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“Mini” is the main feature of this speaker set. To achieve stereo sound, two-channel speakers are required, but to maintain the “mini” aspect, the distance between the two-channel speakers is limited. When two speakers are too close, there is essentially no stereo effect, making it meaningless to design two channels. Therefore, to reduce the size, the “mini desktop speaker” adopts a mono design, which can meet the requirements of most occasions.
The motivation for designing it comes from a batch of discarded circuit boards provided by the school, which appear to be from some radios. Among them, there is one very prominent chip.
It took quite a bit of effort to take it apart and gather its information.
Based on the LA4446 chip, I found a related circuit diagram.
The circuit is quite simple, so I drew it up using DXP. The PCB uses a single-sided layout, with dimensions of 10cm x 5cm. The audio input traces should be kept as short as possible, and the ground area should be appropriately increased to help the IC dissipate heat through the copper foil.
I used heat transfer printing, and the effect was mediocre on large areas, so I touched it up with a marker.
All the components used in this production are basically old disassembled parts, which better reflect the significance of the production.
The effect is still quite ideal. As for adjusting the volume, it is done at the input end (mobile phone, computer). You can also connect a potentiometer and capacitor at the input to adjust the volume!
The power supply was also selected; I chose a 12V adapter to ensure the “mini” aspect.
When working, the IC gets warm, but it won’t get hot enough to burn your hand. If it gets too hot, it could be due to a short circuit in the output. This production has a high success rate and can be completed in one go. I also added attachments for your learning. Although the mini desktop speaker is very small, the effect is still quite satisfactory. Whether during leisure time or at work, the wonderful sound can always give people a comfortable feeling. Making a mini desktop speaker yourself and placing it on your desk allows you to quietly appreciate the unique experience it brings.
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