Reading EM theremin schematics

Posted: 8/3/2017 11:21:00 AM
rupertchappelle

Joined: 5/8/2017

I would pay attention to xtheremin8.

Posted: 8/3/2017 2:05:48 PM
Thierry

From: Colmar, France

Joined: 12/31/2007

"Thierry is an excellent source."

Huh? Rupert??? Thank you!!!

What our young builders should understand, is that there are reasons why the Moog Etherwave Standard Theremin (a slightly improved circuit compared to the EM-Theremin) is build on a double sided PCB. Parts of the circuit (not all) are very sensitive to parasitic capacitance (as most RF circuits) which is easier to avoid by short crossing strips than to have longer strips in parallel.

The Wavefront Theremins which are based on that EM circuit, too, using a single-sided PCB, have never reached the pitch range, linearity, and decent volume response of the Etherwave originals. The latter might be naturally unimportant considerations for young enthusiastic students without any idea about how a professional player will "feel" the instrument.

But my inner perfectionist insists on every future theremin builder becoming first a good thereminist, having lessons with one of the renowned players like Lydia Kavina and Carolina Eyck for a few years, before they acquire the needed sixth sense and may start building their own instruments.

 

Posted: 8/3/2017 3:56:07 PM
rupertchappelle

Joined: 5/8/2017

Thierry, if you had made that bass improvement module several years earlier I might not have ever bought the Harrison Model 302.

And a certain person would have been correct about my theremin skills.

/rimshot.

You are impressive. Bass on a Etherwave?

Fantastic!

Posted: 8/7/2017 12:27:48 AM
RoyP

From: Scotland

Joined: 9/27/2012

For what it's worth, this is where I started: Art Harrison 145 from a few found bits and more bought components. It never worked first off and I had to contact Art and to his credit, he persevered until my (stupid) mistakes were ironed out.
There is nothing like getting a project to work, even if it isn't in a box but spread out on a table better used to fix violins!

Subsequently, Art kindly provided me with alterations so that I could alter the 145 so that it responds like a traditional instrument.

I gave it a rod and a bent volume rod on a whim, and they worked.

Although my main instrument is now a modded EW, I still play the 145 and enjoy playing it very much.

The 145 is my icon image :-)

(Image of the 145, guts hanging all over the palace is in the images folder 'Open Theremin', it's the only pic there with everything hanging out, as it were :-)   )

Posted: 8/8/2017 3:31:16 AM
xtheremin8

From: züriCH

Joined: 3/15/2014

what a cool picture! my first diy squeeky theremin noises came from a minimum theremin, and that was such a great experience! got me completely hooked to the instrument. and one has to start somewhere. (i would start with a thierrymin, if i where at the same point as back then.no cmos but basic theremin, sounds and behaves much better, only a few parts and no mind-expanding noodling with all those wires i used. that makes me still a bit dizzy in the head.)

after all i think, building a theremin is not that very difficult, but building a good one is. i guess many handknitted theremins end on the shelve someday, because they are not good enough. 

blind silly me, i never noticed how close the wavefront is to the em-theremin. oh dear. you're so right thierry, as mostly always, about the flaws of it. took me a while to figure it out, but i had to do it...... maybe i put a espe-module into it...? lol. 

this is just my thinking as a tinkerer, but improvement of the em-theremin seems possible, to compare it with a newer design the etherwave hot rod manual is the source for that, maybe integrate the bass extension module into the design improve the layout maybe a bit, keep thierrys hints in mind, and finally fall in love with your instrument.

it's a musical thing. nada brahma.

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