This is a small powered amplifier that plugs into a 1/8" stereo jack and accepts the same. Many people know nothing about amplifier circuits and would have no idea how to make one, so why don't we let a company make the circuit, and then just tweak it to meet our needs (So admittedly one does need to know a little about electrical circuits, speakers, and soldering).
This is the perfect thing to provide the extra energy needed to power larger speakers with a portable audio device without severely draining battery power. This pocket amp also allows for louder audio through headphones or small speakers. Time to blow out those voice coils!
Step 1: Hunt and gather supplies
For this project you will need:
-A small hearing amplifier, often called a personal amplifier or advertised as spy hearing (I used a
Radioshack brand "amplified listener" )
- Stereo headphone cable with 1/8" jack
-2X AAA batteries (or whatever your particular model requires)
-Connecting wire, scrap wire
-Hot glue, silicone or epoxy
-Drill and bit slightly larger than the the width of your headphone cable
-Audio source and headphones to check your progress.
Step 2: Void the warranty
Using a screwdriver, unscrew all the necessary screws and pry the case open, remove the battery cover and get rid of any shielding (this does reduce audio quality but we need that space for some wires.)
Step 3: Check the microphones
Identify what parts are which and what wires go where. You will need to remove the microphones and use the wires leading to them as your input source
Step 4: Identiy your connections
After severing your left and right microphones, mark which connections go with which microphone: left or right.
Step 5: Wire the connections
Since someone else made the circuit, all we care about are the input and outputs, the output is already wired as a 1/8" headphone jack, and by soldering together the leads to the (now removed) microphones, red to red and black to black, we can then wire the circuit to our own input source
Here some of the wires attached to the board were too short, so I used a piece of scrap wire (yellow) to connect them.