Help, my Theremin is polyphonic.... (Jaycar)

Meanwhile I found out that the SC Theremin absolutely needs to be grounded, even though the design does not suggest it. With the rod antenna the sound got much worse, ie. the LF enters through the antenna not the power source.

If you use it as designed with the tiny speaker and the flimsy antenna you will only notice that the sound is annoying. Only through a Korg Pandora and a headphone it shows that there is actually a problem. With a proper antenna and linearization the SC Theremin is useable (I have 2' range now with the antenna flat on the table) so if I get the sound right it will be a real instrument.
Since I need the ground anyway I will try out if it tolerates an internal transformer. Oh, and I found that a fat broadband speaker does not mess things up too much and is actually fun, so I'll try to have that too.

So, as a thank you to all of you, here is a picture of my finished (well almost) Theremin:
Dirks Theremin (http://www.djuga.net/tmp/DD_Theremin.jpg)
It is equipped with an internal speaker and an extensible, removeable (plug-in) pitch antenna from the Theremin pitch antenna shop.
Only modifications of the kit are adjustable pitch range, range linearization and mains power. And of course the internal speaker is not the one that came with the kit..
The circuit would benefit from a Low Pass filter. In my design this is effected by the speaker speaking to the table :)