Some small audio amplifiers

This is my version of “3 – 5 Watt Class-A Audio Amplifier” (

(If the link above doesn’t work, use the Internet Archive, e.g.

Wikipedia says enough about “Class A” and you can’t buy one nowadays – good thing they are easy enough to build, if you want to try one. 😉

CIMG0670 CIMG0671

At this moment I don’t remember the exact type of bipolar power transistors I used, but they were on clearance sale anyway.


They really get hot – and yes, hottest if silent. (So in the meantime I zip tied fans on top of the heatsinks, switched on by a bimetal switch I had lying around.)

This is the case. Ferrero Rocher. Meant to be preliminary, but this also holds good for “nothing is more definitive than the temporary“.

CIMG0674 CIMG0675

Oh, it’s illuminated a bit. ^^


And here is another one. This was soldered together to drive some PC speakers at work. Meanwhile they gave me sufficient equipment to hear my Outlook reminders, so this one is retired.

That National Semiconductor LM386N-3 is so polular it’s on Wikipedia: !

Schematic? Just look at the “Typical Application” in the datasheet.

DSCN6533 DSCN6534 DSCN6536 DSCN6537 DSCN6539 DSCN6541 DSCN6544

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