I built a small battery-powered amplifier today.
Not too long ago, I bought a small, inexpensive amplifier kit from tindie.
I partially wanted to test the tindie waters and support the cause (since it's such a great idea), but I also figured I could kill two additional birds with this buy-build-a-kit-stone:
- Get a small battery-powered (read: safe) and portable amplifier going to support circuit bending.
- Teach a 5-year old how to solder.
We started in the morning and had about 2/3 of the soldering done within an hour or two. The child's amazing pencil grip guided the tip steadily to its destination, and within 3 or 7 attempts he was inserting parts, soldering (disclaimer: one-handed, I worked the actual solder...gotta build up to these things), and snipping off the legs with dykes. He performed about half the solder joints on the small circuit board..which means SUCCESS! :)
I later went to the neighborhood Goodwill and found a random but nice fake-wood-its-really-cardboard box, then went to a neighborhood store to buy the hinges.
As always, the mechanical/physical part of the work always always ALWAYS takes 5x longer than the other stuff.
The neighborhood store didn't have a small enough clasp/latch, so I'm still on the lookout for one. Also, I mounted the external output/hacks/headphone jack...but it's not yet connected to anything. And lastly, I haven't put knob covers on yet.
When all was done, the build turned out pretty clean: 
The amp sounds good, even though I've only yet plugged a microphone and cellphone into it. It's designed to be an instrument (guitar) amp, and you can hear that from some of the tweakable distortion that's easily created. For the cheap driver's size, the low end is reasonable. In its current 6V configuration, it's not terribly loud and I do wish it was capable of pushing a few more watts....which I may end up hacking in eventually (along with the headphones/lineout capability).
All in all, an enjoyable build for a lazy labor day.