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 This instructable is for a cigar box guitar amp, powered by a 9V battery, that I built around the MintyAmp circuit board found on MintyAmps.com. The entire cost was under $30, but could be less depending on what parts you already have laying around. 

Step 1: Materials

-1- Cigar Box (mine was about 9x9x2 inches with walls thick enough to stay sturdy) ($3)
-1- MintyAmps Base Model (assembled) from mintyamps.com/store/index.php  (7.45 + shipping)
-2- small speakers (mine were about 2.5 inches in diameter taken from a cheap set of computer speakers) ($1)
-1- SPSD on/off toggle switch ($2 or so?)
-1- Volume knob/ potentiometer with as low resistance as possible  (free because I already had it)
-1- mono 1/4 inch jack  ($2 or so ?)
-1- 9 volt battery connector ($2 for a pack of 5)
-1- 9 volt battery (free with circuit board)
-2- 9 volt battery holders ($1.50 for pack of 2)
- extra wires (free, take them from anything)

Step 2: Tools

-Drill
-Drill bits in sizes matching that of jack, knob, and switch and a smaller bit for speaker grill
-Soldering iron + Solder
-Hot Glue Gun + Glue that will work on wood
-Screwdrivers
-Pliers
-Ruler
-Pencil
-Sandpaper

Step 3: Box

 You'll want to plan where everything will go in your box before building anything. Make sure that your knob, switch, and jack will have clearance inside the box when the cover is closed and everything is installed. The walls of my box were also a bit thick for the depth of the jack and knob, so you may have to do some counter-sinking to get the nuts to fit onto the threads.  

When you have figured out everything's placement, holes can be drilled. 

For the speaker grilles, I traced a circle around the speakers, then used a ruler to draw a 1/4 inch grid inside these circles, then drilled a small hole at each intersection of this grid. I don't have any pictures of this but I hope that this description makes some sense.   =P

Around this time I also mounted the Battery holders inside the box. I chose to put 2 in so that one can hold a spare battery, since I had extra space anyway. 

To attach the speakers to the lid of the box, I put a few dabs of hot glue on the rim of each speaker, stuck them down, and then added more than enough glue all the way around the outside of the speaker. 

Step 4: Wiring

 If I try to explain the wiring for this I can only imagine I'd end up causing more confusion.  =P

The site I purchased the circuit board from, Mintyamps.com has a free downloadable PDF file with schematics, pictures and descriptions explaining how to put together all of the electronics. 

I am in no way affiliated with with this site, they were just very helpful and friendly during my purchase from them, and even included a free battery and battery hook-up. 

Step 5: Play!

 I'm really happy with how my amp came out. The sound is surprisingly good and loud, and the battery life seems to be holding up well. After over an hour of continuous use, I used a battery meter to check the power remaining and it had barely gone down. I plan on buying some rechargeable batteries this week for the amp. 

My only problem is with the knob I used. For one thing, it was originally a balance knob from a stereo, so it is backwards (counter-clockwise to turn the volume up). The real problem is that the knob produces zero volume for 90% of it's full rotation and the sound only comes on in the last couple degrees of turning. 

I'll probably replace it with a more suited potentiometer and be good. 

Thanks for reading and feel free to comment with any questions!
Does this work with any kind of speakers?:P
My husband bought me one on line and I love it. However, I can't wait to try and make my own. THANKS,
I'm amazed with the design, i love the wooden speaker hole/gril effect. <br> <br>Can you add a gain control somehow??? <br> <br>I've started a blog for my first CBG build here <a href="http://www.dirtyguitarguide.com">dirtyguitarguide.com</a>
Hi! Great Instructable! I am planning on building my own guitar this week and now I think I might just build this too! The only question I ask, is what is the point of the circuit board? Can I make it without that? (I am trying to get everything in one trip and don't really want to order anything) Thanks!
The circuit board is the actual amplifier. If you know how to wire up an amplifier circuit from scratch then I guess you wouldn't need it, but that's beyond my abilities. I think on the site I linked to it lists all the specific pieces that are on the board. You could probably get them all at radio shack and wire it up yourself.
Hello,<br /> <br /> This seems interesting to make.<br /> The link for the &quot;MintyAmps&quot; show a empty page, which one can a use instead?<br /> <br /> Thanks.<br /> <br /> David<br />
&nbsp;Well it looks like they don't have the Pre-assembled PCB on their site right now. I'm assuming it will be back eventually, but if not, the link to the kit (Which includes the base PCB and all the components, just not assembled) is here.&nbsp;<br /> <br /> <a href="http://mintyamps.com/store/index.php?main_page=product_info&amp;cPath=1&amp;products_id=2" rel="nofollow">mintyamps.com/store/index.php</a><br />
Ho, Thanks, I'm not really good for all that electronic things.<br /> I'll wait for the assembled one.<br /> <br /> David<br />
&nbsp;I actually just finally got an electric too, so I'll record and post clips of both within the next few days. Great idea!
You said that you use this with an acoustic?&nbsp; Any chance you could post a sound clip?&nbsp; Also, what do you suppose it would sound like with a bigger speaker and larger box?&nbsp; Any ideas?&nbsp; Thanks.&nbsp; Nice project.<br />
Quite nice, how does the sound alter open/shut?<br /> <br /> L<br />
&nbsp;The sound is a little bit more full when the cover is closed, I didn't think the small box would give too much resonance, but it does enough.&nbsp;<br /> <br /> The real difference between open/ shut seems to be feedback. I've been using an&nbsp;acoustic&nbsp;guitar with a peizo-electric pickup which feeds back easier than most, and with the cover closed, I can bring the sound-hole of the guitar to within a foot of the speakers before it starts to feed back. With the cover open, I have to back up to about 3 feet or I get some unwanted feedback. &nbsp;<br />
Thanks, that's interesting. Box closed you've got some effects on the back-sides of the speakers, copy and past this info' into step 5?<br /> <br /> L<br />
&nbsp;Thanks! I've been playing with it some more the last few days, and surprisingly, the battery is still holding up extremely well! It seems that you can easily get several hours of continuous use out of one 9 volt battery! This is even with 2 speakers wired in parallel, as opposed to the circuit's intended single smaller speaker.&nbsp;
Very cool.&nbsp; Thank you for including the info and battery life.&nbsp; I definitely going to give this one a try.&nbsp; I recently downsized at home and have been looking for an &quot;interestng&quot; amp to replace my full size amp with.&nbsp; <br />
Now that is a sexy amp!&nbsp; It definitely has the coffeeshop/museum feel.&nbsp; Very nice idea!<br />

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