Step 1: Parts List/ Tools
-beer crate (I used a 11x 0.5l Carlsberg beer crate because it seemed to be the best for this project but you can basically use everyone you want to)
-amp (I got a Kinter MA-700 for 15€ here in Germany but every class-D amp with 5-12v and up to 5a should be okay)
If you want to make it inexpensive, I recommend using a 5v amp board with a PAM8403 chip (just search for it on the Internet). You can power this one with 3 normal AA-batteries or a normal USB-powerbank.
-speakers (I used some old home audio speakers, full-range speakers would be the best but car speakers or just some old ones you already have are okay, too)
-powerbank/battery (if you have the possibility get one with a 12v output, I already got one with a 5v USB output at home so I needed a voltage transformer - I don´t recommend that version but it seems to work.)
UPDATE: I have purchased a 12v powerbank, that increases the sound quality and especially the maximum volume a lot.
-audio cable (3.5mm to RCA), speaker cable and power cable (depending on the output of your powerbank)
-some wood (I just used some old wood that was lying around)
-spring loaded latches (I hope this is the right word for what I mean :D)
-screws, nails, nuts
[-optional: bass reflex tube or an old plastic tube]
-drill and drill bits
-grinding machine or sandpaper
-maybe a chisel
Step 2: Preparing the Crate
I also drilled some holes for the amp and cut a hole to get the powerbank in and out. If you aren´t really shure where exactly the amp will be leave this step out and do that later on. I also cut in a small hole for the bass reflex tube because I made the speaker housing a bit too large.
I took the picture at a later date and because of that the amp is already built in and the latches are already mounted.
Step 3: The Amp and the Battery
My amp, the Kinter MA-700 has quite a good sound and is quite loud, too. If you need more volume you could use a better class-D amp but that will shorten the battery lifetime and it will get the boombox a lot more expensive, too.
Step 4: Speakers and Speaker Housing
I could use some parts of the original housing so I didn´t have to cut the holes for the speakers. I just took my saw to make all parts I needed (4 sides, top and bottom). I built in the speakers on the smaller sides of the housing because my crate had holes in the smaller sides and I wanted the speakers to fit behind them. After I had mounted the speakers with a few screws I took some nails to put the parts together and then put screws in the corners to make it more stable.
I drilled a hole at the bottom of the housing where the speaker cables come out because the amp is under the speaker housing in the crate.
Last but not least I made a hole in the side of the housing for the bass reflex tube (which is a normal PVC tube in my case :D) and painted it all black with some spray paint.
I´m no expert in this and I´m sure there is a better solution for this but I´m quite satisfied with the sound so I´ll just leave it as it is. But there are already some instructables on how to build speakers so you should find something there if you´re interested in this.
Step 5: The Lid
Step 6: Putting It All Together
I found out that the speaker housing fit right into the crate on the 4 sides and was lying straight on the amp. To make it a bit more stable I screwed some blocks of wood on the wooden plate, a bit higher than the amp. Because some of the were a bit too short I put some coasters on the wood. Now the speaker housing lay right on the wood and the coasters, a few millimeters over the amp.
I then mounted the latches on the lid and the crate. And the final step was to mount the cap for the hole to put the battery in and out using a screw on the outside and a nut on the inside of the crate.
And then Carli was finished :)
Step 7: Further Thoughts
- I want to add LED lighting to the crate with a USB ledstrip
- I want to add a bluetooth receiver so you don't need to plug your phone directly into the boombox