I am still not clear how Thereminist in Europe validate their earth ground. In my own research this ground must be direct to the negative side of my circuits or I will not get the ideal wave shape. I learned about really good sound with my vacuum tube oscillators, which by adding a 200v 2uf capacitor between the oscillator and earth ground for DC isolation that this caused unwanted distortion in the wave shape. The earth connection must be as clean and the conductivity as direct as possible. The most beautiful sound is a controlled wave shape.
Edit: In Analog Theremins for the ideal sound and wave shape with ideal Pitch Field response earth ground will not work properly if passing through any components like a diode, capacitor, etc. The oscillators need to be a clean direct connection to earth ground for the natural spiritual interaction with Nature. This is misunderstood by many. I am sure most Thereminist recognize when their sound is spiritually dead so they add a bit of reverb hoping to artificial resuscitate her.
If ground is misunderstood and I send my design into a knowledge pit she would die with everyone thinking it is not their fault. I would rather keep her here in the states so she will live.
That is one of the fun aspects of the sensitivity of theremin design, that it reveals things & behaviors in components that are normally never considered.
Using this adapter how does it get from the European side of 220v & ground to 110v & ground? Is the earth ground on the US ground pin really a clean direct earth ground? One side of our two prong plugs in the states is ground and a bit wider than the other pin. It does not work clean like true earth ground. I think Europe has a safety ground, not sure how that works.
Christopher