The 21st century is a good time to be a music lover, with high-quality digital audio and streaming audio available on devices ranging from MP3 players to smartphones, laptops, tablets and a range of other portable devices. They sound even better when connected to a full-sized stereo, but that's sometimes a problem if the only available output is a stereo headphone jack. To connect from a headphone jack to your stereo, you can either build your own custom cable or purchase an adapter from a retailer such as Radio Shack.
Preparing a Custom Cable
Purchase a headphone extension cable long enough to reach from the inputs at the back of your stereo to a convenient location for your audio device.
Cut the female end from your extension cable, leaving the jack at the other end. Remove approximately four to five inches of the cable's outer insulation with a stripping tool, hobby knife or box cutter. Be careful not to cut into the braided shield wire underneath.
Peel back the braided shield wire from the inner insulated core. If there's a second foil shield, peel that away and remove it. Carefully cut through the core insulation and remove two to three inches of it. Be very careful not to cut into the wires inside.
Examine the inner wires. There are typically two color-coded wires, usually red and black, and one or two bare copper ground wires. Remove the insulation from the two inner wires using your wire stripper. If there is only one inner grounding wire, untwist it slightly to create a loose bundle of strands, then separate them into two strands. Separate the braided shield wire into two strands as well, and twist each half of the braided shield with half of the ground wire. You should now have two colored wires and two bare copper grounding wires.
Heat your soldering iron and place it on a heatproof surface near your work area with the solder close by. Unscrew the red-coded RCA terminal and slide the outer shell over the red wire and one of the ground wires.
Soldering a Custom Cable
Look at the terminals inside your RCA plug. One will be short and close to the center. The other will be longer and offset to one side. Each will have a small hole in the middle.
Insert the red wire into the hole in the center terminal. Heat the wire and terminal briefly with the tip of your soldering iron, then touch the solder to the area where they meet. It will melt and form a small puddle, joining them firmly. Do the same to attach a ground wire to the second connector.
Slide the RCA plug's outer shell over your newly soldered connectors and screw it back together. Wrap any exposed areas with electrical tape for insulation and added strength.
Repeat the process for the second RCA plug.
Choose a premade cable, usually three feet or six feet in length, with a headphone jack at one end and a pair of RCA connections at the other. These are available off the shelf in multiple levels of quality and provide a simple one-step connection.
Purchase an audio cable of appropriate length with RCA connections at each end, as an alternative. Match it to a Y-adapter or cable that plugs into your headphone jack and provides a pair of female RCA connectors.
Use a premade headphone extension cord to reach from your audio device to the stereo. Connect it to a Y-cable with a male stereo headphone jack at one end and a pair of RCA connections at the other, and plug the RCA connections into your stereo.
- Connect the cable to your stereo with the power turned off to minimize the risk of accidental damage. Turn down the volume on your audio device to a minimum and plug the cable into your headphone jack. Turn on your stereo and select the input where your device is connected. Turn the volume on your stereo to a normal listening level, then slowly turn up the volume on your portable device until it reaches ordinary volume. After it reaches a suitable level, use the volume control on your main stereo for any further adjustments.
- If you want to make a custom cable but aren't confident about soldering, solderless RCA plugs are readily available at retailers such as Radio Shack.
- For a more finished and professional appearance, use a thin piece of heat-shrink tubing over each pair of wires rather than electrical tape. Use a larger piece over the modified end of your cable, leaving just enough space for the connectors to fit your stereo. If you use heat-shrink tubing, place it over the cable before you attach the connectors.
- Be careful to turn the volume down on your portable device before connecting it, and ensure the main stereo either is off or switched to a different input. Excessive volume, or the pop and click of connecting your portable device, can cause permanent damage to your stereo or speakers if you aren't careful.
- Soldering irons can cause serious burns. Keep children and pets out of the room while you're working, and have a heatproof surface or stand for the iron to rest on when it's not in use. Work in a well-ventilated area and avoid inhaling the solder fumes, which are toxic.
- Headphone extension cable
- Wire cutting/stripping tool, hobby knife or box cutter
- Pencil-type soldering iron, either electric or gas powered
- Rosin-core solder
- Two RCA plugs, color-coded in red and black
- Electrical tape (optional)
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