ThierryMin 2020 Perfectly Linear?

Posted: 5/26/2019 8:04:31 PM 1

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.

Christopher

This is the original ThierryMin using two 3.3pf caps without my L3 Choke

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Posted: 6/3/2019 11:08:52 PM 2

oldtemecula

From: 60 Miles North of San Diego, CA

Joined: 10/1/2014

threads - posts

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: 6/11/2019 4:50:51 PM 3

oldtemecula

From: 60 Miles North of San Diego, CA

Joined: 10/1/2014

threads - posts

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.

Finger Control .mp3

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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