ABY Guitar Box





Introduction: ABY Guitar Box

This tutorial was also posted in my blog. Check it out for more DIY projects!

This is a A/B/Y box. It acts as a switch. You can plug in a guitar and have it's output go into two amplifiers.
You can choose between the amplifiers or use both at once.
This is a very simple build. As a beginner I had only moderate work.

Step 1: Bill of Materials

Bill of materials:
2x 5mm LEDs
2x 4,7k Ohm Resistors
2x DPDT Switches (http://www.banzaieffects.com/files/images_detailed/d_4217.gif)
3x 1/4 jacks (P-10 jacks - http://www.effectsconnection.com/oscommerce/images/marshallstylemono.jpg)
Plastic container
9v battery clip (http://www.amqrp.org/kits/NCKeyer/elmer/P7190015a.jpg)

Tools needed:
Something that can drill, such as a Dremell
Soldering Iron & Solder

Step 2: Prepare the Compartment

You'll need a plastic or metal compartment.

There should be four holes on top (2 for the LEDs and 2 for the DPDT switches), one hole in front (for the input and two holes on the back for the output.

You could also have an extra hole for a 9v input plug but I didn't use one in this project.

Step 3: Electronics

Now for the fun part... connecting everything.

Follow the schematics available bellow. They are pretty simple.

The drawing was made with BEGINNERS in mind so it doesn't follow any conventions. I believe it is pretty self explanatory.

I tested everything out using a breadboard before soldering. This is a specially useful step for amateurs.

Testing the circuit.
invalid movie: http://vimeo.com/5571157

Step 4: Testing

Now you should have your A/B/Y box.

You plug in your guitar in one end and the amplifiers on the output ends.

By pressing the A/B switch you can choose between any one of the amplifiers as the output.

By pressing the A/B or A+B switch you can choose between using only one of the outputs or using both at the same time (that's the difference between A/B and A/B/Y box).


Testing the finished ABY box.



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Please be positive and constructive.




i find it odd that the author didn't respond to a single question about whether his pedal has issues with noise. Perhaps i can help:

This schematic works, but has a key limitation, which can create noise issues in many cases. If it works for you, great. But, if you have issues with noise, the cause may be because the circuit doesn't ground the bypassed line. The solution to this is simple: use a 3PDT switch, instead, and switch the grounds, as well. If you are willing to do without the LED's, you can use the DPDT switch, still. The schematics to do this are widely available via a quick Internet image search.

The "Y" capabilities of any passive pedal, in which two guitars are routed into one amp, are suspect, in terms of avoiding noise/issues. In a pedalboard configuration, it may work if you have buffered pedals before the "Y", or if you are using active pickups. But, in most cases, the loading will cause negative interaction between the two instruments. The solution to this is to create an isolation circuit, and/or buffer the inputs, but this turns the pedal into an active one, rather than having the passive simplicity. That said, the schematics are some of the easiest to build, but will require some electronics/soldering skills. Another solution might be to use pedals that buffer the input prior to the passive "y". That whole scenario is kinda' hokey, anyway, though. Just get another amp.

For the people asking about the kind of wire, it really isn't a big issue... obviously, if you use a high-quality wire, it will, technically, be better, but, i doubt you'd hear the difference between Canare GS-6 (what i use) or solid-silver-core Teflon-insulated wire, and an off-the-shelf hookup wire. The gauge should probably be between 22 and 18.

Please upload a schematic for that design, as many of us have a hard time visualizing what to connect where

I want to build one of these to run two outputs from my guitar for recording - 1 to a mic'd amp / fx, and one clean line straight into a soundcard, so I am keen to reduce the possibility of noise when running 'Y'.
But I'm also a beginner.. any chance you could point me a wiring diagram for the 3pdt grounded version you're talking about?


alexanderm could u please show me how to make this pedal for two inputs and one output. I want 2 switch between instruments instead of amps... i'm a complete noob at circuitry etc and i cant find anything moderately easy on the internet on this subject :S pls help!

Just plug the instruments into the "outputs" of the box, and the "input" of the box connects to your amp.
I know it sounds odd, but I guarantee it works.

Hi, I get a huming sound on the output that is not on. Is there a way to fix this, or did I do something wrong?
Great instructable BTW. My first DIY project :)

Sorry but the Grounding??

if u remove the LEDs would this work in reverse?

IF you preffer removing leds ( and i know this is a old post ) you can replace DPDT switches with SPDT switches simply leaving out the middle part. It'll function the same way, without the need for supply voltage nor the LEDs. Though I think you may have figured that one out by now :)