A/B/Y Switch Box

• A/B/Y Switch Box User’s Guide
• Project History

Passive A/B/Y Instructions

This is a Passive A/B/Y switch box with input grounding (for the input not in use).  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. This project is more complicated than some due to the input grounding.  There are some simpler version schematics in the section below these project files, in case you want to chose a simpler version.

• General Build Instructions
• A/B/Y Switch Box Build Instructions
• A/B/Y Switch Box Bill of Materials Text
• A/B/Y Switch Box Schematic
• A/B/Y Switch Box Parts Layout and Wiring Diagram

Active A/B/Y Instructions

Here are some Diagrams with Active Buffers in the A/B/Y switcher. Once you put active components in it, it can no longer be used “reversible”. It either has A/B/Y inputs or A/B/Y outputs, but not both. So here is a buffered version of each.  These use either the ICBUF PCB or the Dual ICBUF PCB available from this site.

• Switch Box with A/B/Y buffered outputs (Parts Layout and Wiring Diagram)
• Switch Box with A/B/Y inputs and a buffered output (Parts Layout and Wiring Diagram) (Untested!)

Other A/B/Y Schematics

Here are some other examples of ABY switch boxes. We chose the project above as being the best since it has grounding for the unused channel and a separate “A and B” LED indicator, so that when you come out of the “And” mode you will know which channel you will be on.

• A very simple A/B/Y Switch Box Schematic. This is similar to the Morley ABY
• Another simple A/B/Y Switch Box Schematic. Also similar to the Morley ABY but offers a 3rd LED so that you can tell which channel you will be on when you switch out of “A and B” mode.