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Old 4th Jun 2008, 4:08 pm   #21
Pete_kaye
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Default Re: Ever built a theremin?

there was an item on Radio4 today about 9.00am,'Midweek' withthe daughter of the inventor demonstrating in the studio .you can listen again.
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Old 28th Jul 2008, 2:42 am   #22
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Default Re: Ever built a theremin?

The reason noone builds a Martenot is because it is virtually impossible! Very few people have circuit diagrams, and even if you did, there's more to it than that. Certain parts were custom made - of course, it could be replicated, but few people know exactly how it functions. The reason it is such a rare instrument is that Martenot hand-built them, and each one took a long time. Getting hold of one now requires 1) being in a particular circle 2) speaking fluent French and 3) having wads of cash! Even Jonny Greenwood had difficulty finding his - he phoned my friend and asked to borrow his for touring! Naturally, he told him where to go!

There is a French guy who spent many years building something as close to the Martenot as possible. The result was given the thumbs up by top Ondistes. However, this took a long time to build, at great expense. If I remember rightly, you'd need £10,000 to buy one, the patience to wait a couple of years for it to be built (plus the queue)... in fact, he doesn't even respond to queries now, I'm led to believe. A shame, as I would love to try one!

I came across some old Theremin circuit diagrams the other day. Unfortunately, they'd been eaten by mice so I threw them out! If anyone's interested, I could see if I have any around, still. As was suggested earlier, though, the Theremin World site has some circuits, and info on where to find more:

http://www.thereminworld.com/projects.asp
http://www.thereminworld.com/pubs.asp

Perhaps, if you want to go for a classic valve Theremin, you'd find the old RCA service manual handy?

http://www.vcomp.co.uk/manuals/there...ice_manual.htm

Lots of links here, but you may find some sites no longer work (try archive.org, though):

http://www.thereminvox.com/link/category/26/

Hope the links are of help!
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Old 28th Jul 2008, 10:19 am   #23
paulsherwin
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Default Re: Ever built a theremin?

Please don't start discussing all sorts of weird and wonderful electronic instruments in this thread folks. It's about theremins and closely related technology.

Paul
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Old 1st Aug 2008, 8:11 pm   #24
Jack Spark
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Default Re: Ever built a theremin?

Hello all. Newbie here, first post and everything.

I am looking at the posibility of building an RCA theremin, seems to be loads of stuff on the net and I have all the valves.

Am no stranger to electronics but this is my first valve project so if I don't use the right lingo please put me right!

So, already have the power supply, can anyone supply or reccomend a source for suitable valve bases/sockets? The thing uses UX and UY type valves 4 and 5 pin.

Next question is about coils, is there anyone who can wind these or suggest a suitable DIY method?

All advice gratefully accepted!

Thanks in advance.

Jack
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Old 2nd Aug 2008, 6:33 pm   #25
Ed_Dinning
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Default Re: Ever built a theremin?

Hi Jack, if you can post the details of the coils we may be able to advise. There are several firms who make them TOKO comes to mind and these will be available from distributors. If you want to wind your own then Scientific wire co can supply the enamelled wire.

Ed
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Old 3rd Aug 2008, 8:51 pm   #26
Jack Spark
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Default Re: Ever built a theremin?

Hi Ed
Thanks for the reply.
Coils, it uses 5 coils in all, 2 are wound on a 3 inch former:

One has 1350 turns of number 33 AWG magnet wire 39 millihenrys with a DCR of 39 Ohms. The other has less windings and I can’t find the data on it at the moment!

The other two coils 85 turns of number 30 AWG magnet wire 598 microhenrys on a 1.75” former with another winding in the opposite direction on top separated by some tape.

There is also a smaller coil but I won’t worry about that at the moment.

Any help?

Thanks again

Jack
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Old 4th Aug 2008, 9:49 pm   #27
Ed_Dinning
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Default Re: Ever built a theremin?

Hi Jack, this sounds like a winding machine job. The normal manufacturers mentioned above all make small ferrite cored coils. The inductance figures given can be found in these ranges but the DC resistance will be much lower and they may not work in your circuit.
As long as they are not wave-wound they should be easy, if tedious to replicate.

Ed
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Old 5th Aug 2008, 8:14 am   #28
Jack Spark
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Default Re: Ever built a theremin?

Thanks Ed

I was afraid you were going to say that and have already been researching coil winding machines.

Anyone already have one capable of doing the job or is it more DIY for me?
If its DIY, can anyone suggest any suitable and useable designs?

Thanks again.

Jack
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Old 5th Aug 2008, 11:07 am   #29
Dave Moll
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Default Re: Ever built a theremin?

There are members of this forum with coil-winding equipment, but I would not wish to put anyone on the spot by mentioning names.
__________________
Mending is better than Ending (cf Brave New World by Aldous Huxley)
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Old 5th Aug 2008, 12:29 pm   #30
Jack Spark
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Default Re: Ever built a theremin?

No thats fine Dave, I wouldn't expect you to do that, but I am looking for a volunteer!

So is there anyone out there who is willing and able to wind these for me?
eedless to say I will send the formers and cover all costs.

The coil winding challenge begins!

Thanks

Jack
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