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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets.

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Old 1st Dec 2018, 7:44 am   #1
ukcol
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Default Building a Theremin

From my Personal Bucket List thread.

Quote:
Originally Posted by G4YVM David View Post
I love the idea of building a theremin. Super idea...but where to start?
Here is a dropbox link to my theremin folder - I don't think you have to have Dropbox installed on your computer to gain access.


https://www.dropbox.com/sh/npk7a94qn...0Gm_2gfpa?dl=0

If the above link doesn't work with your browser try it without the http:// prefix.



The folder contains articles from various sources and my own outline specification file.
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Old 1st Dec 2018, 12:41 pm   #2
G4YVM David
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Default Re: Building a Theremin

Fascinating. Thanks.

D
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Old 1st Dec 2018, 3:26 pm   #3
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Default Re: Building a Theremin

Are the circuits floating around for any of Robert Moog's Theremins?

David
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Old 1st Dec 2018, 3:31 pm   #4
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Default Re: Building a Theremin

There are a couple of '30s Theramins in the Musical Museum Brentford (London), I wonder if they work and if one could have a go!
 
Old 1st Dec 2018, 4:03 pm   #5
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Default Re: Building a Theremin

Thanks Colin, some interesting reading there. I built a few simple transistor theremin when I was younger with mixed success. I have always thought about building a valve instrument perhaps based on the RCA design - maybe when I retire. I don't think I will ever be able to play one though!
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Old 1st Dec 2018, 4:47 pm   #6
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Default Re: Building a Theremin

Quote:
Originally Posted by sortedradio View Post
I don't think I will ever be able to play one though!

Yes I agree that is likely to be the most difficult part of that particularly project. Perhaps if you happen to be a violinist some of your skills may transfer.
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Old 1st Dec 2018, 4:52 pm   #7
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Default Re: Building a Theremin

Quote:
Originally Posted by Radio Wrangler View Post
Are the circuits floating around for any of Robert Moog's Theremins?

David
Hi David

See file "EM Theremin" added to my link above.
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Old 1st Dec 2018, 5:58 pm   #8
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Default Re: Building a Theremin

If you want as much information regarding the Theremin as is on the web, you might try searching for the Russian name of Leon Theremin, namely Lev Sergeivitch Termen. I suppose the Cyrillic alphabet might help, too.
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Last edited by ColinTheAmpMan1; 1st Dec 2018 at 5:59 pm. Reason: Poor typing
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Old 1st Dec 2018, 6:15 pm   #9
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Default Re: Building a Theremin

Quote:
Originally Posted by ColinTheAmpMan1 View Post
I suppose the Cyrillic alphabet might help, too.
... as in "Лев Сергеевич Термéн".
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Old 1st Dec 2018, 6:17 pm   #10
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Default Re: Building a Theremin

I think in some ways being able to play the thing is the least of ones worries... Tja fascination it will give to guests just by its very nature will be priceless.

D
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Old 1st Dec 2018, 8:17 pm   #11
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Default Re: Building a Theremin

Theramins are interesting projects to build, but most users are reduced to just making 'ghostly' noises due to lack of playing skill, which - beyond the novelty - hardly makes it worth the effort of building one. Here's what a theramin can sound like in the hands of a professional musician, mimicking Gnarles Barkley's song 'Crazy'. As with all accomplished musicians, he makes it look easy. It isn't:

https://www.bing.com/videos/search?q...B0A2&FORM=VIRE

Here's what Gnarles Barkley himself sounds like singing 'Crazy':

https://www.youtube.com/watch?v=bd2B6SjMh_w

Some disinterested cats can play a theramin better than a human:

https://www.bing.com/videos/search?q...1&&FORM=VDRVRV

There's an interesting 1961 'tube' (valve) theramin project with a detailed clear digram of the component layout under the chassis. I had a wry smile at the 'Heathkit style' knotted 2-core mains flex, not otherwise safely anchored, and an unearthed metal chassis. Another example of someone trying to prove Darwin's theory of 'the non-survival of the unwary'!

https://www.element14.com/community/...n-full-article

Hope that's of interest.
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Old 1st Dec 2018, 8:44 pm   #12
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Default Re: Building a Theremin

I've a circuit of the original valve job somewhere. His life story has similarities to that of Tesla in some ways-especially re Government interference and I don't mean electronic oscillations!. His Grandaughter is/was a very well regarded professional player and she appeared at a theatre in Southampton-1994.

