Theremax coils

Posted: 4/19/2006 8:08:28 AM

From: France

Joined: 4/10/2006

I forgot to mention that thanks to your help, I managed to build my theremax!

so... BIG THANKS! especially to Colin and dvanhorn.

I posted some pictures and documents here.

I have to take the time to solve two problems. Surely they are now solved in this forum... I'll have a look but I didn't come here since... wow... I have much topics to read!

First is that I get that whistle from volume oscillators into sound. I've tried to reduce filter frequency (the one after detection) but it didn't work... I may look further into schematic.
Second is that volume antenna nulling point is way too narrow to be playable.

Nevertheless, I really do appreciate the Theremax sound, it has real personnality!
France thereminization is steping forward!

By the way, there's a very interesting topic for french talking people in forums ('les mains dans le cambouis>Theremin') aboout theremax construction... More than 80 pages for the braves! ;)

Wave of hand
Posted: 4/19/2006 10:16:17 AM

From: Kansas City, Mo.

Joined: 8/23/2005

(Copied from a post I made back in September 2005)

After tuning the pitch oscillators, before you remove the VCA jumper, go ahead and turn the adjustment on L4 and you may find a place where L4 interacts with the pitch oscillator. Adjust L4 to a position where the pitch is stable as you move your hand to and from the volume antenna. Then, remove the jumper and tune L3 to achieve your desired volume response.

Good luck with your Theremax and happy Theremining!
Posted: 4/19/2006 2:24:24 PM

From: France

Joined: 4/10/2006

Thank you kkissinger!

Actually, this quote is a quite from the theremax instructions book from Paia... I did that... but that is not my problem.

My pitch is stable and volume antenna/oscillators don't 'interact' with the pitch oscillator. My pitch is stable when I move my left hand. And volume works fine so far.
but what I hear is another thing. It's a frequency around 5 kHz (high whistle), mixing with the (stable) pitched sound as I move my left hand, as if a harmonic frequency was interfering somewhere, acting like a second theremin but with the volume antenna.

I guess this is an alimentation trouble (at least, that's my next investigation track!). As I use a small switching power supply unit, which are very noisy ones, I may add some capacitors on several alimentation points to filter that noise, mainly close to oscillators. I'll see...
Posted: 11/11/2006 8:24:00 AM

From: santiago, chile

Joined: 3/17/2006

Thanks for the all document of theremax!, ive been searching for a long time for those ones, im gonna work on it, thans again vinic!

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