HERE ARE PLENTY of audio-
video (A-V) source selectors available off-the-shelf but here’s a low-cost unit that you can build yourself. It’s easy to assemble and you will no longer have to muck about swapping A-V cables each time you want to change the video source.

The unit provides 4-channel switching for both S-video and composite video sources but why not provide for component video and RGB as well? And why didn’t we allow for switching 5.1-channel or even 7.1-channel audio, instead of settling for just stereo/Pro Logic or digital bitstream audio?

There’s a simple one-word answer to these questions: cost. If we had provided those extra options, the circuit complexity would have grown significantly and the parts to build the selector would probably have cost you $150 or more, instead of the $50 or so that this unit will cost.

In short, there had to be a compromise between providing all of the features anyone might want and making it attractive to as many people as possible.

During the design phase, we did give consideration to providing for component video/RGB switching. However, this would have required at least four extra relays, five extra video connectors and a larger and more expensive box to house the circuitry. So considering that most of the wide-screen TVs and plasma panel screens which accept component video also have at least two input ports, we decided to draw the line at S-video and composite video switching.