The inspiration for this project came when I helped build a stereo amplifier mounted on a Budweiser beer keg. I thought it would be interesting to build a fully Bluetooth controlled amplifier, quite minimalist, highlighting only the power button.

From this idea, I began to design the device, which would be MDF laser cut, coated with wooden sheets.

At first I was thinking of putting the speakers on display, having a LED button in its center, until I found some interesting patterns on the internet. Hence I thought it would be interesting, rather than using apparent speakers, to use a grid with some laser cut pattern. So I made several sketches to find the one who would fit the project. The choice came after deciding to mount the featured amplifier board on a black acrylic piece, where I made some random circles, to break off the rigidity of the piece. So I thought, why do not follow this same pattern of circles of random diameters in the amplifier grid? I wondered this pattern would give a more dramatic effect to the design by combining and emphasizing the rounded contours mounting.

In addition to the harmony I wanted to the project, the factor that was important was the weight, as it was not something that was difficult to carry. So, I choose to make a ribbed box by adopting the MDF for the structural part, covered in wooden sheets, to give the equipment a natural look.

So I got a satisfactory, harmonic, beautiful and practical result and a very acceptable sonority, which made me quite proud of having designed and built it.

Step 1: Material

For the execution of this project, the following materials were used:

Laser cut MDF and acrylic parts;

Wooden sheets;

2 x homemade Crossovers;

1 x 50Wx50W Bluetooth amplifier;

2 x 50Wx8 Ohms JBL speakers;

2 x 30Wx6 Ohms tweeters;

1 x 12V x 5A switched power supply;

1 x Inox LED Button

Step 2: Electronics

The electronic part of the design consists of a 50Wx50W Bluetooth amplifier board and a set of homemade crossovers.

The amplifier board is generic, low cost, easily found on specialized sites in this type of equipment.

The crossovers were designed and built by me to meet the needs of the amplifier/speaker set.

The parameters of the crossovers depend on the characteristics of the speakers. In this project, 8 Ohm JBL woofers and 6 Ohm tweeters with a cutoff frequency of 8000 Hz were used. Given the ease of construction and low cost, Butterworth crossovers were chosen with 0.159 mH induction coils and polyester capacitors of 3.3uF.

Crossover.zip
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Step 3: Assembly

For the assembly, it was decided to use laser cut MDF plates, opting for a ribbed construction, giving rigidity and lightness to the project as a whole.

One detail worth mentioning was the assembly of the grid with the random circle patterns, a piece that brings personality to the project. To do this, I took a 3mm MDF sheet and covered it with a sheet of wood, which was taken to be laser cut. After the sanding and the application of the varnish, the result was above my expectations.

Drawing.dwg
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Step 4: Covering

After assembly, it was necessary to coat the entire box with sheets of wood. To do so, I used the technique of hot gluing, using an ironing iron to activate the glue applied to the two pieces to be glued. The process consists of joining the two pieces, dampening the wood sheet and applying the hot iron, causing the glue to soften with the formed water vapor, joining the two pieces permanently. After a few touches that were necessary, the process itself presents a very satisfactory result, allowing, even, the curvature of the sheet of wood.

After sanding the glued sheets, taking care to maintain a more rustic appearance, the varnish was applied, to reveal the beauty of the texture and color of the wood sheets.

Step 5: Final Assembly and Test

This was the most enjoyable stage of the project: to join wood and electronics in finalizing this project.

Step 6: Conclusion

This was one of the most incredible projects I
have ever done so far. The final result and the fun compensated the work and the time dedicated to the planning and assembly of this project, whose result can be verified in the photos published in this topic.