Boom Box – an amplified speaker

A picture of my Boom Box. Scattershot looks on in approval.

I saw this great article over on Make last month about making a monobox. Basically taking a box and putting a speaker and a small amplifier circuit inside. Put an input on the outside for any mp3 player to plug into. I also wanted a volume control so I could use this as an amplifier for anything, not just an mp3 player.

I tried lots of different speakers and 3 different amplifier circuits.
I tried lots of different speakers and 3 different amplifier circuits.

I made the lm386 circuit but I just wasn’t happy with the sound. So I found a 7 Watt amplifier kit from Velleman. I had some 4 ohm 6 watt speakers laying around that I robbed from a broken karaoke machine I found on the side of the road.

$10 speaker.

I also had this little $10 boom cube as-seen-on-tv that I picked up at walgreens awhile back. It’s rechargeable, has an on/off switch and is a cube. It sounds terrible.But I thought it looked cool. So I used it for my inspiration for the Boom Box.

First I got to work at making a box out of 3/4″ MDF. I made four sides and then glued them together to form a box. Then I framed out the inside to have something to screw into. I also drilled a whole in the top for my handle to slide through. Right now it’s a bungee but I may change it to something else.

Primed and painted the whole thing. Used Rustoleum hammered finish spray paint.


IMG_2114 IMG_2113

On the back there’s a 1/8″ stereo input, a combo on/off/volume switch, and a power connection so that I can recharge the batteries inside when I change them to rechargeables.

Right now there are alkaline batteries in there because I didn’t have 10 AA rechargeable batteries laying around. The circuit has a wide voltage range so the difference in voltage won’t affect it much.

And there you have it! The Boom Box!



  1. […] Inspired by the MonoBox Powered Speaker project, maker Tony Barnhill ditched the LM386 circuit in favor of a 7W Velleman kit, driving a speaker salvaged from a karaoke machine he found on the street. He built everything into a thick, 3/4″ MDF box, and stenciled the grille with his boomin’ project name. You can read more about his build over on his blog. […]