One of the most versatile connectors for audio and video use is the familiar RCA plug. It was originally developed by the RCA Victor company as a way to connect its record players and radios, and it is still used today for connecting audio components. Some manufacturers and hobbyists also use RCA plugs to connect speakers because of its convenience and ready availability. RCA connectors can be used with conventional, two-strand speaker wire or shielded coaxial cables.
Measure lengths of two-strand speaker wire that will reach from your amplifier to the speakers. Separate the two strands at one end of the first wire, pulling them apart for approximately 2 to 2 1/2 inches. Repeat at the other end, and then do the same with the second wire.
Strip the insulation from the last 1/4- to 3/8-inch of wire and twist the strands together tightly. Unscrew the shield from the first RCA connector and slide it down over the wire. If you have both an outer shield and an inner insulator, place them on the wire in that order.
Examine the terminals inside the RCA connector. One will be in the center, and it's usually a brass, copper or aluminum terminal. That is the positive terminal. The second is a longer terminal, usually with a hole for the wire and a pair of small lugs that can be crimped down to hold the wire in place. That's the negative terminal.
Identify the two sides of your speaker wire. One of the two strands is always identified in some way. The wire itself might be a different color, it might have a stripe or lettering on it, or the insulation might be patterned with a series of ridges. The marked side corresponds to the negative terminal on your RCA connector.
Solder the unmarked side of your wire to the center terminal of the RCA connector, using rosin-core solder and a pencil-style soldering iron with a fine tip. Attach the marked side of your wire to the negative terminal by looping its end through the hole, then crimping the lugs to hold it in place. Finish the connection by soldering the wire to the terminal.
Slide the outer shell up over the wire and screw it back into place over the connector. If your connector has an inner insulating sleeve, slide that back into place first.
Measure and cut a length of coaxial cable for each of your speakers. Use a small, sharp knife or a coaxial cable stripper and remove approximately 1/2- to 5/8-inch of the external insulation, revealing the braided insulating cable. Fold the braid back over the remaining insulation, baring the white inner insulation surrounding the core wire.
Trim away 1/4-inch to 3/8-inch of the inner insulation with a sharp knife, taking care not to nick the cable's core wire. Strip and trim the remaining cable ends the same way.
Unscrew your first RCA connector and slide the outer shell down over the end of the wire. If an inner insulating sleeve is present, slide that over the cable as well.
Examine the terminals in your connector. One is relatively short and located in the center of the connector; that's the positive terminal. The other is longer and at the side of the connector. That's your negative terminal.
Solder the core wire of your coaxial cable to the positive terminal in the center of the connector. Roll the braided wire forward and twist it together into a tight strand. Solder the strand of braided shielding to the negative terminal.
Slide the outer shell up over your cable and thread it back onto the connector. Repeat for the remaining three speaker cable ends.
- If you're likely to rearrange the room, allow an extra two to three feet of speaker wire to give yourself some flexibility.
- For general-purpose use, 16-gauge speaker wire is adequate. For longer runs or high-power amplifiers and speakers, 12-gauge or 10-gauge wire offers better signal transfer. For best results, match your connectors to the grade of cable you've chosen. Inexpensive lightweight connectors are acceptable on conventional speaker wire, while heavy-duty, gold-plated brass is a better match for heavy gauges or high-end coaxial cable.
- Although solder terminals are the most common way to connect wire to the RCA plug, there are other methods. Some connectors crimp onto the wires or use set screws. Connectors intended for coaxial cables are sometimes designed to slide between the layers of wire and insulation. If you aren't prepared to solder your own connectors, staff at your local Radio Shack can advise you which plugs use these alternative connection methods.
- A soldering accessory such as Radio Shack's "Helping Hands" (catalog number 64-079) can simplify the process, using alligator clips to hold your wire and connector in place. This frees both of your hands for soldering.
- For better durability and a more finished appearance, you can slide a short piece of heat-shrink tubing over the section where the plug's outer shell meets the wire. Shrink the tubing into place with a heat gun.
- Take care not to nick the core wire of a coaxial cable while you're removing the white inner insulation. If you cut most of the way through, then twist off the piece of severed insulation with your fingers, you'll minimize the risk.
- Soldering irons and melted solder can cause serious burns. Handle your soldering equipment with care and have a soldering iron holder or designated heatproof surface near your workspace so you can safely set it down.
- Solder fumes can be toxic if inhaled. Work in a well-ventilated area and avoid breathing the fumes.
Items you will need
- Two-strand speaker wire
- Wire cutter/stripper tool
- RCA plugs
- Rosin-core solder
- Pencil-type solder iron, with a fine tip
- Flexible coaxial cable
- Sharp knife or coaxial cable stripper
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