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
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)
9v battery clip (http://www.amqrp.org/kits/NCKeyer/elmer/P7190015a.jpg)
Something that can drill, such as a Dremell
Soldering Iron & Solder
Step 2: Prepare the 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
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
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.