Tuesday, June 13, 2017

Making a Cigar Box Amp

First things first:
  • I don't play guitar.
  • I didn't build the electronics or understand how they work.
  • I didn't solder a single connection on this.
  • I didn't build the "cabinet."
  • I didn't even smoke the cigars that came in the box.
  • I know... I know...it's not a toy and this is a toy making site.
But other than that, I made it!

So this project started about 4 years ago when I was talking to one of the more clever freshwater crustaceans I've ever met - Crawfish his-self over at Crawls Backward When Alarmed.

Among his many talents, he plays guitars and builds and fixes amps (and SAABs.) I had suggested that if he made the innards for an amp, I'd try and make a vintage looking radio cabinet to house it in (like a Tombstone or Cathedral style table top radio from the 1930's.)

He very generously put together his version of an amp called "The Noisy Cricket" and dropped it off with me to do my bit. Details on his build can be found here and here.

His final assembly and the original chassis can be found here.

So, if you have any questions about any wires, inputs, electrical thingies or the sounds this project creates, please check out his site.

Like far too many of my projects without deadlines, the Noisy Cricket (aka Crawfish Instruments Model 386) sat on a shelf for a couple of years. That is until Mrs Toy Making Dad's birthday rolled around this year. She has an acoustic/electric guitar but no amp and a husband who likes making stuff. Seems like a no brainer.

So I opened up the Noisy Cricket and started taking inventory of what needed to go where. When I realized how small the components were and the fact that I wasn't going to re-solder any connections, I decided that the box could be pretty small. Then it occurred to me (and a zillion other amp DIYers on the web) to use a cigar box as the chassis.

My local beer/wine super store sells empty cigar boxes for $.50 a piece. Crazy huh? I always check the shelf to see what I can find and honestly, I've gotten some real gems there. I've made several "Shut The Box" games out of them and use them for all sorts of classy storage around the shop.

I looked for a box the speaker would fit in and then worked back from there. I found this neat ONYX box. I couldn't make a box half as solid for 20 times the cost.

It just needed some stickers removed and some superfluous wood lining taken out. (I needed the walls to be thin enough for the various switches to fit through.)

Next up, a trusty grade school "quality" compass to draw the circle out for the speaker. (That is a tool I really need to upgrade at some point. What will the editors at Better Homes and Toy Making say if they ever drop by?) I drilled a pilot whole in it and then used a coping saw since I couldn't use my scroll saw on the box lid. (It won't open flat while still attached to the rest of the box, but I could deal with that on a workbench.)

This is it after I finished. Although I gotta be honest, I pretty much butchered it with the coping saw. It looked bad until I cleaned up the circle with a drum sander attachment on my rotary tool. Just need to be patient, take little cuts and cut to the line.

As an aside, I have a circle cutter that I inherited from my parents. I was going to use that but when I put it in the drill press, I found that the shaft was bent and the experiment turned pretty scary pretty fast. However, note the $.50 cigar box holding all of my parents' Allen wrenches. Were they collectors and they just never told me?

So the next part was to line up the connecting nuts and bolts and drill those holes to anchor the speaker to the box. That then let me see exactly how much space I had to arrange my connectors and nobs without the speaker hitting them. (I had gotten a pretty good idea before I started but you never really know until you start cutting stuff up.)

So this amp is powered by a 9v battery or a DC "wall wort" power supply of similar voltage. The battery needed to be on the bottom of the chassis so as not to dangle. I then drilled the holes for the guitar cord input and the speaker out jack along with the external power connector. I put these down the side of the box with the hinges. I countersunk the holes using a Forstner bit so I could get sockets around the retaining nuts.

The top of the amp has the On/Off switch, a power indicator LED, Volume, Tone and Gain controls. I lined these holes up so that they would look centered with the lid closed.

The base of the On/Off switch required me to chisel a little inset on the inside of the box so he top would fit through. The countersinks on top were to allow for the volume, tone and gain knobs to fit in there just right. Once again, I used a Forstner bit for that.

Well, as often happens when you are clueless, I managed to disconnect a wire or two and had no idea how to fix it. For example, this do-dad came disconnected from the board thingie and if I was gonna use a melty stick on it, I figured I should actually know where it was supposed to go. (Sorry for all the technical jargon.) So, I popped into my exceedingly sensible vehicle and paid a visit to Crawfish's Electronic Dungeon for the final touches.

He got to work replacing the speaker with an upgraded one he had recently acquired and wanted to test and grabbed a schematic to see where the do-dad was supposed to connect to the thingie. He heated up the melty stick and a few puffs of mostly non-toxic smoke later, we was in business.

We switched out the blue knobs for these grey ones and he added a battery clamp and some Velcro to hold down the board. Basically, the only time it will ever be opened will be to replace the battery so we didn't make any efforts at wire management.

As they say.. the proof is in the playing.

Since I can't play, Crawfish gave it a test :

And he worked out the Kinks...

Anyway, not something I could have done on my own, but something that I think most people could do with a few drill bits, a box ,some patience and a buddy who knows what the heck he is doing.


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Just Saying...

While we don’t necessarily need more objects, we just might benefit from more making.
- John Dunnigan


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Regular guy who likes to make stuff who lives with a very patient wife, three daughters and three cats.