If you're talking about the standard Etherwave, you're in luck -- there ARE instructions ( unlike the Pro). Personally, I found the instructions in the manual almost impossible to understand, PLUS I've never owned a voltmeter or oscilloscope.
I posted a precise description of how to retune your Etherwave, and they're instructions that take into account things that the manual NEVER tells you about: such as the fact that you have to keep taking the cover on and off and on and off and on and off.
I'm unable to remember where I posted the instructions, but I'll look for them and re-post them here in this thread for you.
OKAY--- I found it. Forgive the length of this, but this requires a lot of detail. This is the post as originally written:
The most likely fix would involve re-tuning your pitch circuit – I’ve done this approximately three times to my theremin in the past eight years. It will give you back a wide pitch range again. In addition, you can also recalibrate ( perhaps not the correct term, but Kevin K. really knows his stuff and he can definitely help with precisely what to call things ) the pitch knob. In either case, you will be making very “fine tune” adjustments to the little “pots” on the tops of both the fixed and variable frequency oscillators. (How’m I doing, Kevin? ) It’s weird – I can DO it, I just have trouble SAYING it.
Both of these procedures involves opening up your theremin to make adjustments with a little plastic tool that’s like screwdriver. Exactly what to do depends upon what theremin you have. For a standard Etherwave, it can take about forty-five minutes. Increasing the pitch range is fairly straightforward. The trickiest part is getting the pitch knob to give you zero beat when positioned at about 12:00 rather than 5:00. It’s tricky because the lid has to be taken on and off repeatedly to make the adjustment.
If you’ve got a standard Etherwave, there are instructions in the manual, but they were written by Moogian Martians, so they’re a little difficult to understand.
As I mentioned before, you actually CAN get that setting straightened out, but to do it you will have to OPEN UP your theremin.
The primary reason to make this adjustment is that if you're currently at one extreme end of the pitch knob's position, over time you will be unable to get zero beat at all. If the knob is turned as far clockwise as it will go just to achieve silence, as the pitch "slippage" occurs -- and it will -- you'll be unable to adjust the knob. It may be okay now, and it may take months to fully slip, BUT it could easily happen INSTANTLY if you change location for a performance or something. Then you'd really be in a fix.
I've yet to have to make this adjustment to the Etherwave Pro, and the procedure will be different than the one described below.
BUT -- if you have a STANDARD ETHERWAVE, here's what to do.
If you have the standard Etherwave, you'll be adjusting the fixed pitch coil, L6. With the theremin turned off, you unplug the power supply, open the lid and place it aside. Plug the power supply back in. Now, turn the theremin on and turn the pitch knob (on the FRONT) to 12 noon. It's going to make a lot of noise.
Next, using a little plastic screwdriver, you turn the pot at the top of the L6 coil a little clockwise, or a little counterclockwise until you get zero beat. Make a note of the "hour" position of that little screw slot. ( five o'clock, three o'clock, etc.)
Now, place the theremin lid UPSIDE DOWN on the theremin. This is to simulate the lid being on. The position of zero beat CHANGES the second you put the lid on. So, to get things as accurate as you can without constantly having to take the lid on off on off on off, while plugging and unplugging the power supply, etc., you place it on top upside down. You'll notice that zero beat is no longer where it just was anymore. So, you need to compensate for what will hap