My etherwave theremin had been working fine on the microphone stand for months now when I move away 3 feet or more the pitch goes on auto pilot. When I take it off the microphone stand it and set it on a table it works fine. Any thoughts on how to solve this. Also I use a Behringer Digital Delay and a 15 watt Marshall guitar amp both seem to work fine with the theremin.
What do you mean by “autopilot”?
I seem to be having a similar problem. I just got a Moog Etherwave Standard theremin about two days ago; it was working fine on a table, but when I decided to put it on a mic stand, it began to behave strangely. When I’m not close to it, it emits a high pitch. When I begin to move my hand toward the pitch antenna, the pitch begins to lower. At about seven inches away, it hits its lowest point; as I move closer than seven inches, the pitch begins to increase again. This only happens when the theremin is on a mic stand; on a table it works just fine. Any suggestions?
Shadolith,
Adjust your pith knob.
The antennae emit a figure-eight pattern. The theremin is supposed to be set so that standing at arms length, you get zero beat at your shoulder, so the entire range of the theremin is an arms length. This is the the traditional setting. You move closer to the antenna, you increase pitch. Farther away, you decrease it.
The Volume is such that as you approach the antenna, the volume fades. These settings are indicitave of there being a circular pattern emanating from your antennae. Theres nothing wrong here, but the settings aren’t at their maximum.
So lets set the setting at maximum and analyze the field. Its a huge figure eight. So standing in zero beat, this is how the instrument will respond: As you approach the pitch antenna you will activate the highest notes of the Theremin and descend until you reach a point where you are at the center of the figure eight in a second zero beat (if I remember correctly). Then, as you continue to move closer to the antenna it will reverse itself, you will activate the bass notes and ascend until you touch the pitch antenna.
I don’t have my theremin here to tell you what settings are considered normal, but it’s the only instrument Ive seen where the pitch and volume knobs don’t actually affect pitch and volume lol. Try the 12:00 or 1:00 position for the pitch and see if that helps.
i’m very surprised to read anybody can get a theremin working on a table ~ I haven’t tried that with mine but saw the warnings against it and in fact, the first time I saw one that’s how the fellow had it set up and he couldn’t get a peep out of it. 
I wonder does anybody know if the height of the room will have any effect on tuning and getting a good full range pitch response?