Introduction: Make Your Own Cigar Box Guitar / Mp3 Player Amplifier

I've wanted to create a Cigar Box Guitar and Amp for quite some time, and it seems like the Instructable Sound Hack and Battery Powered contestst were just the extra incentive I needed to give it a try.

This Instructable shows how to create a Cigar Box Amplifier, of course it can also be used as an MP3 player or Phone amplifier. I decided to build the amplifier before the guitar since it's certainly easier, but hopefully a Cigar Box Guitar Instructable will follow soon!

If you haven't heard of Cigar Box Guitars, you should check them out. YouTube has lots of videos demonstrating amazing sound from these 3 stringed instruments. 

Here's an example of a CBG in Action:

Actually they don't all have 3 strings, but hey this is about the amplifier anyway,
let's build one!

Step 1: Gather Tools and Parts

What's Needed for this Guitar Box Amplifier Instructable?
  • Cigar Box - I have a friend who occasionally smokes a cigar, he tells me they are all legal (at least somewhere in the world ;-) ). I noticed these can also be found at Yard Sales, on eBay and sometimes for free in Tobacco Stores.
  • LM386 chip based amplifier circuit - I got a kit for this from   (some sites sell pre-soldered kits as well) but you can likely make your own. Parts needed are: Potentiometer, LM386 Chip, Resistor, 2 Capacitors, 9V battery connector and Guitar jack.
  • 8 Ohm Speaker (I got mine from an old projection TV)
  • Switch (optional) - didn't come with the kit, but I thought it would be handy to save on batteries.
  • Wire
  • Miscellaneous parts for decoration, most important is something to cover the speaker, (I used the plastic which originally covered the speaker on the TV). Optional: Handle, Legs, battery holder, Something to keep the cover of the box closed, 
Tools Needed for This Instructable:
  • Drill 
  • Soldering Iron and Solder (unless you buy a pre-soldered kit)
  • Hole Saw (optional) to cut the speaker hole (or use a drill and Dremmel or X-Acto knife)
Now that you have your parts... 
Step One is to solder together the kit, as seen in the picture below. 
(It's a good idea to get a general feel for where all the parts are going to be installed before you actually start cutting wire and soldering. You'll notice I left way too much slack on my speaker wire)

Step 2: Install Speaker on the Cigar Box

Where Does Everything Go?
Since my plan was to use this as a Cigar Box Guitar Amplifier, I only needed one speaker and figured it should be mounted right in the center of "the front" when in use. Thus I sized up the center of the "bottom" of the cigar box. But that's just how I figured it would work best...I've seen other placements as well.
One possible issue I found with how mine is configured is the weight of the guitar jack can cause the box to tip forward.

I used an inexpensive hole saw kit ($8) and the biggest hole it made was 2 1/2" in diameter, just about perfect for the speaker I found.
I think you could easily mark the circle, drill a few holes on those marks and then cut the circle out freehand, especially if you are going to cover the hole with a screen as I did.

Step 3: Speaker Grill

It's Grilling Time:
I noticed many examples of material being used for speaker grills...also computer fan covers...I searched around my shop and couldn't find anything appropriately I figured ...just cut the grill from the TV where I got the speaker!
I did find some old brass colored bolts laying around that helped give it a more rustic/steam punkish style.
To make the grill the right size, I just put the plastic in a vice and used a basic hacksaw, then I smoothed out the edges on the bench grinder.

Step 4: Final Assembly

Optional On/Off Switch
Almost forgot, the kit didn't have a power switch and I didn't want to have to open the box and take out the battery every time I put the Amp away. So I found a switch laying around from an old fan. I snipped the red line of the 9V battery adapter and soldered the switch in place. Also battery related, notice the Battery Holder I fashioned out of a left over metal dryer vent bracing strap. 

Optional Legs:
I don't think legs are really necessary, but what the heck, it'll be fun...I was thinking of using dice for the legs, when I found some old cabinet handles and they looked like they would do the trick. I simply measured them out evenly, drilled 4 holes and screwed them in. 
I found it's handy to have an X-Acto knife to cut off some of the excess cardboard that builds up around the hole after drilling.

Optional Handle
Another piece of old "junk" laying around that I finally found a use for...a brass and wood cabinet handle. Just like the legs I drilled, cleaned up with the X-Acto, and screwed it into position.

Potentiometer (Volume Control):
for some reason I thought the side of the unit was a good place for the volume. Maybe because I wasn't sure what I was going to use for a control knob at the time. I still might switch the location of the Guitar Cord Jack with the location of the POT. I think I can do this with little rework ....but since I ended up using the red die for a control knob (simply drilled a hole in it and it's held in by friction), I think it looks fine the way it is (maybe if I find more retro "Chicken Head" control knob.

More Decoration
For the Switch and the Jack mounts, I found the brass left over from the porcelain handles (ie the legs) worked great! for some extra decoration. 

Guitar Plug Jack
Repeat again I say Repeat!

Step 5: Let's Test It Out (Video Included)

MP3 boom box anyone??
I had an adapter and cord that let me plug in a cell phone playing tunes from Sound Cloud (thanks to for their original Zombie Rock music). Works pretty well, only thing to do is figure out what to do with that bracket which is supposed to hold the box closed.
Here's a video of the Amp in action:

Things I learned on this build 
Measure twice, cut once (yeah I know it's an old one). I could have done a better job lining up the speaker cover and my first attempt at the handle wasn't quite square with the world.

Keep a Clean Workspace:
I was in so much of a hurry to do the final assembly on this that I left sawdust and bits of plastic left from drilling on the workbench...ended up scratching up the cigarbox this way...darn it...guess that adds character.

Hoarding is good
Well not really, but since I successfully used old junk parts on this project, I'm gonna have a hard time throwing stuff away...So maybe I should say Repurposing is good.

Already mentioned:
I found it's handy to have an X-Acto knife to cut off some of the excess cardboard that builds up around the hole after drilling.

Thanks for checking out this Instructable, Comments and questions welcome.
I hope it's helpful and you have fun and good luck on your projects.
(Please vote for this Instructable by clicking Vote in the upper right hand corner.)

DIY Soundhack Contest

Second Prize in the
DIY Soundhack Contest

Battery Powered Contest

Participated in the
Battery Powered Contest