Introduction: Make a Guitar/MP3 Player Amplifier From a TRASH AMPS Kit

About: I'm a French Canadian from Shawinigan. I just want to start it with the proof that nobody is perfect! I’ve produced free humorous woodworking videos for more than one year now. However, this is not my full ti…

In this Instructable, I will show you how to build a custom enclosure for a Trash Amps DIY amplifier kit. I used maple and walnut to create a big, chunky box amplifier with a cartoonish feel. You can use this little battery-powered amplifier to listen to music or play guitar — it’s your choice. Let’s get started!


  • Soldering iron
  • Screwdriver
  • Wire cutters (scissors will also work)
  • Miter saw
  • Table saw
  • Drill press or hand drill
  • Powered sander or sandpaper
  • Router (optional)
  • Masking tape
  • Pencil

NOTE: This project involves the use of power tools. If you are uncomfortable using these tools, DO NOT attempt to duplicate this project. Trash Amps kits can be installed in anything, from a custom wooden box (shown here) to a cardboard box or even a soda can. Please be safe.

Special thanks to Bill Livolsi at One Car Workshop for helping me write this article!

Step 1: Assemble the Kit

The Trash Amps kit does not come assembled, so you’ll need to do some soldering before it’s ready to go. Instructions are included, but here is a brief summary:

Solder the two 3.5mm AUX jacks, toggle switch, 5mm red LEDs, capacitor, and male headers to the printed circuit board (PCB). The headers will accept the battery cable and power the speaker.

Full kit instructions can be found here:

CAUTION: if you mount the capacitor backwards, it could explode when you turn on the amp. So don’t do that. Double check the placement of this part before you solder it into place.

Step 2: Make the Enclosure Parts

The enclosure will be a simple wooden box. I used 1” walnut and some 1/4” maple plywood, but any wood will do just fine.

The dimensions of the enclosure are entirely up to you. I built mine at 5” x 5” x 5”. To start, I cut down some 1” thick walnut to 5” wide.

I then cut 1/4” wide, 1/2” deep grooves (dadoes) into the top and bottom while the wood was still one piece. This will ensure proper alignment later. If you cut the pieces separately, there’s a chance they won’t align properly. It usually works out okay but better safe than sorry. Check the fit of the grooves using a piece of the panel stock. If it’s too tight, cut away slightly more material until you have a snug fit.

Using the miter saw, I cut 45 degree corners on each piece of walnut to make four sides of equal size. A stop block helps to ensure consistency.

Then cut 2 pieces of 1/4” maple plywood down to 4" X 4".

Step 3: Assemble the Enclosure

Lay out two strips of masking tape or painter’s tape. Place the walnut pieces along the tape so they are touching at the corners. Test fit the panels by folding up the sides and inserting the panels to make sure they fit. Once you know the pieces are all the correct size, add wood glue, insert the panels, and tape the assembly together.

Measure the diagonals of the assembled box. If they are equal, the box is square. If they aren’t equal, nudge them until they are. Let the glue dry. Go have a snack. Come back in a few hours.

Once the glue has dried, sand the sides using a belt sander, random orbit sander, or sandpaper. I rounded over the corners - this is optional. I also used a router to round over the front edge (also optional).

Step 4: Install the Amplifier

Cut the box open on the table saw. You’ll want to cut away roughly the first two inches of the box. Glue in some scrap maple pieces, 3” wide by 2” long, to help the top and bottom stay together. You can also use traditional box hardware (hinges and clasps) if you wish.

Using the template provided with the Trash Amps kit, mark out the locations of the LEDs and rocker switch. Also mark out the location of the speaker. Drill out these holes carefully on a drill press or using a hand drill.

Apply finish to the box before adding the electronics. I used wipe-on polyurethane.

Once the finish has cured, install the electronics using the provided screws, tuck away the wires, and close up the box.

NOTE: remember to charge the battery!

Step 5: Finished!

That’s it! Now you can use your custom amplifier to listen to music from your smartphone or plug in your guitar using a 1/4” to 3.5mm adapter. Enjoy!

Amps and Speakers Contest 2016

Participated in the
Amps and Speakers Contest 2016

Glue Challenge 2016

Participated in the
Glue Challenge 2016