Moving zero-beat?

I've looked at the Moog Etherwave FAQ and don't feel like I have an answer yet. I've got a used Etherwave Plus [edit, I said "pro" originally, apologies]. When I start playing after turning my theremin on, the "pitch" dial position doesn't seem to relate to anything anymore (the zero beat is something way out of arm's reach). Once I adjust the dial and my own position, even over the course of a little 20-minute practice session the zero beat moves so much that I end up adjusting the dial by about 30 degrees.

The Moog FAQ says I should expect the zero beat to move, and there's going to be a little bit of play based on posture and probably how well I've been sticking to my diet, but this seems a little bit much, a noticable shift in the zero beat even during a single attempt at a song. Should I be taking my Etherwave to the local synth repair shop? Advice appreciated! 

The local Synth shop won't help.

If you really own an Etherwave Pro which is not longer in production since 2005 or so (do not confound this with the common Etherwave Plus), even Moog Music Inc will most probably tell you that they do not longer have the people and/or the parts to fix this model.

There is a guy in Europe who knows how to fix these beasts. You may contact him by email: service(at)theremin(dot)tf.

Oh, no, you're correct! I have a plus, not a pro, my apologies. 

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The local Synth shop won't help.

If you really own an Etherwave Pro which is not longer in production since 2005 or so (do not confound this with the common Etherwave Plus), even Moog Music Inc will most probably tell you that they do not longer have the people and/or the parts to fix this model.

There is a guy in Europe who knows how to fix these beasts. You may contact him by email: service(at)theremin(dot)tf.

Ok... The Etherwave Plus has (depending on ambient temperature and component tolerances) a warm-up time of up to 20 minutes. The biggest changes occur during the first 5 minutes. Thus switch it on, mute it, wait 5 minutes (have a coffee or a cigarette) and then tune it so that if you are standing at arm length from the pitch antenna, the zero beat is very close to you and pitch starts as soon as you move your right hand away from your right shoulder towards the pitch antenna. Now it may be that you will still have to fine-tune that during the next  15 minutes. As long as the pitch knob will then be between 10 o'clock and 2 o'clock (12 o'clock being the center position), everything is fine. The pitch knob is there to compensate the temperature factor and parasitic capacitance of the theremin's environment, so you should never expect it to be exactly in center position.

Hello Khaladog,

I am happy you do not have a Pro. Here is a collection of EWS knowledge I keep. If I was to invest in a Pro I would purchase it directly from Thierry.

Always a Solid Buy, the EWS or +

Christopher

Thanks, Thierry, that's good information, I hadn't thought about a warm-up time. Much appreciated. I got distracted by a phone call and left it humming to itself, the slowly increasing pitch was pretty evident.

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Ok... The Etherwave Plus has (depending on ambient temperature and component tolerances) a warm-up time of up to 20 minutes. The biggest changes occur during the first 5 minutes....