Tube/Valve Tannerin/Ondes Martenot

Posted: 12/5/2018 6:00:52 PM

From: Northern NJ, USA

Joined: 2/17/2012

"I think we all appreciate how much performance and functionality you can pack into a digital design, but along with that low cost, feature-laden capability comes the baggage of software and impending component obsolescence that can doom the entire product to the landfills in a few short years."  - pitts8rh

This is something I do very much worry about.  Though if the hardware - including processor - is defined in a higher level language that won't soon disappear, then the portability and therefore survivability factor goes up.  Just as we paw over tube Theremin schematics for clues, future Theremin designers may paw over the code to see what makes it tick.

I'm wondering if it will even be possible to build / repair a tube Theremin in 40 years or so.  Almost all electronic components disappear over time, not just the digital ones (though they do seem to disappear at a faster rate).  Are most tubes for sale these days (outside of guitar amp tubes) vintage surplus?  If so, then that supply will dry up at some point.

"And as far as analog skills being arcane (!)..."

I was talking about tube skills there, not analog in general (of which digital is certainly a subset).  I don't have any tube skills to speak of, with no plans to pick up any beyond the osmosis of reading the odd project here and there, though I can appreciate those who do.  I imagine much the attraction of building a tube Theremin is to have a benchmark of sorts, to gain direct experience as to what the heck the original even was.

Posted: 12/5/2018 6:22:46 PM

From: 60 Miles North of San Diego, CA

Joined: 10/1/2014

In an approach I discovered some thirty years ago, my original experiment was finding the simplest method of creating a musical sound electronically with solid state. My friend Paul was also interested as there can be excitement in simple creativity.

This is Paul’s Box as he called it from another era, he is a musician who knows nothing about electronics, he needed help from some friends, not me.

Square waves or triangle waves do not sound musical to me no matter how many you mix together or they sound funny. Also if I create a sine wave with vacuum tubes or simple transistors using heterodyning I can not tell the difference between them in a blind study hearing test.

I think in Creative Art it is ok to fib a bit, generate the sound one way but create an elaborate visual scheme using tubes or what not for the visual illusion. Hum… sounds like the midi people.

I mentioned in this forum before how just passing a sound wave through a light emitting diode and picking it up with a phototransistor can enhance or distort it just enough that a sound wave that is boring can become musical. IMHO

I learned in my baby making days that a little teasing can be more fun than you know.

This approach uses 4 ma so could last years on batteries and there is a DIY circuit board PDF to etch.

Another observation I have made, if a note sounds good while sliding, it sounds much better plucking like the piano.


I am sliding optically though you can use a 100k Potentiometer

Posted: 12/5/2018 11:39:26 PM

From: Switzerland

Joined: 11/5/2018

Dewster, I mostly agree with what you said before. If I would make a digital theremin, I would use a DSP processor, because they are optimised to make real time signal processing. Some models are very cheap and include both one or more DSP and a general processor as well. I also think I would not use radio frequencies but light. It is devices on the market, I forget their name, which scan a 3D area with a laser and can be used, as example, to control the speed of a conveyor belt according to the demand, as example the number of peoples in an airport. Light is very interesting because with a laser, you get a single frequency light which is immune against possible external perturbations and can be used to scan a 3D area in real-time, which will add a third dimension to the theremin.

About the obsolescence and repairing old equipements, it is much easier to replace a vacuum tube or a transistor by one of another type, than to replace a microprocessor, or any other digital parts, by one of another type. With tubes, not only guitar players and audiophiles are using them, they are used in radars and telecommunication as soon the output power is more than a few hundred watts, and many armies use them into low power telecommunication equipments because they resist to nuclear radiations. That imply you will still find a lot of common low power tubes in 40 years, and not only the ones used in audio but also the ones used in telecommunications. Even if I am wrong about that, a theremin work at less than 1 MHz, which imply it will always be possible and easy to replace a high frequency tube like the ECC85 by an audio tube like the ECC82 or even an EF86.

It is also another concern about tubes vs transistors vs digital obsolescence. The silicium made possible to build dedicated types of parts at a relatively low cost, and these dedicated parts will have a very short life on the marquet. Typically, they are manufactured at the same time than the device, they will make maybe 10 or maximum 20 % more parts than needed to manufacture the devices, and a few years later when their space parts stock is empty, they will just say they are sorry but these devices are impossible to repair. Such dedicated parts include not only digital chips, but also analog parts like output transistors, special sized condensators, transformators, potentiometers and so on. More than 10 years after the manufacturing of such amplifiers, you are very lucky if you can find such transistors and they have no equivalent types. I was working more than 30 years as a repair man, so I know it very well. The US army is even manufacturing depleted uranium semiconductors for their satellites because they are much more temperature tolerant than the silicium ones, which allow to run them both faster and in more extreme conditions. And obviously, you will not find them into the market. At least not today, but they have so much DU and just don't know what to do with it.

Posted: 12/6/2018 1:33:06 AM

From: 60 Miles North of San Diego, CA

Joined: 10/1/2014

Just enjoy sipping my Glenlivet 18 Yr old scotch. Problem is it makes me a little cranky. I see this particular thread as sacred.


Posted: 12/6/2018 6:11:49 AM

Joined: 11/25/2017

often I have thought if I offered Jason $10,000 would he delete just one thread at TW that I think derails TW from what the spirit of theremin is all about.


Posted: 12/6/2018 8:42:44 PM

From: 60 Miles North of San Diego, CA

Joined: 10/1/2014

gerd, it is better you quote me as I was deliberately low balling the amount I would pay.

My method of making things is to try any and everything I can think of, to discover something others may not have. I have nothing against digital vs. analog rather it is the attitude of the computer modeler against the bench explorer. As I say throughout my postings, get a sound sample of anyone you want to mimic before you start to build. Digging a musical sound out of noise is tricky. I have learned what sounds musical to one may not to another. Everytime I put up a sound byte it is a risk, wonder if people are enjoying themselves or just laughing?  I will drink to that!


Twenty years ago some of my stuff went into a special project for kids.

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