Multipurpose Audio Amplifier

Introduction: Multipurpose Audio Amplifier

Interface your iPod/MP3 Player, PC, Portable Radio and lots of other devices to this Portable Audio Amplifier! Plugs right into the stereo headphone jack on your device.

The Multipurpose Audio Amplifier was designed by BrandonC. You can get the parts from Gadget Gangster. Here's the schematic. If you'd like to gather the parts yourself, you'll need the following.

Parts list

  • 1x20 ohm resistor
  • 5k potentiometer
  • 22Ga Hookup wire
  • Gadget Gangster project board (boss board)
  • .1 uF Cap
  • Jumper wire
  • 4xAA battery holder (and batteries)
  • 3.5mm Audio Connector
  • A nice 8ohm speaker
  • And an LM386 Audio Amplifier DIP

You'll also need a soldering iron, solder, and wire cutters. Build time is about 20 Minutes and is an easy build.

How to Use It

Usage is super-simple - just plug what you want to amplify into the 3.5mm stereo jack, and control the volume with the knob. Get started building - go the next page for step 1.

Step 1: Jumpers

Start with the jumpers;

Bare jumpers at:
D (N7:M7)
E (N9:M9)
M (G9:F9)
N (O28:O29)

Red jumpers at
H (F16:D16)
K (C14:C12)
L (F10:D10)

On the back of the board, use a bit of hookup wire to connect D11 to M8

Step 2: Everything Else

Take a bit of hookup wire, connect one end to one pad of the speaker, and connect the other end of the hookup wire to H10. Use a bit of hookup wire to connect the other pad of the speaker to F18.

Add the LM386 IC between 7and 8, J and K

Add the Capacitor (J10:J13)
Resistor from H13:E13

The potentiometer goes in the area marked [Pj]. the headphone jack goes at [Pk].

Lastly, take the battery box, connect the red wire to E6, the black wire to F8.

You're done! Enjoy the tunes!

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    What is the output?
    You say 'a nice 8 ohm speaker' but nothing about how many watts @ X ohms


    11 years ago on Introduction

    Mabye You can answer a Q.
    I have ac/dc nexxtech amplified speakers. alone not attached to anything else.
    I figgured that if I use a 1/4'-1/8" reducer to the"mic" input, I could play my "non battery" guitar through this.
    Running on AC, I put my "plug" into the mic hole, and get zero sound..
    Do I have to preamp this, or what did I do wrong?
    Thanxs for any opinion.
    RJ Canada


    12 years ago on Introduction

    I was expecting a standalone build, but this is cool too for people who own one of these boards!


    Reply 12 years ago on Introduction

     You could easily convert this into being soldered if you knew how to work the board..luckily ill teach you
    everything going across is attached so if you had a wire in pin A it would be connected to pin a but not pin E or F and this is true for all the "sections"
    so if you had a pin in ABC and D then you would solder those four wires together if you had a pin in E then you would solder it to G and same is true with F you would solder it to H this is true for all sections on all
     -breadboards- (thats the name of them) they are great for testing where you may need to change a wire so you dont have to solder until you are ready