ThierryMin 2020 Perfectly Linear?

Posted: 5/26/2019 8:04:31 PM
oldtemecula

From: 60 Miles North of San Diego, CA

Joined: 10/1/2014


After this subject was brought up in another thread it made me wonder… could the ThierryMin also have a perfectly linear pitch field. Being this is a popular build, what a nice feature that would add.

If this works you will be able to develop your pitch arm technique with precision playing like using a $6500 Epro but for under $50. You can add any of several other proper volume control methods later, which are a little more complicated but still under another added $50.

Major Edit: I have always avoided using FET's. What I found in building the ThierryMin is linearity is possible at 450 khz. I was only getting three octaves max using the FET as they seem too gentle and I need much more energy driving the Electrodeum to get five linear octaves, this is a clue. Also with FET's I have no control over thermal drift which can be eliminated using NPN transistors, I will show you how. I did learn a lot from the ThierryMin build and will post a video of the FET two or three linear octaves I was getting by the end of the week.

I have already laid out a new board design using NPN's and will post that also this week. I do not model so I can experience electronics that work in reality.

Using NPN is still as easy and cost effective as building the ThierryMin for $20 and would recommend this in the future. I will create a webpage for it all.

When designing and building do I hear the theremin sing, in a way I do, want to hear Gabriel's Oboe, has any Thereminist tried this tune. 

Christopher   

This is the original ThierryMin


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Posted: 6/3/2019 11:08:52 PM
oldtemecula

From: 60 Miles North of San Diego, CA

Joined: 10/1/2014


Did a major edit of the thread. Stay tune for more coming soon!  Read original post above.

For the true ThierryMin, would use different horizontal coils which will be on a Mouser one click parts list

Use the recommended two 3.3pf and not the vertical orange striped coil, pcb toner transfer will be available, something you should learn to do.

The only test instrument you need is an AM Radio tuned to the 900 khz harmonic. 

This will tell you if the oscillators are working and which one to move up or down by tapping your finger on the coil, they must match in freq.


Posted: 6/5/2019 10:55:56 PM
oldtemecula

From: 60 Miles North of San Diego, CA

Joined: 10/1/2014


The best thing I learned from the ThierryMin build is not to be afraid of variable capacitors contributing to thermal drift. I will do more testing. The layout of the ThierryMin schematic showed me how to layout and do something similar with the NPN transistors which I call Deep Throat. I did see that movie in the early 70’s with my wife and the only seats available were in the front row. OMG

Using a low value variable capacitor opens up analog design to more possibilities. For sound it is the upper end that most reveals the beautiful voice. Using high current inductors I think might create a better sounding low end.

Here is a never heard before Valery S in St Petersburg Russia warming up the Phoenix 2020.

The First Warm Up mp3   This is the Phoenix not the board below but it could be.

Below could start out as a beginners first build for about $35, then expand later. Have five perfectly linear octaves. Pot-3 1k set halfway is where thermal drift nullifying happens working with R9 470R. Discovered this 10 years ago, no one was interested as we were all doing our own thing. My designs do not have any thermal drift issues.

The two smallest drill bits are on Mouser List.     .9mm & 1.2mm

Edit: Mouser charges extra $7 per order so not worth splitting into two orders. Mouser Parts List  Get transformer and Electrodeum spring at Amazon at a future date, not really needed immediately for your theremin build.

An add-on proximity volume control can be added later for a theremin < $100 with a perfectly linear pitch field that matches or even better than an $6500 Epro.

Visit www.Hwy79.com

I have no name for this 2020 theremin below as it is from parts of all of us going back ten years. Yes it is good and could be the best if you can hear.

Experiment: Would like to lower the 4.7k value of R8 & R20 to drive more current into tank, if five linear octaves then why not seven? (Tesla Coil?)

You will notice I am using induction coupling through the 1N914 diode detector. This was revealed two weeks before the Phoenix was sent to Russia.

Christopher


100mm x 100mm

If there is any interest I will post the PDF toner transfer files along with Gerber so you can take advantage of the JLCPCB bargain if it is one. They avoid mentioning their setup charge up front. Also I want single side 2 oz copper with no Visas. This is better for part removal when experimenting.
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Posted: 6/11/2019 4:50:51 PM
oldtemecula

From: 60 Miles North of San Diego, CA

Joined: 10/1/2014


In both of my evolving ThierryMin board designs above you will see the letters LDR. This is not some church in Utah rather a clever method of Volume Control. With this method your pitch arm can develop proper technique if you solder the LDR onto a two meter length of TRS cable for remote access. You could solder the LDR on the board directly for table top finger pitch popping but that might restrict your pitch arm movement.

If someone says that is not a theremin… then agree, we will call it Electrodeum Fingering, much more natural with a perfectly linear pitch field.  Listen to the control this simple $1 method allows. I have a bag full of about 100 of these and if you do not have one then remove one from any bathroom night light that goes on only when dark. The better LDR's will quiet the sound completely.



Edit: The above 100 x 100 board at the #2 TRS LDS jack my excellent Phoenix Volume proximity control will adapt and plug right in. You would have a theremin with a perfectly linear pitch field using the Electrodeum Electrode making it very comparable to an $6500 Epro for about $100. Use an old EtherWave Standard box with hardware.

Christopher

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