THEREMIN - Simple Volume Control Schematic?

Posted: 3/13/2019 6:27:18 PM

Joined: 3/13/2019

I wanted to know if there's anyone successful in designing a sioles Volume Control circuit for THEREMIN? As there are lots of Pitch only circuits available, but no Volume Control. I also tried to design it using F to V & then VCA,etc, but Couldn't succeed. Does the Strange Apparatus schematic for Volume Control works?
Any suggestions for Volume Control or any sinpsi schematic possible for beginners to try their hands on?

Posted: 3/13/2019 7:21:18 PM

From: Northern NJ, USA

Joined: 2/17/2012

The VCA is half the battle, this one works really well:

Download my LTSpice file to see the schematic and simulate it (LTSpice is a free Spice circuit simulator).  Two JFETs and an opamp.

You would need to feed it a voltage from a resonant tank circuit.

Posted: 3/15/2019 6:05:33 AM

Joined: 11/25/2017

If someone posts a request and I give a solid theremin answer and they do not respond within 24 hours I will delete it as I am against filling the Google data base with ego driven nonsense.There are many ways to do any project and I must leave room for those that have never demonstrated anything that works properly.Oh shit… now the pitts bull will be after me or stock me. You ever notice how small their craniums are, and probably that other thing they lick.pitbull will come around, he knows these moments are rare and who I am.Christopher

uhh ... Christoper, I've often problems understanding what you mean in your posts. I'm not a native speaker - sorry. But I think it should be an attac against pitts8rh - So please stop it. And please stop posting copyright protected pictures or logos. Be more creative and create your own artwork.

Posted: 3/15/2019 11:29:32 AM

From: 60 Miles North of San Diego, CA

Joined: 10/1/2014

Edit:   gerd there is a piece of Art on my website you do not think honors the artist who made it. I will give you a special power being you are a princess. I think I know what it is and if you tell me you want it removed I will remove the entire website until April 1, just for fun. We can tell stories of what happen to the website. I have nothing to sell and a little vacation would be nice now. But I still get to pick on the pitbull.  Look at him down there, he is just sooo cute. These days we get one or two new posts a week at TW, we must keep it entertaining and not so much scary ego driven nonsense.


Often a "sense of humor" does not translate well, the word "stock" should have been stalk, would you correct that for me.

Are you suggesting man bites dog and not the way I tried to express it?

Thank you

Disclaimer: I did not draw this picture.


Posted: 3/15/2019 3:07:29 PM

From: Berlin Germany

Joined: 4/27/2016

A good way is a frequency oscillator that is weakly coupled to a resonant filter whose capacitance is meanly the antenna loop. Either the oscillator or the filter must by adjustable to guarantee a resonance voltage of some volts. Due to the hand capacitance the filter will be dismatched and the r.f. voltage breaks more and more down. The filter is followed by a high ohmic buffer and a rectifier to get dc voltage. Then follows a vca. 

Two examples that are tested I gave in this forum to discuss.

Both are functionable. The first is shown in my Fruity Theremin video and the second in Theremin KRAFTWERK video

Posted: 3/15/2019 5:54:43 PM

From: 60 Miles North of San Diego, CA

Joined: 10/1/2014

Gerd is the daughter of a giant and the wife of Frey.

Forgive me as I now realize your sensitivity is because you are a lady.

My mentor said: “ask her if she sings when she plays the theremin?”

No no that can’t be you...    you know her though, does she live nearby?

I am just a giant oaf


More stolen art, thought everyone shared, why I need to join facebook so I can learn proper etiquette.

When I ask someone what country they are in, most likely I am going to send them at no cost what they are looking for. I have enough stuff to give away at least 25 of the volume controls seen in the video. That includes the PCB. I apologize as my mood disorder often gets in the way, especially when my ankles are getting nipped at. Then someone yells at me... don't pick on that dog.

Posted: 3/15/2019 7:07:22 PM

From: Theremin Motherland

Joined: 11/13/2005

"Two examples that are tested I gave in this forum to discuss." -- JPascal

I'm sure, if you move the 1.5n capacitor to new location between 100p and BA125, the 50/60 Hz  immunity will be improved.

Posted: 3/16/2019 9:50:58 AM

From: Berlin Germany

Joined: 4/27/2016

Thanks, ILYA. Using the first circuit I remember a weak flicker modulation due to r.f. I thought that was caused by the breadboard. 

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