Volume antenna on minimum Theremin

Hello Kultti,
sorry for having been rarely here. Sometimes it happens to me to have to work a little bit in the real life ... ;-)

You may contact me be email: frenkel(dot)thierry(at)orange(dot)fr

I just wanted to chime in to say that I am very interested in this project. I have built an Ultimate 2C (described on oldtemecula.com) and it lacks a standard type of volume circuit. While the optical circuit he gives is nice and simple, I just like the 'traditional' nature of the antenna control.

My electronics knowledge is a bit limited, but perhaps I can learn from your efforts and make something that will work with my theremin.

Feel free to contact me under my email address given above!

Hello milesq,

Just curious about your experience with the Ultimate 2C theremin. How did the loose coupling (i.e. proximity between coils and/or gimmick loop wire) work for you?

Did you wind the "salt shaker" coils or the PVC pipe coils?

Don

Hey Don,

I created the salt shaker coil (I didn't see instructions for the PVC coil in reference to the 2C). I have it mounted at 90 degrees to L1 about 2" off the right side of the board. There are so many conflicting notes and typos in the instructions that I had a very hard time figuring out exactly how it should all be setup. With careful observation of pictures and comparisons with instructions written for the 2B I was able to get it working.

Before I had everything mounted I was able to get a decent tone out of it, but it was very difficult due to placement changing. Now that it's mounted, I have very little trouble tuning it.

Also the 2C includes provisions for a 'tickle wire' which is supposed to help the wave-form, though I haven't tried it yet. I will probably be testing the use of the tickle-wire this afternoon as I am a little bit dismayed by the slight harshness of the tone I'm getting out of it.

Other than that and the volume circuit which I will hopefully be able to figure out from this thread I find it to work quite nicely. With the Lev's Antenna the pitch is very easy to control. I'm no musician (I'm doing this mainly for the electronics experience), but I can play twinkle twinkle with ease.

-Miles

I am having a bit of trouble with the 2C, I think mostly because the directions are really confusing. What is this 'tickle wire' loop? And also could someone post or send a photo of the board close up, with all of the top connections in view? Because I am slightly confused with where the ground/antenna/tickle wire/audio out are supposed to be connected. And is the volume circuit necessary for it to work? I can get the weird swooshing sound on the am radio when tuning the L1 and L2, so I guess I am headed in the right direction. Now to just make the antenna work... This is for a school project by the way, so all help is appreciated, especially because it is due tomorrow...

Regarding the tickle loop on Christopher's theremins:

I am old enough (just barely!) to understand that term. In the early days of radio design, people used a few turns around an existing coil to create what we would today call a "transformer with loose coupling". Our esteemed colleague Uncle Howie can probably elaborate, but as I remember the term was mainly used in reference to adding coupling of a vacuum tube to a LC tank circuit to create an Armstrong oscillator. The "tickling" part referring to the tube periodically supplying energy to the tank circuit to maintain oscillation.

In the case of this particular theremin, the tickler loop is to be put in close proximity of one of the coils to provide a slight amount of signal coupling. This serves either or both of the following purposed:

1. To get mixing to occur at all. In other words, there's no physical part of his circuit that performs the mixer function. Magnetic coupling between coils IS his mixer circuit.

2. Having a slight amount of coupling causes a bit more interaction between oscillators. The end result has an effect on the timbre (i.e. distortion products) of the audio signal.

You might think of this second effect as what happens if you were to take a clean signal and mix it with the output of a distortion pedal for a guitar.

Don

Thanks!
I have it working now :)
although the lower register sounds distorted and can't go too low.

Hello everyone,

Thank you for the great feedback on my Ult-2c. I will put my email address on that slightly secluded webpage. I had a difficult year that caused much of my disconnected thinking to express itself on those webpages. I will add to and reword what I can tonight 6/17 and will be uploading the page several times.

Email me with your questions to guide me in what’s not clear. I will begin with answering rollerguy101 on that webpage. I hate school deadlines.

Christopher

Non Linear Pitch (http://www.oldtemecula.com/theremin/library/danielmccauley/html/drsstc03_01.htm)
.

Thank you so much Christopher. It's clearer now.