Battery powered amps are inexpensive and easy to make, so when I made one, I decided to put my own (sorry) "spin" on it. I built it in a globe so I could manually spin the speaker, creating a phasing, "Leslie" effect. You can watch this video which shows how I did it or read the following Instructable. You can also see a performance video of the speaker in action here:
Thanks and be good,
Step 1: Parts and Such
I bought the amp electronics on Ebay for about $25. I used a 3.5" speaker out of an old radio and a Soviet-era globe. First I needed to remove the speaker and get the globe off it's little base, so I could build a larger, wood base to house the electronics.
The pin that the globe spins on was solid, so I bought a small, hollow steel split ferrule I was able to hammer in the hole, allowing wires to snake up through the post and into the speaker.
Yes, the wires do twist a bit as I spin, but inside the globe and ferrule. I left the wires extra long to allow for this and spin the globe in opposite directions each time I turn it to unwind the previous wind.
Step 2: Mount the Speaker
I drilled a hole in the globe oversized for the speaker so I could mount the speaker in to the waste part of the cut, then create a mounting system to put the speaker back in. I used some seatbelt material and epoxy but it is kind of ugly. I would come up with something better if I did this again.
YES I KNOW it looks like the Death Star. But I chose to keep it as a globe. Life over death, y'know?
Step 3: Build a Box
I used reclaimed oak and mahogany to build a slightly complicated tapered box. the math was nutty and it required some trial and error to get it to fit right. You can make a regular box instead. I drilled holes for the knobs and jack.
Step 4: Plug-n-play
I mounted the pre-wired electronics in the box, connected the speaker and that's it! Watch the video(s) to see and hear it in action. If I were to try to one up this again, I would use some small electric motor to spin the globe controlled by a foot-activated rheostat :)