED’s. LED’s have two connections and you need to wire these up correctly. These connections are called the ‘anode’ and ‘cathode’. If you’re dealing with brand new LED’s, the longer wire will be the anode and the shorter will be the cathode. Another great way to check which end is which is to look at it from the top down. You’ll notice that one side is flat. This is the cathode. Orientate your LED’s so that the cathode is pointing towards the footswitches. Connect the cathode of your left LED to terminal 8 of your left footswitch and connect the cathode of the middle LED to terminal 8 of your right footswitch. Finally connect the cathode of your right LED to terminal 2 of your right footswith.

For the final bit of wiring in this pedal, connect the three anodes of your LEDs together and run a final wire through to the positive terminal of your DC jack input.

Once you have all of this wiring in place, your pedal should be complete.

Plug it in, test it out and add any labels you want to help you see which switch does what. If you’re looking at your pedal the right way up from your pedalboard, the left hand switch will switch between signal paths A or B and the right switch will turn on both A & B.

If something isn’t working, check your connections. The joy of wiring this directly into the enclosure means your wire’s shouldn’t be too long and everything will be relatively neat making it easier to see all of your connections. If there are any loose wires or poor connections, add a bit more solder to make a really good connection. You’d be surprised how easy it can be to miss something like this and by simply reflowing the solder over these joints, you can generally solve your issues. As there are no active components with this build, there is very little else that can go wrong.

As always, happy building but if you hit any snags along the way, please let me know and I’ll help out wherever I can.

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I have been a guitar and effects pedal enthusiast since 2005 and electronics tinkerer since 2017.

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