"I'm a complete noob in electronics "
And if you dont get a little understanding about electronics and the effects of voltages and currents on the human body, well - there is a high probability that a "noob" is all you will ever live to be!
1) What happens if I touch the pitch antenna with a power source? How much U and I can the circuitry take without any damage?
Assuming a grounded theremin, there is going to be a 50/60Hz 240/110V signal on the antenna - IF there is an isolation capacitor, this will probably be rated at 100V and could fail short-circuit, such failure could result in your theremins board failing quite dramatically and becoming a new generation of toxic smoke producing E-Cig.
2.) Plasma lamps and HV electrostatics of any kind are likely to kill your theremin.
3.) What would happen if I would touch the pitch antenna with an antenna from another device, say a radio? What if anything would happen if I would start to tune the channels?
If the other device is not outputting signal (is purely a reciever) then its UNLIKELY for either device to be damaged, but probably not impossible - as to effect, loads of things will need to be known to have even a chance of predicting results.
4.) Can the pitch antenna be changed easily to some other type (how)? i.) Could I just use a piece of copper wire and put it in to a bucket of salt water and then use the bulk of water as the antenna? ii.) What about a solenoidal or toroidal antenna? iii.)
Yes, all the above are within the realms of possibility - But whatever is connected will need to have the same bulk capacitance as the original antenna, unless you want to open up your theremin and re-tune it - If you want to play with this sort of thing, best to get a Jaycar / Silicon Chip theremin (or even something simpler, like one of the Harrison theremins), as their tuning is far less critical than the EW (they do not have a linearization inductor and therefore one can more easily change the capacitances / frequencies of the oscillators) and you can add / remove capacitance to taste.. I would be happy to swap your EW for a theremin better suited to experimentation (and would add extensive protection circuits including HV coupling capacitors and discharge tubes) - I will even pay all postage costs.... ;-) ... But I would not provide any warranty!!!!!
I am also herebye launching a new society - the society for prevention of abuse against quality musical instruments SfPoAaQMI, And strongly urge such abusers or those who feel inclined to such abuse to exchange or donate their threatened instruments to a caring home..
5.) Is there a way to listen my own body functions? It would be awesome to actually hear my own brain waves;
Yes, that could be awesome! - particularly with a brain like yours! ;-) .. No, no simple way to convert a theremin to an EEG or ECG - And for both such devices EXTREME caution is needed WRT design and implementation.. For any home / hobby device, EVERY component (this includes audio amplifier etc) MUST be powered from and connected ONLY to equipment powered from a low voltage battery supply, Adittionally a resistor (or other current limiting component or circuit) must be inserted in series with any body connections so that no more than 1mA could ever pass through ECG leads, and no more than 100uA could ever pass through EEG (head) leads.
This whole area is NOT NOOB TERRITORY! - It is the kind of stuff utterly reserved for COMPETENT TRAINED ENGINEERS - I was not allowed to design such equipment until I obtained a Msc in Medical Physics, my Bsc in electronics was insufficient - And until I was certified by IEEE as being competent, all design work I did required verification by my superior who was a chartered (Medical Physics / Electronics) engineer.
(I should just add that, even after certification, schematics were always examined by other engineers - Even my boss who had many years of design, would always ask me to check his designs.. The designer took full responsibility, but the concequences of any mistake are so serious that only a fool would assume they are incapable of making an error)
Some of the stuff I have seen published on-line makes my blood run cold.. These days there are good (but expensive) isolating amplifiers and the like which greatly simplify design and reduce risk - And battery powered devices can be safe IF they are isolated from all external equipment - But in the hands of incompetents, even these can be fatal.. they are only safe IF instructions are followed to the letter - And instructions rarely are, particularly if the device is used by someone who may never have seen the instructions.
6.) What happens if I join the volume antenna with the pitch antenna using a copper wire and try to play with it?
Might probably be safe to try, but it probably will result in silence from an EW.. Its a completely pointless thing to do.
7.) What things will wreck the tuning or something else? How to prevent it from happening due time?
Everything you have suggested is completely daft, and has the potential to damage both you and your theremin and any other equipment you use in your experiments.
8.) If I start to play immediately after shower (when body conductivity is something like 1000x higher), how will it affect the sound? What would happen if I then touch the antenna and for example a grounding wire or a small electric source (with or without touching the antenna?
If you understood capacitance, you would understand that your "wetness" or "dryness" will make almost no difference - Dry skin simply forms an additional dielectric of perhaps 1mm for the capacitive coupling, and thats insignificant.
It is your ground coupling capacitively coupled to the antenna which determines pitch, any other low frequency superimposed on you is unlikelt to couple significantly.
Read the EW technical manual, learn some basic electronics, and learn to value your life (and more particularly your health - Believe me, if you lose your health, if you end up in permanent pain or with severe disability resulting from some stupid action, you wouldnt thank me if my posting had been encouraging!) and your fine musical instrument.
Fred.
I think perhaps you utterly misunderstand the theremin - it does NOT work by detecting signals of any kind from the body - it is simply a capacitance sensing circuit.. You are a moving ground-coupled capacitance 'plate' which acts with the antenna to form a variable capacitance to ground - THATS IT!
