DIY Bluetooth Center Speaker with TPA3118 Amp

If you're interested in making a Bluetooth card speaker using a center speaker, you might want to check out this article.

You'll need a TPA3118 amplifier board that supports radio, U-disk lossless playback, full Bluetooth functionality, and even a karaoke feature. It can decode lossless audio like FLAC and WAV. The panel dimensions are 195×93.2×10 mm, with hole spacing of 183×72.4 mm and hole diameter of 3.8 mm.

If one of the resistors on your amplifier board isn't soldered properly, causing the op-amp not to work and resulting in low sound, or if another part of the power supply has a poor connection and produces intermittent silence, you can start repairing it.

You'll also need to prepare a composite board for the casing. You'll need a center speaker—usually, a center speaker has one tweeter and two mid-low units. You can also prepare one with two coaxial units. You'll also need the speaker itself; even if the bass tube is damaged or the coaxial tweeter is broken, the speaker's magnet is large enough that the sound quality is still decent for listening.

The installation process is quite simple. You can cut a hole on top and install a 12V 5A power board inside. If you don't have a higher-power board, it's okay—the speaker is 8 ohms, and the board doesn't deliver that much power, so there's no need to prepare a new power supply.

The finished look is shown in the picture above.

You need to drill a hole in the speaker's binding post to run a 220V power cable, and you can also install a power switch. Leave one hole for connecting an external radio antenna.

If you're not happy with the appearance, you can re-cover it with black walnut veneer, and then install a UV meter and nicer knobs. Mount the amplifier board on the back panel.

After installation, the sound quality is okay, except the bass is a bit weak. Still, it sounds better than most small Bluetooth speakers.

Finished.