41Hz Audio's AMP4

I've been looking for the ideal bicycle audio amplifier for a long time. The key requirements are very high efficiency at reasonably high power rating but with relatively low voltage supply requirements. 41Hz Audio's AMP4 project seems to fit, so I decided to try it out.

The kit is nicely put together and assembly was surprisingly easy. I have lots of threw hole experience, but I haven't done much surface mount, so when it came time to solder the PowerSO36 package, with its 0.65mm (0.023") pitch pins, I was a little worried. It turned out to be no problem, even with the metal slug effecting heating of the pins.

AMP4_PowerSO36.jpg

More generally, the very sensible PCB layout definitely helped make the assembly go smoothly - no via's too close to pins, and lots of room to place parts and access leads. There is a minor layout error on the rev 1.02 boards (41Hz Audio forum discussion), a couple of pins on the voltage supervisor chip are reversed. I don't need that function, but fixing the problem isn't hard, just solder the part upside down.

(warning, the full size images are very large)

AMP4_top.jpg	AMP4_bottom.jpg

Now all I need is a mini sonotube subwoofer! I'll be able to produce a pretty impressive thump, while keeping weight low.