Description:
The LM3886 is one of the most popular gainclone chip amps. It features high power (68WRMS, 135W peak) into a 4-ohm speaker, mute, and simple circuitry, making it an excellent choice for the beginner and professional alike.
I would like to thank bigparsnip from the DIYAudio Forums for designing this PCB and schematic and allowing it to be posted on electroNET.
Schematic:
PARTS LIST:
| Part # | Description |
| R1 | Varies depending on Power Supply Voltage - See datasheet |
| R2 | 50K - 1/4W 1% tolerance |
| R3 | 1K - 1/4W 5% tolerance |
| R4 | 1K - 1/4W 5% tolerance |
| C1 | 100UF - Polarized electrolytic |
| C2 | 22uf - Ceramic or similar |
| C3 | 0.1uf - Polypropylene or similar |
| C4 | 0.1uf - Polypropylene or similar |
PCB:
Usage:
Build the amplifier following the schematic and PCB. As always, when testing it, test with a cheap speaker that damage to will not cost much to replace.
If your source is consistantly connected (ex. a pre-amp always connected to the amplifier), you can skip C2 by soldering a jumper in place of it on the PCB. If possible I would highly reccomend doing this to decrease signal path and increase audio quality. However, if your source may ever get disconnected (such as a CD player), it is reccomended that you include C2. If you do not, disconnecting the source will send a large DC current into the speaker and will very likely damage it.
Photos of my amp:
Finished PCB
Amplifier mounted on aluminum plate (this amp is used as a subwoofer amplifier).
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Downloads: Links:
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