Re-purposed USB mini speaker amp

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Burned out my PC speaker salvaged amp on one channel.

:mad:Crossed wires preceded the event.

I had just finished by mini bookshelf speakers, so I badly need an amp. It occurred to me that the USB powered PC speakers might work off the USB phone chargers that come with every phone these days, so I rushed out and bought a set of these. I think it has a 8002 chip.

Similar to this one Cheap USB Speakers Teardown - YouTube

KazaiSpkr.jpg

Anyone tried this chip amp?

Removing the speaker front cover and the screws, I discovered that the amplifier was not inside the speaker but on the small volume control module.

After cutting the speaker wires and stripping the insulation, hooked it up and works very well, just needed a powerful enough phone the HTC one- details later.
 
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It's an 8002A

Some images of the board inside the volume control module, and close ups of the dual 8002A IC's, not the ones in the above You Tube video.

Listed as an type AB amplifier.
 

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Testing

These little guys are great! They'll run for weeks on 2 - "D" cells. Get the amp and trash the rest...
https://www.dollartree.com/E-Circuit-Battery-Powered-Mini-Speakers/p399637/index.pro


YouTube

Thanks for the link. Apparently these are not the same as the Dollar Tree mini speakers. I found a you tube test of the 8002A here:


Testing with some large Sony ES series speakers was very surprising, with good clarity and what seemed like 70DBA or so sound levels, the only misgiving is the lack of bass, which could be addressed with an EQ or some sort of a tone control. No loudness circuit here either.
 
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Testing with a CD player instead of the mobile player input as usual showed much promise. This is a really nice sounding amplifier, when given the proper line level inputs it works fine.

Working off the mobile phone at maximum volumes of both the amp and phone probably caused a lot of distortion, come to think of it.
 
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