Theremax coils

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

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.
http://vinic.free.fr/tmax/

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 www.audiofanzine.fr forums ('les mains dans le cambouis>Theremin') aboout theremax construction... More than 80 pages for the braves! ;)

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

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
vinic

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
robonil

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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