I used to use JHymn to convert my iTunes songs over to MP3's to open them to Linux. I own an iPod, so my only concern was the ability to play them under Linux. This was killed when iTunes 6.0 came out, however. So I'm now sharing my music collection on the Linux box with my laptop in iTunes so I can listen to everything I have. But it's a pain to switch the audio cable between the two computers depending on which one I'm using. I didn't want to waste my money on one of those cheap A/V switchers from RadioShack or the like, so I took the next best route: build my own.
I'm not attempting to build a high-quality sound mixer, just a simple switch between two audio sources. I had several 3.5mm stereo jacks, 2-way parallel switches, and a project lying around, which cost me maybe $10 from online retailers.
In addition to the parts, I also needed a drill, screwdriver, pliers, scissors, soldering iron/gun, and an exact-o knife.
The first step was to mark off holes to drill. I had two audio inputs, 1 output, and 1 switch. I also added a fifth hole just in case I ever felt the need to be able to split the output (headphones or sound system).
That being done, the jacks themselves are 1/8", and the casings make it slightly larger, so I figured a 3/8" bit would do the trick. Just clamp your project box and make sure you're wearing safety glasses, melting plastic can damage your yes and possibly burn your skin. The job looks about right to me.
Make sure there's plenty of room around the holes to mount inside. Sand or file away any melted plastic so everything is nice and flat and the jacks mount flush.
Next step is to begin soldering. Each jack has three leads: left signal, right signal, and ground. We're going to start with the left signal (it was farthest from the top. From the inputs, I ran wire to the switch in the center on opposing sides, then ran the center lead on the switch to the left channel lead on the output jack.
Repeat this for the right leads, then run the both ground signals from the input to the output. You'll solder both wires to the same lead. You should have something like this when you're done.
If I'd done it right, I should have been able to run audio from my laptop and desktop into the switcher and connected the output to my speakers. After checking all the connections, it worked! I was able to use the switch to switch back and forth with no issues.
It may be done for now, but I'm running a 5.1 System and only running 2-channel audio into it. Once I get a new receiver, I may use the switcher for SPDIF Digital Audio. Also to note, I think the sound might be ever so slightly lower in volume than before, so I could add a simple stereo amplifier to it, but adjusting the volume on the PCs or speaker system is sufficient for now. Plus there's already 2+ volumes to adjust on each PC and the volume on the speakers. Why add another volume control?
I also ran into some mounting issues with the project box. It was so easy to sand inside the box, even with a dremel. I could have mounted the parts on different sides, but I probably could have a taken a slightly more popular route and mounted it inside a mint tin. Maybe for a future upgrade!
I hope this was useful to someone. Enjoy!
