Installing the PAM8302A audio amplifier in a Game Boy Advance
It will be helpful for you to know the current draw of your current modifications in order to gauge if this amplifier mod will overwhelm your system. The current draw of the PAM8302A is dependent upon multiple factors, including supply voltage. See the datasheet, page 5, for details.
Parts and materials
- PAM8302A amplifier module
- 2-watt 23mm speaker
- Hookup wire
- Desoldering wick
- 3M VHB (thin) or other double-sided tape
Lets get acquainted with the PAM8302A… it has 7 solder points, and they’re all straight-forward with what they do… here’s a diagram:
The ShutDown pin (SD) on the board isn't used in the Game Boy Advance installation, as the way audio works on the GBA means that connecting the shutdown pin with a 10k-ohm resistor to pin 5 of the headphone jack doesn’t actually turn the amplifier off. The explanation as to why is fairly in-depth - suffice to say that we have looked into this and there is no simple solution to the situation. The only impact is that the amplifier power will still be on during headphone usage, even though no sound will be playing.
Placement on the board for the 8302A is a very convenient spot just above the volume dial on the Game Boy Advance. The following mockup shows the placement for the 8302A module:
Placement is interesting since it sits on top of the things you’ll need to be hooking it into, so insulation for the amplifier connections is going to be key in this whole process. See the next diagram, below, which shows the audio pins and the regulated voltage pins as well:
What we’ve found helpful is to attach the amplifier wires first, leaving ‘just enough’ wire attached to each point that you can solder it to the board points shown above.
- With the console still assembled, start it up to ensure everything is working - ensure the volume is all way up and that you hear the startup ‘chime’ when the console it tuned on. If everything is working well, then continue…
- Desolder the speaker from the main board
- Use desoldering wick to desolder the two points where the speaker wires are connected to the main board. Desolder the wires from the stock speaker itself, too, as we won’t be needing the speaker by the time we’re done.
- As shown in the diagram here, just left of capacitor CP4, you’ll need to put a touch of solder to join just the tops of the two points - you won’t need much. This will be our positive (+) connection point.
- The top of capacitor CP4, the one just mentioned above, has it’s negative connection on the top - use your flux and add a touch of solder here as well… this will be for our ground (-) connection.
- Next up is the PAM8302A itself. Using the hookup wire you’ll want ‘just enough’ wire to where you can work with the PAM8302A board and the connections that will be made to points underneath it. Four inches should be enough to work with and not be excessive when the installation is done.
- Get power to the board
- Solder the wire from VIN on the PAM8302A to the positive (+) point we prepped on the GBA logic board.
- Solder the wire from GND on the PAM8302A to the top of capacitor CP4 as shown in the logic board diagram.
- Get audio to the board
- On the left side of the PAM8302A board, wire A+ to the top connection of SP1 (the audio outputs).
- Also on the left side of the PAM8302A board, wire A- to the bottom connection of SP1.
- Get audio from the PAM8302A to the 2-watt 23mm speaker
- On the right side of the PAM8302A board, solder + (amplified audio out) to one of the speaker points.
- Also on the right side, solder - (amplified audio out) to the other point on the speaker.
- Note: Polarity for the speaker isn’t important for this installation - it will work either way. If the speaker you’re using has designated + and - then follow that, but otherwise just ensure that + and - are not wired to the same point.
- Test it!
- Before we fully insulate the board and connections, lets test it to be sure things work. Put the console back together but without screwing it together in order to get batteries into the unit to test. Using the volume dial, turn up the audio to max. As soon as you turn on the console, you should hear a much louder startup chime now that the amplifier is hooked up, powered, and volume set to maximum.
- Test successful? Insulate it
- Reopen the console and insulate the bottom of the PAM8302A by covering the underside with the 3M VHB or double-sided tape. Then place the board as shown here:
- Close up the console - you’re done!
If you run into issues, double-check your solder joints for connectivity, powering down the console and going step-by-step to see where a connection perhaps has failed. Another common thing to check would be that the PAM8302A is getting power - set your multimeter to DC Voltage and test across the power pins on the amplifier to measure how much power the amplifier is getting… that voltage needs to be between 2.5V and 5.5V in order for amplifier to operate.
- PAM8302A datasheet (see page 5 for current draw)