The theremin, a musical Instrument from to the birth of electronics. . .

 
Tube Warmth - Altermen

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The Vision of 2003 . . ."True beauty is hidden in Simplicity"

Clara Rockmore is the #1 theremin virtuosa, but how did Lev Sergeyevich
 create her "authentic" golden sound?  

11.03.14   My 12 year theremin journey seems to be winding down. As time passes I begin to forget details. People seem to gravitate toward the digital stuff today which for me misses the point... which is the connection with the past. The most important aspect I think is that authentic fat sound... not a synth sound or nine octave whistle buried in reverb, you get that from a keyboard.

The Altermen Authentic.wav  2 megs  This is Altermen direct to sound card, no acoustic development.

I designed a single tube theremin-like hybrid instrument that has the Classic Sound, Drift Resistant and a Perfectly Linear Pitch field. My standard proximity Volume Control can be enclosed separately so it can be placed anywhere around you. This hybrid Pitch setup with Volume Control can be built for less than $200

It uses three 8.2" x  3" circuit boards and one click Mouser component ordering. Everything not at Mouser like the one vacuum  tube with  tube socket I could send you at no cost. I have accumulated a lot of the right stuff over the years doing my research.

My goal is to find a handful of competent builders here in the States for this project. I have nothing to sell, it is for the love of the Art and honoring those that came before.

Returning to Tube Warmth (Nature)

Share with me your building skills, you just might be invited to build the Altermen

theremin@oldtemecula.com

Maybe trade your good wood skills for my giving you 3 PCB's with the complete tube section in parts?

Design a simpler Volume Control PCB layout PDF when it is not used separated from the Pitch section.

Also it would be great if you built this for someone and sold it to them for $10,000 (-'

My hybrid pitch side uses one of these osc boards along with the Phoenix Pitch/Volume build to get the authentic sound.

My last project was to breadboard a hybrid Tube/Valve pitch oscillator and see if "Perfect Linearity" could be found. This would clarify if the phenomenon of LINKS and the Lev Antenna was unique to transistor oscillators or could it also be demonstrated using a tube/valve oscillator. 

The answer is Yes!  "Perfect Linearity" happens with vacuum tubes!

Most of my theremin experiments over the years used Hartley Oscillators operating between 800 kHz and 1000 kHz. This higher frequency allows the design of the Lev Antenna to be more practical. I found that using hand wound air coils in the oscillators was a poor choice because it limited Perfect Linearity to just over three linear octaves and added to pitch drift. Experimenting in real time demonstrated that using High Q ferrite coils would give more than five linear octaves, more than using air core coils. 

A pitch oscillator around 922 kHz and the Lev Antenna creates linear excitement!


With my musical crudeness in a 18" pitch field in the sample below I will make a one octave jump by closing my fingers then rapidly opening my fingers within 1" of the pitch antenna. I will repeat this while moving midway back in the pitch field and then near the lowest octave. Each time the same hand/finger movement is used. This is one of the easiest methods of validating any theremins pitch field linearity. I am watching a frequency counter.

Linearity Test.mp3 (200k)
Raw vacuum tube sine wave  
A linear 2400 hz down to 50 hz

Perfect linearity remains no matter what size intervals or octave widths you enjoy playing. This Lev Antenna phenomena once set does not need retuning. It's tuning bandwidth is broad and stable.

My scratch built hybrid theremin uses one vacuum tube on the variable oscillator antenna side and does not use variable capacitors. It uses simple solid state tuning, the tuning knob could be twenty feet away.
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This tube/valve hybrid build begins with the Phoenix Solid State. Pitch and Volume use one each of the same board with minor parts differences. Build these two boards first then add one tube/valve osc board.

Most of the parts you purchase from Mouser. 

This Altermen could become one of the most treasured theremin designs,
 it dispels 13 common design myths.
 

Horizontal pitch antenna is called "The Abbot" it's more natural in playing but you could use it vertical
It is played below your shoulders with the normal forward downward arm movement with aerial fingering.
It makes better use of perfect pitch field linearity by changing the angle of play.
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The Altermen is basically three PC boards mounted on a Mic stand
Photo Not Up to Date, One Transformer, Tube & Board Eliminated

On the right side of these two 922 kHz osc boards you can see the small IF transformer coil, no big coils are needed! The entire hybrid pitch section is made from two 3" x 8.2" pc boards . The remotely  located Volume Control uses one 8.2" x 3" pcb. The entire design operates from a single 115v isolation transformer which powers everything.

I posted a list of 13 theremin design myths to TW once but the engineers got too upset for me to post it again. The forum host needed to delete what I suggested, it did not support the current engineer models? In theremin design you must allow the theremin to guide you as she will show you most often what does not work and that most methods have an un-musical sound. Modeling relies too much on possible GIGO which does not encompass all the circuit influences found in analog oscillator design. That is why engineers and their models rarely do hands on construction or post sound bytes. They insist modeling saves time. o-;  

Some electronic engineers spend too much of their time working on the negative issues they create. They over analyze rather than do real world hands on testing. She (theremin) has attitude and if you're not invited she will make you suffer. My journey was tested by fire and not by her... rather the engineers I tried to interact with. To often in their arrogance they call the efforts of others rubbish because they have no clue how difficult theremin design can be. Judge someone's success by the sound and response they get, not the purty pictures and graphs they post.

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