How to Wire a New Speaker Into an Old Radio

by Jeff Grundy

While most antique radios don't produce the fidelity of modern sound devices, they certainly offer a charm and level of craftsmanship that is hard to find in today's digital world. During the early and mid-1900s, when radio production was at its peak, the radio was not only an audio device but also a piece of furniture often showcased in the home. Consequently, many antique radios are treasured heirlooms. If you have an antique radio with a blown or defective speaker, you can breathe new life into the unit by installing a new driver or wiring an external speaker box.

Unplug the radio from the electrical outlet if you have not already done so. Set the “On” switch to the “Off” position. Allow the tubes in the antique radio to cool and discharge at least eight hours before opening the enclosure.

Use a screwdriver to remove the retaining screws that secure the rear panel of the radio. Some older radios are fastened with twist-tabs similar to thumbscrews instead of regular wood screws.

Remove the screws that secure the tube and transformer board if the components prevent easy access to the speaker. Slide the board out of the enclosure until you can reach the speaker comfortably.

Remove the crimp connectors for the speaker wires if the connection uses them. If the speaker wires from the tube board to the speaker have a solder connection, use a pair of scissors or small wire snips to clip them just below the terminal connectors on the rear of the speaker.

Loosen and remove the four screws that secure the speaker to the side or face grill on the radio. Remove the speaker from the radio.

Purchase a replacement speaker that meets or exceeds the power handling capabilities of the old one. Most tube-powered antique radios produce relatively modest amounts of power, so most modern drivers should be able to hand the wattage output without issue. Nevertheless, check the power rating on the rear bracket of the speaker or on the back of the magnet, and ensure that you purchase a speaker that can handle the wattage output of the antique radio. Also, try to purchase a speaker with mounting-screw holes that align as much as possible with the ones on the defective unit. If you are unable to find a speaker with mounting holes that line up with the screw holes in the enclosure, purchase a speaker slightly larger than the one you need to replace. This will allow you to mount the speaker using short, self-tapping wood screws to create new screw holes.

Use the wire strippers to strip away about one-half inch of shielding from the ends of the two speaker wires inside the radio enclosure.

Align the mounting holes on the new speaker with the screw holes inside the radio cabinet. Reinsert the mounting screws you removed from the old radio and tighten them with the screwdriver. Alternatively, align the slightly larger screws on the new speaker so that the mounting holes face bare wood. Use self-tapping wood screws to secure the speaker against the grill space.

Plug in the soldering iron and wait for it heat up. Use the soldering iron and flux to solder the ends of the stripped wires to the terminal connectors on the rear of the speaker. Solder the black or solid-colored wire to the positive (+) terminal on the speaker. Solder the red or wire with the thin stripe to the (-) terminal.

Realign the tube and transformer board if you removed it to access the speaker. Secure the board with the retaining screws.

Replace the rear panel and secure with the retaining screws. Plug in the radio and turn the power selector switch the “On” position. Use the radio as you normally would.

Tips

  • If you don’t have a soldering iron or don’t feel comfortable soldering the small speaker wires, you can use crimp connectors to make the connections to the new speakers. To do this, slide the open end of the crimp connector onto the stripped end of the wire, then use the crimping tool to compress the connector. Compress the crimp connector with the tool until it grabs the bare wire securely. After you crimp the connector, you should not be able to pull the speaker wire free. Place another connector on the other speaker wire, and then push the terminal connectors from the wire onto the thin, small terminal plates on the rear of the speaker.
  • If you cannot find a suitable replacement speaker or would like to leave the original in its place, you can wire an external speaker box to the old radio. To do this, clip the speaker wire connections to the old speaker, then crimp butt connectors on to both wires. Feed thin-gauge speaker wires into the radio cabinet and connect the wires to the open ends of the butt connectors. Crimp the connectors to the external speaker wires, then connect the other ends to an external speaker box.

Items you will need

  • Screwdriver set
  • Scissors or wire snips
  • Replacement speaker
  • Wire strippers
  • Soldering gun and solder flux (optional)
  • Crimp connectors and crimping tool or needle-nosed pliers (optional)
  • External speaker and speaker wire (optional)
  • Butt connectors

About the Author

Jeff Grundy has been writing computer-related articles and tutorials since 1995. Since that time, Grundy has written many guides to using various applications that are published on numerous how-to and tutorial sites. Born and raised in South Georgia, Grundy holds a Master of Science degree in mathematics from the Georgia Institute of Technology.

Photo Credits

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