Back when I decided that a theremin was a necessary component to my existence second only to the general category including pizza, coffee, sunglasses, French hard cider and loud music, I researched around for one that my meager budget could afford.  The offerings out there ranged from so-called optical theremins (not really a theremin, being based on light fluctuations, not body capacitance) to various cheap theremins with only one antenna (purists scoff at these, since the single antenna controls only pitch, and there is no volume control) to kits to big fancy nice-looking expensive ones.

Since I am a cheapskate I did a lot of research and finally chose the single-antenna theremin made by Theremaniacs.  This review is for the (no soldering) kit, which is even more inexpensive because though it comes ready to use, you must mount it into some sort of case yourself. 

But this review also could cover the already-mounted Theremanics theremin also.

What you get with the kit is a small circuit board connected with some wires going to an output jack and some other wires going to a knob, wires to the 9volt battery supply connector, an another wire meant to be connected to an antenna.  The antenna is included as is a weird little purple screwdriver used to adjust the coils on the thing and a battery holder.

In theory you could test your theremin without a box by putting it onto a table away from any metal objects.  To get the kit going, you connect it to the battery, connect the wire to the antenna via a screw on the antenna, and then connect the output to your amplifier.  It should make a sound right away.  Then you take the purple screwdriver and adjust the sensitivity coils so that it doesn't make sound when you are not near it.  Then after that you can adjust the coil until you reach a good level of sensitivity (about 2 feet).  The maker advertises a 3-foot range of sensitivity but it's a little hard to get it to that level (it will at some point of sensitivity is just stay on by itself).


Mounting it in a case is easy. The only thing to remember is that the case cannot be metal, it has to be plastic or wood or rubber or clay or goo or whatever. Essentially you could do the mounting in 1 minute with an empty shoebox if you wanted, by punching a couple holes in it. 

Okay I will end with a pros and cons list.

pros: 

1. inexpensive
2. reliable.  After 6 years only minor fluctuations in its performance
3. service help: Chuck the guy who sells them answered my emails when I had questions
   
4. easy to make noise with
   
5. battery lasts forever, like more than a year from a single 9 volt battery even with heavy use.
   
6. can easily be installed in a plastic skull, a cigar box or anything not made of metal.
7. guitar jack output connects via cable to your guitar or bass amplifier, and the volume will set off smoke alarms
8. analog sound really does sound better than digital
9. single antenna is simpler to use and to practice melodies without worrying about volume control
   

cons: 

1. relatively hard to play music in tune on it due to its variable sensitivity
   
2. no built-speaker so you can't listen to it as is, you must connect it to a speaker or amp
3. no volume knob at all, volume control at the speaker/amp
   
4. single antenna means you can't practice adjusting the volume with your other hand as you would with a classic theremin