Posted By azog on May 20, 2009
As I try to fill an empty space in my life, wishing for one particular female to respond either negatively or positively to my hints (although no response is basically negative, isn’t it?), I move on to a new project.
I’ve been wanting to play with theremins for a bit now. There are many options, from “toys” to DIY plans. I didn’t want to go down either of those routes, so I ended up going with a a PAiA Theremax Theremin kit, including the case.
Another option was a Moog Etherwave, which is both assembled or a kit. But it is more expensive than the the PAiA. I figure if I decided I really really like playing a Theremin, maybe I’ll eventually get an assembled Etherwave.
There are lots of images and a video, so the rest of the post is after the “more”
Opening the box, I was unpleasantly surprised by their choice of packing materials.
Styro peanuts? Seriously? Irritation aside from the type of packing material, I began to set out my workplace. Like any overeager builder, I carefully tossed the instructions aside, scoffing at the very idea.
I like the considerate addition of a resistor cheat sheet. This is not all the parts. I left the case, case assembly, and other sundries parts aside. Looking at this particular heap of parts, I began to reconsider my scoff of the instructions manual. After a few hours…
I did run into one problem with a missing, or mismatched, resistor. The manual said to call them in case of missing parts, but I’m not gonna bother them over a lousy one-cent resistor. It would have cost them more to process and mail this than worth. Besides, I was anxious to move on. So I substituted by matching two fairly equivalent resistors in series. No biggie.
Once the main board was finished, it was time to move on to the front panel. This was surprising pretty involved.
Now to begin putting it all together, starting with the case.
A couple of snags here. The supplied screws stripped just too easy. I used a proper bit, and set my screwdriver at the lowest torque, so I won’t blame myself for this one, pfft. I had to grab a few brass wood screws as replacements. Also the mounting holes on the bottom plate, which attach (and ground) the board and panel were oh so slightly off. But finally I ended up with…
Now it was time for the first test. I plugged my amp in, supplied the theremin with power, and the power LED glowed, which was good. No smoke escaped, either, which was doubly-good. But I wasn’t getting any response. No tones, the knobs didn’t do anything.
I poked around for a bit, and just broke down and removed the mainboard to verify my solder work. Ultimately I ended up just fluxing and re-flowing most/all of the solder joints, Just In Case. And when I reassembled it, I was getting some response.
The final part is to tune the instrument, which seems to be pretty complex. You have to tune at least two coils, one for tone and one for volume. I got it to the point of “it works, it needs to be tweaked”, and finally just decided to call it quits for now, and then put the top cover on the case.
Couple of final things…
I’m left-handed, so I reversed the antennae as is usual. If you look at other theremins, the volume is controlled with the left hand, and the tone is controlled with the right. So, since I wanted to control the tone with my left, it was just a matter of doing it wrong, err, backwards.
I don’t have a non-conductive tool to tune the coils, so every time I get close, I’m inadvertently modifying the behavior, so that is making it hard to tune the coils.
When I checked my work on the mainboard, I did not check my work on the front panel, and for some reason, that is bothering me. The front panel build was kind of involved, wires go here, wires go there, wires go everywhere.
Ultimately, I think I would put this on the “advanced builder” scale. Not saying that I’m advanced or anything, but it does get pretty involved. There are many different types of resistors, and after a couple of hours squinting at colors, it’s just real easy to transpose them. And as I just mentioned, the front panel was just as involved. I spent two days on the build, including initial troubleshooting and re-soldering, which is probably about 8 hours. I spent a couple more hours playing with the tuning, but I’ll revisit that shortly.
In the meantime, I took a brief (and bad) video of the first post-tuning.