Pitch issues

Posted: 9/10/2006 4:33:18 PM
Barl

From: New York, NY

Joined: 3/25/2005

I have had my etherwave for about two years now, but recently I've had problems. I cannot come close to the zero beat, that is, the point when turning the pitch knob where nothing is heard. In fact, I can only get a very high pitch, even when I turn the knob all the way to one side. Is there anyway to fix this? I cannot play the theremin as is, and it's killing me as a result.

Thanks in advance.
Posted: 9/10/2006 8:54:11 PM
Jeff S

From: N.E. Ohio

Joined: 2/14/2005

No problem! All the instructions you need are in the Etherwave Hot-Rodding Manual. If you don't have one, you can download the PDF file for free from the Moog Music website. Here's the link:

Etherwave Hot-Rodding Manual (http://www.moogmusic.com/manuals/HotRodEtherwav.pdf#search=%22%2Betherwave%20%2B%22hot-rodding%22%22)

Good luck!
Posted: 9/10/2006 9:34:10 PM
Barl

From: New York, NY

Joined: 3/25/2005

Thanks a lot, I'm looking at the pdf now.
Posted: 9/11/2006 8:39:33 AM
DiggyDog

From: Jax, FL

Joined: 2/14/2005

Before you start fixing the problem, is there any chance it is just something interfering with the field?

My guess is that you have already tried setting it up in a wife open space to make sure that is not the problem.

If not, try it.

Good luck.
Posted: 9/12/2006 3:06:06 PM
schielenkrahe

From: Morrisville, PA

Joined: 10/19/2005

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
Posted: 9/17/2006 2:18:11 PM
Barl

From: New York, NY

Joined: 3/25/2005

schielenkrahe, thanks a lot. My only issue is, I don't know how to turn L6, I don't own any tiny plastic hex-wrenches.
Posted: 9/17/2006 6:43:59 PM
DiggyDog

From: Jax, FL

Joined: 2/14/2005

Believe it or not those instructions seem very clear.

When it is time for me to recalibrate mine I will definitely refer back to this post.

I wonder if it would be easy (or even possible) to modify the instrument so that the adjustment screws could be accessed with the cover on. Do they have to be in close proximity to the pots or could they be moved to a different position at the back of the instrument?

Posted: 9/17/2006 6:58:48 PM
vonbuck

From: new haven ct.

Joined: 7/8/2005

the nice thing about making the etherwave left handed, holes in the bottom to access those adjustments without having to take things apart


Andy
Posted: 9/19/2006 10:36:23 AM
schielenkrahe

From: Morrisville, PA

Joined: 10/19/2005

Here's a little more to clarify.

The little plastic screwdrivers are very common, purchased at Radio Shack. It's not the HEX end that you use, just the standard screwdriver. It fits right down into the hole on the pots, fits directly into the screw slots -- then you make very small adjustments.

The pots are located INSIDE the circuit, accessed through the hole, so I'm unaware as to how one might re-position or re-configure them to face another direction.

However, I suppose it VERY possible to drill access holes directly through the top of the Etherwave's cover, enabling one to adjust every pitch and volume circuit with the cover remaining on at all times. Seems like a good idea, in fact! And if, for some unknown Sci-Fi type of reason it adversely impacted the theremin's playability (although I'm unable to see how it would) you could always plug the holes back up.

SO!!... who's going to be the first kid on the block to drill the holes?
Posted: 10/6/2006 7:54:15 PM
Barl

From: New York, NY

Joined: 3/25/2005

Hopefully someone is still looking at this thread. I have screw drivers that fit into the oscillator, but it looks to me that the hexagonal holes in it go all the way to the base of the circuit board (i.e. I don't see any screw slots.) Also, I went to Radio Shack and asked about plastic electronics screwdrivers, and they looked at me like I was crazy. What am I missing with these things?

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