Portable Amplifier

Portable speakers for your smartphone, electric guitar, and more! This portable amplifier from Trash Amps can be made from, just about anything. I made this Walnut enclosure for mine, but you can use anything from pop cans to mason jars.

I started out with a piece of Birdseye Maple 1" x 4". This will hold the speaker, and amp. I used a square carbide cutter to true up the side, and the face.

I used two pieces of double-sided tape, and a piece of plywood to remount it on the lathe in the chuck. I took two of the jaws out of the chuck so I can turn an off-center hole for the speaker. I cleaned up the face with a round carbide cutter.

Loosen the jaws of the chuck, and move the plywood waste block over 1/4" this will offset the speaker hole. Use a pencil to mark the speaker size, mine is 2". I used a parting tool to cut in 1/2" for the speaker.

Flip the piece over and remount using double-sided tape again, this will be the front. Turn down the front until the speaker hole opens up from the backside. I used a round carbide cutter for this. Then sand it up to 600 grit.

I used a piece of Walnut 5" x 9" for the enclosure. Mount it on the lathe between centers, and use a roughing gouge to true the piece up. Put a tenon on one end that will fit your chuck jaws.

While it's still in between centers, shape the outside of the enclosure to desired shape. I used a spindle gouge to do this, and the lathe is running at 2000 rpm.

Make a small recess for the face plate, and hollow out the inside. I used the #1 East Hollower for this. It's a small carbide cutter that reduces vibration, and less chance of catches. There are two different kits, so hollow out enough room for the kit you have.

I finished turning the outside with a spindle gouge, and sanded up to 600 grit.

This step is optional, and takes some practice. I loosened the jaws, and kicked the piece a little off-center in the jaws. Turn the lathe speed down, (I run it at 400 rpm for this step) and used a spindle gouge to bring it down a bit.

Remount in the chuck by expanding the jaws, and bring the tailstock up to help support it. Turn the tenon off, and sand up to 600 grit.

I made the base out of Birdseye Maple as well. The body is 6 1/2" and overall length is 18". I just tried to proportion the base to the enclosure. This may very on the size of enclosure you make. I used a bandsaw to cut it out, this can be done with a jigsaw too.

I sanded the base with a dual action air sander, but this can be done with a orbital sander too.

The kit comes with a templet for the power switch, and jacks. Find center of the speaker hole, using the templet line up the center hole in the templet. Drill the three holes out with a 1/4" drill bit, a forstner bit works best.

Drill the base and enclosure at a slight angle with a 3/4" forstner bit. This is for the mounting riser, (I used aluminum) but you can use wood if you like.

I used a wipe on finish for this project, it's beeswax and mineral oil.

With a chisel I cut a slot in the neck for my phone to rest. This can be done anywhere along the neck.

I cut a 3 1/2" piece of 3/4" aluminum tube for the riser, and glued it into the enclosure and base.

I mounted the amp and speaker using the supplied hardware. Trash Amps has a great step by step on there website for soldering the components to the board if you buy the unassembled kit.

In hindsight I wouldn't of used wood for the plate, it was very difficult to fit the amp. It's designed to be mounted to a thin piece of metal like a jar lid. I had to mount a thin piece of Walnut veneer on the front, because it was getting so thin. I really enjoyed making this project, and happy with the way it came out.