Howdy...The Evolver is a pretty rad little synth. It's got a mixture of digital and analog components and a sequencer inside. It's also got stereo sound, built-in delay unit (with some funky parameters!) and built-in distortions (two very different types).
It normally comes in a small, black case which is quite suitable, however, I wanted to enjoy mine in a certain way: I wanted portability, freedom (two huge themes with me) and a headphone jack.
At first I searched Radio Shack, couldn't find, and then finally built, an obnoxious dual 1/4" to 1/8" stereo headphone adaptor. It wasn't very robust though. Also, there wasn't enough space inside the original case to fit any batteries in.
So, finally, on Christmas break, when I had about 3 days to myself, I did this project.
Also, even though it says 400mA, it uses a little bit less. At first, I was using 8 cheap Ni-Cad Batteries with 4 expensive NimH ones. But that was obnoxious. Because the two types have different capacities, one set of batt's would die, while the first one was still good. Then, I'd recharge the first set, and the second one would quickly go dead. It was very disturbing and I'm already on the edge, so I splurged for a full set of identical NimH batt's.
They last quite a while. They're rated for 1800mAH, so they should last around 4 hours. Real life, especially as seen through the eyes of Radio Shack, is never ideal, so don't expect them to last forever. I will say, though, I am given to long sessions with this thing, and it rarely runs out in the middle of them.
After I built the case, I put velcro on the inside to
steady the two battery holders. You don't really want
them flopping around inside your synth.
Getting the positioning of all the holes and stuff was a pain. Basically, I removed the top of the original case, then put a piece of white paper under it, and traced the cut holes onto the paper. Then, I held the paper up to a light (the sun worked well on my porch) and traced through the LED holes. Note: you do NOT need to cut through the LED Display- It lies very flat on the board.
After I had all the holes, I drilled them. In most cases, I didn't have the properly-sized drill bits and I spent waay too much time refining the holes to be slightly larger. That is to say, I reamed a number of holes that day, to the point where my body was quite tired. So, try to get the right-sized drill bits and you'll save yourself some agony. That's not dogma, just good advice you should consider.
Eventually, I had this cool Lexan front panel. BTW, I recommend it not only because it looks cool, but it's much easier to work with than metal, and doesn't get deformed like metal. Once I determined that it fit well, I was psyched, even though I knew there was a lot more work to be done.
BTW, at first I thought it would be cool to copy it onto a transparency, so you could still see the electronics behind it, but my first attempt didn't work at well- you couldn't see the words against the busy background. Maybe someone could design a more visible parameter sheet?
At first, I was going to make one huge, wrap-around piece of metal but it would have been like 40 inches long. That's obnoxious to work with, and besides my sheet metal stock wasn't that big in any dimension. Two, 20 - inch panels works out much better. BTW, do some good measuring. I didn't do good measuring, and I have 1/2-inch gaps on the front and back of my case. Not a big deal for me, because I don't care about the looks too much, just the func., but you might.
Each of my panels bends in three, and has a 1/4" flap at the top and bottom for mounting the lexan face and the simple sheet metal bottom.
To minimize waste and time etc, I first made stiff cardboard models of the panels. I used the remains of a poster I used to try to get Jill Stein elected. Figured it was an excellent example of Reuse. Then, once I got it trimmed down to the right shape/size, I traced it onto sheet metal and trimmed.
Man, does that give your forearms a workout. They were hurting like crazy for days after this. Then, you fold. If you're really clever, you'll be able to drill the holes for mounting the sides to the top before you fold! I wasn't.
Additionally, you want holes for the power switch and the headphone jack. Check out my photos to see where I laid these out.
