Theremax Optimal Pitch and Volume Oscillator Frequencies

Posted: 7/20/2012 6:12:28 AM
gnsmith116

From: Northern Virginia, USA

Joined: 5/10/2012

Christopher,

In case you have any problems looking at the pdf files on Element 14 I have directly inserted a few images below:

Closeup of board showing some mods and isolation walls

 

This is the way I built the LEV antenna to screw on the compression fitting as the standard tubing antenna.  There are construction details in the document.

LEV Antenna Mounting

 

This is an overall view of the Thermax

Theremax Build

 

 

 

Posted: 7/20/2012 11:36:17 AM
FredM

From: Eastleigh, Hampshire, U.K. ................................... Fred Mundell. ................................... Electronics Engineer. (Primarily Analogue) .. CV Synths 1974-1980 .. Theremin developer 2007 to present .. soon to be Developing / Trading as WaveCrafter.com . ...................................

Joined: 12/7/2007

Thanks for uploading that stuff to Element-14, Greg.

I am inserting direct links below:

theremax base build characteristics.pdf

theremax build pre mod.pdf

theremax digital noise mitigation and lev antenna build details.pdf

Really great to have some more data on this theremin, thanks! Also interesting to see your construction of the Lev antenna.

Fred.

Posted: 7/20/2012 12:52:30 PM
gnsmith116

From: Northern Virginia, USA

Joined: 5/10/2012

gnsmith said: "it's a Theremax - of course it is running through a grounded shield!  Maybe that should be changed.  I'll get you pictures later tonight."

Christopher said: "I never knew of this coax as I never owned a Theremax. Could this be why many may have failed to experience the phenomenon of linearity and were too kind to report back to me..."

Sorry about not responding immediately to this post, I was fixated on getting the data that I promised out.  I am going to collect linearity data on my two current antenna options from 450kHz to 1MHz to try to get some insight into what the parasitics in my own particular build are.  I'll plot those and send them out.  There is a difference in response between my LEV build and the 18" tubing it was just at 820KHz they are the same.

Also, when I built my LEV antenna I didn't have the page open, and I just remembered to stretch the spring 1/2 inch.  Now that I know that needs to be calibrated I think I will add a vertical plastic adjustment screw at the top so I can tweak the stretch.

BTW, the pictured build looks good.

Greg

 

Posted: 7/20/2012 1:04:25 PM
RS Theremin

From: 60 mi. N of San Diego CA

Joined: 2/15/2005

"Lev Sergeyevich just loves the look of a spring early in the morning, he will say the sun is shinning!"

Greg those are great photos with clarity. If you are in it to win it then the coax has to go. Use a direct wire kept away from the grounded shields and IF can. The connecting wire is part of the antenna or maybe part of the circuit? 

The way the Theremax has the antenna setup now it is like placing your volume or left hand near the base of the pitch antenna and expect it to play with linearity using your right hand.

Fred what would be the statistical odds that I could pull out of thin air a theremin combination of antenna design and the operating frequency, then have it work as I have always said it does from my first original theremin design with no experience 10 years ago.

Did I get lucky, maybe inspiration, magic, channeled the thoughts, shiitake mushrooms or some other method that science does not recognize the possibilities.

Greg it is time, I am counting on your success, then I will simply float away.

Christopher

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