I had seen the recent Channel Four Doc re Leon and was keen to go but having been taken ill, I rang up for a program or more details and found myself talking to the Manager. A very nice chap, he said the BBC were coming down that day, mainly to record an interview about Granddad but I ended up with a cassette recording of the concert! It was standard classical pieces, very well executed but not very adventurous really!

Dave
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Old 3rd Dec 2018, 1:07 pm   #13
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Default Re: Building a Theremin

This story long fascinated and amused me- a 20th century revisit of the Trojan horse, perhaps,

https://en.wikipedia.org/wiki/The_Th...stening_device)
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Old 3rd Dec 2018, 2:33 pm   #14
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Default Re: Building a Theremin

Surely when learning to play a Theremin the output volume could be pre-set to give just enough output to comfortably hear so that full concentration can be applied to the tone hand. Learning slowly varying tunes would probably help too. Without volume adjustment it might lack soul but the main idea would be to knock a recognisable tune out.

A bit like learning each hand separately on the piano before the added difficulty of putting them both together.

Maybe it would be possible to modify an audio sig. gen. to effectively give it a try before spending lots of effort on making the real thing although I do understand that the construction of a Theremin is likely to be the end in itself but how disappointing it would be if the builder completely failed when trying to play.

Would ability on another single note at a time instrument be of any help I wonder. Violin, mouthorgan etc.

Is there anyone here who has built one.

Jim
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Old 3rd Dec 2018, 2:38 pm   #15
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Default Re: Building a Theremin

To add to Davids input for the 1961 article, I managed to get some info on the miller coils with a view to reproducing them, but theres not enough information on turns etc. ( attached ).

on the basis that the 3 coils are the same, Ive hand wound 3 coils of 200 turns tapped at 50 turns on some 20mm plastic counduit, on the assumption that the actual oscillation frequency isnt critical. (denco coils may be a suitable equivalent but are commanding silly prices nowadays) However despite gathering the necessary valves and sockets (ebay over a few years ), and winding the coils, the theremin project remains a long way down the to do list at the moment

EDIT. you can buy similar coils. given the inductance value on the datasheet it should be possible to reverse engineer suitable coils https://www.tubesandmore.com/products/coil-oscillator
Attached Files
File Type: pdf miller5.pdf (213.5 KB, 80 views)

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Old 3rd Dec 2018, 3:22 pm   #16
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Default Re: Building a Theremin

The theme from "Midsommer Murders" is played on one.
 
Old 3rd Dec 2018, 10:21 pm   #17
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Default Re: Building a Theremin

I the past I have looked at the designs of many Theremins. In later years many were nothing more than a toy or a gimmick compared to the original valve unit made by RCA in the mid 1920's and could not be regarded as a stable musical instrument, unlike the original.

Solid state Theremins appeared in the early 1960's. Of late modern types have included PIC micro's, OP amps and all kinds of circuit variations.

However, out of all the solid state Theremin designs which impressed me the most, the winner is by far and away the one published in Electronics Australia, June 1969. The designer being non other than Leo Simpson, who went on to become the Editor of the magazine that transformed into Silicon Chip.

The reason is; the circuit is simple, elegant and replicates the performance of the original valve unit. Even the oscillator tank circuits are dead easy to make (buy) because they are 330uH chokes.

I have attached the circuit. But if you wanted to go down the solid state road, I would recommend getting the whole construction article for this 1969 vintage Theremin, which includes the cabinet details and board layout etc.
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Old 4th Dec 2018, 2:41 am   #18
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Default Re: Building a Theremin

Also, a very good demonstration of what can be done with a professionally made Theremin and exceptional skill is shown here, easily as good as any violin/player combination:

https://www.ted.com/talks/pamelia_ku...s_the_theremin
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Old 4th Dec 2018, 7:17 pm   #19
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Default Re: Building a Theremin

Wow!!!

What an amazing musician Pamelia Kurstin is, I have never heard anyone get that sort of performance out of a theremin before. In fact I had started to believe that perhaps the theremin was not capable of great music.

WRONG WRONG WRONG WRONG WRONG WRONG WRONG !!!!!
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Old 5th Dec 2018, 5:17 pm   #20
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Default Re: Building a Theremin

Quote:
Originally Posted by David G4EBT View Post
There's an interesting 1961 'tube' (valve) theramin project with a detailed clear digram of the component layout under the chassis. I had a wry smile at the 'Heathkit style' knotted 2-core mains flex, not otherwise safely anchored, and an unearthed metal chassis. Another example of someone trying to prove Darwin's theory of 'the non-survival of the unwary'!

On the other hand, if there ever was an electrical instrument where safety issues could be considered less important, it must be one that is not intended to be touched!
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