08.04.07

Hello Christopher,

I feel I have made a useful discovery....you may know of course.....

I unplugged my theremin (a Jaycar one) from the main 60Watt amp so I could hear the bigger internal speaker I had fitted. It went crazy - the sound went off tune and broke up into an awful noise.....almost like a stabbed pig!!!

So yes - Theremins NEED an earth and my twin wire wall wart did not provide one.

However - the picture shows the Theremin on the old heavy mike stand which I use. The metal upright rod fits nicely into a brass bush which I made and silver soldered onto a small mounting plate. The bush protrudes into the box about 1.5 inches. It just lifts on/off - a sliding fit.

Now the useful bit - using a small 3 inch crocodile clip lead, I joined the negative PCB rail (actually from the audio out socket), which we often call earth?, to the brass bush - hence the metal support pole.

And voila - there is the lovely Theremin sound - just about completely restored and very playable.
This opens up the possibility of battery power and portability.....

Perhaps it can be considered that I am making a dipole antenna - but whatever - it replaces the function of earth. You may also note that my floor mat is actually plastic. {My garage floor has been known to flood!}

I shall proceed with your design again shortly and may try and use the volume circuit from the Jaycar - it works well as modified with the standard? loop aerial....A volume control is a must for me.

Regards
Dave W.