Small Pitch Region - Moog Etherwave Plus (kit)

Posted: 1/22/2014 10:36:35 AM
fryzers

From: Rye, England, UK

Joined: 1/13/2014

Ok, I have 2 issues/questions since building my MOOG Theremin (Plus). 

The distance between zero beat region and the pitch antenna seemed a bit small (about the length of an A4 sheet of paper. It’s since got smaller when I started it yesterday. I was expected the sound to start a couple of feet away. 

Also is it normal that when I move further away from a Theremin past the zero beat region the pitch starts rising again? This has since happened.

I think I need a tune or do I have a broken Theremin?
I found this online… do you recommend? Any tips? http://www.wolinlabs.com/blog/etherwave.tune.html

Thank you in advance….

Posted: 1/22/2014 11:16:56 AM
Thierry

From: Colmar, France

Joined: 12/31/2007

The distance between zero beat region and the pitch antenna seemed a bit small (about the length of an A4 sheet of paper. It’s since got smaller when I started it yesterday. I was expected the sound to start a couple of feet away. 

Can't it be compensated with the pitch knob? Turning it counterclockwise should bring the zero beat region more far away from the pitch antenna

Also is it normal that when I move further away from a Theremin past the zero beat region the pitch starts rising again? This has since happened.

Yes, that is absolutely normal.

 

I think I need a tune or do I have a broken Theremin? 

 

As long as you can adjust the pitch field for convenient size and tone spacing with the pitch knob, there is no need to fiddle with the internal adjustments, the risk of making things worse is too high!

 

I found this online… do you recommend? Any tips? http://www.wolinlabs.com/blog/etherwave.tune.html

 

Noooo! It's ways too complicated and as I wrote above, there is a risk of messing things still more up. If the pitch knob does not longer allow to bring the zero beat zone to about 60cm from the antenna when positioned somewhere between 9 and 3 o'clock, open the lid, take the red plastic special tuning tool which came with the theremin, locate the variable inductor L6 and adjust it as follows: If the pitch knob is too much clockwise, turn L6 an eighth of a turn counterclockwise. If the pitch knob is too much counterclockwise, turn L6 an eighth of a turn clockwise. Don't touch the other inductors! Close the lid, let the theremin warm up for at least 5 minutes and check if the zero beat zone can now be correctly adjusted with the pitch knob. If needed, repeat the above procedure.

Posted: 1/22/2014 11:52:44 AM
fryzers

From: Rye, England, UK

Joined: 1/13/2014

Ok, I'll try the latter as currently the Pitch knob is not doing as you say it should.

Thank you

Posted: 1/22/2014 11:54:22 AM
fryzers

From: Rye, England, UK

Joined: 1/13/2014

I'm assuming it's labelled L6?

Posted: 1/22/2014 12:13:41 PM
Thierry

From: Colmar, France

Joined: 12/31/2007

Yes, it's labeled L6. There are 3 variable inductors on the main circuit board which are labelled from left to right: L11, L6, and L5. Thus it is the one in the middle.

 

P.S.: It's important to check the pitch field with the lid closed since the 9 screws inside the cover part of the housing are part of the capacitive environment. You'll find the pitch field ways too compressed when trying to play an Etherwave without its cover.

Posted: 1/23/2014 6:49:48 AM
fryzers

From: Rye, England, UK

Joined: 1/13/2014

Excellent. It worked. Thank you for your help.

Posted: 1/23/2014 8:11:52 AM
Thierry

From: Colmar, France

Joined: 12/31/2007

You're welcome! I'm here for that!

Posted: 1/23/2014 12:25:32 PM
fryzers

From: Rye, England, UK

Joined: 1/13/2014

Pitch range is now too huge after it warmed up, so I need to make some minor adjustments. At least I know that sorts the issue out now.

Posted: 2/16/2018 6:05:34 PM
Emmanuelle

From: Berlin, Germany

Joined: 10/12/2017

"If the pitch knob does not longer allow to bring the zero beat zone to about 60cm from the antenna when positioned somewhere between 9 and 3 o'clock, open the lid, take the red plastic special tuning tool which came with the theremin, locate the variable inductor L6 and adjust it as follows: If the pitch knob is too much clockwise, turn L6 an eighth of a turn counterclockwise. If the pitch knob is too much counterclockwise, turn L6 an eighth of a turn clockwise."

I don't know why, but my theremin was extremely out of tune today. The field was too small, even with the pitch knob turned completely to the left. What could cause such a phenomenon, in such a rapid and extreme way ? The room/configuration I play in hasn't changed.

I was very anxious to open the case of my theremin, but I finally did it, followed Thierry's instructions and ... it worked !

Thank you so much !! Feeling happy and proud tonight ;)

Cheers !

You must be logged in to post a reply. Please log in or register for a new account.