Well it was that time of the year when the weather was nice and people go out for a barbeque. But I was always missing the decent sound out there in the green. So there it was, the idea of a beatbox that can kick some serious sound and move some air. But i was looking long for a decent case and was considering building my own form scratch, but than I found one with a whole lot more personality to it. An old Grundig Bandmaschine (reel to reel deck), made out of wood with a nice classic look to it. That's when things started to take shape. Well now it features a 4X150Watts car-amp with 2 attachable Subwoofers and an ATX powersupply.
Step 1: Case Preparation
The old Grundig Bandmaschine TR 40 was still in good shape on the outside, just the mechanics didn't work at all anymore. So no bad feelings for stripping it down. Well in the end I regret throwing away all the buttons, cause I could have used them on the beatbox, but well that happens.
I cut out a 12mm board to house the speekers ( 100mm max 120Watt) and they sit pretty close together but that is necessary, because it is going to be pretty grammed in there. I did cut off some of the the fake leather to make the glue stick better for the board. Glued in the board stiffens the whole case.
Step 2: Power Supply
Between the speakers I glued some wooden pieces to carry the amplifier, but more to that later. As a power supply I used a computer supply. Well I tried one before but it was too weak. Because the amplifier need some 10A on 12Volt I had to get a stronger on.
The powersupply finally used has 300 Watts and pumpes out 15 A on 12 Volt which should give me enough flexibility. Further than that I desoldered a lot of the cables I didn't need. I only need 2 yellow (12Volt) cables, one red ( 5Volt) cable, the green (on/off) and 4 black (ground) cable. It sits at the bottom of the whole case. I turned the airflow the other way (flipping the fan), so it sucks in air through the old bottom connector bracket, which I widened to get onough airflow.
To get the power supply going you have to attach the green cable to a black cable. But often the Powersupply checks if it has a load and will shut off if it notices that there isn't any. So I joined a 5Ohm resistor to the 5Volt cable and a black cable, and the power supply keeps on running. But the resistor get's quite hot so it is joined to the fan outlet to cool it with air. Be extremely carefull when handeling an opened power supply, always disconnect the power cord.
In the corners of the case I glued 4 threaded rods to hold the top piece later on.
Step 3: Amplifier
I ordered a amplifier from ebay pretty cheap. It's aluminum casing was to big for my case so I took it apart and attached some old pentium2 coolers without the fans(cheeap on ebay). The whole assembly sits on a board which I screwed on top of the brackets I installed in the step earlier. To be able to use the volume and bass/treble controls when it is installed in the case, I desoldered the pieces and extended the cables. So I was able to install the the adjusters on the top corner of the case. It was a hell of a mess with some 36 cables.
I will be able to adjust the vol/treble/bass seperate for the two channels in case I only take one subwoofer with me. Installed in the case everything fits just perfect, but it's getting already pretty crammed in there.
Step 4: LED Sign.
Well a decent beatbox definitely needs some light to it. So considering what was given I came up with the idea to install a sign writing on the side of the case, using the already given holes around the case. So when the light is turned off, the writing is not to be seen.
To achive this it was eather using some 120 leds or doing some fibre optics which I could get my hands on. So it was down to the fibre optics. I drilled the holes, a lot ot fhem. Glued in the optics with hotglue (let it cool down a bit on the tip of the hotgluegun, or it will melt your fibre optics) and bundeled them to be lid by 5 leds. I made a special bracket to hold the leds in place.
Step 5: Finishing Touches
Well for the final touches I had to install 2 crossovers. And joined them to the 2 speakon connectors (subwoofer) on the side of the case. Well now it's really full in there, but it still has enough place for airflow (in through the former pc powersupply outlet and out throgh the top where the old speaker used to sit). The other 2 connectors are for being able to run it of an external battery pack (12 Volt 18Ah) which you get from car jumpstarter. I also put 2 chinch connectors to the front to be able to attach a mp3 player. The player and the cable tucks away nicely in the in the pocket when closing the lid.
Well and thatÃ?ÃÂ´s it. Took me about 4 Month to finish it all together. Hope to give you some inspiration for your projects. Some more stuff on my side, that still needs documentation:
My hack page.