"Build the EM Theremin" - altered component placement - comments?

Pitch antenna length

Hey, I've read somewhere, might even be in the forum, mentioned that for the newer,  3-coil (EQ) etherwaves, the pitch antenna was shortened, from about 46cm to about 40cm. It seemed a more casual remark and no references were given.

Can someone confirm this?

hi tinkeringdude,

long time no see. :-) don't know about any shorting. just to let you know:my 3coiled etherwaffel has a 45cm long antenna, ø:9.6mm. all original.

already finished yours?

Ah thanks, so no extra sawing ;) Wonder where the other guy got that from then, though.

No it's not really finished. But in a while I will, I now got wood parts for a nicer case, and a metal front plate (no holes yet & not yet bent). An aquaintance bent the volume antenna for me, looks pretty decent, now I have to decide whether to put some shrink tube on it, I guess since the bent one is copper, which is known to be oxidation-happy, it would be a good idea (next to the touch thing), eh?
Although the straight antenna currently is brass, which looks quite nice as it is.
Hah, maybe I'll first polish the copper one, then put transparent shrink tube on, and it'd look more similar to the brass (compare to, say, black shrink tube ;) )

I think insulating both antennas is a good idea as I believe it helps to reduce ESD damage.  It also keeps things purely capacitive by maintaining a gap between your hand and the antenna at all times (so pitch change when you touch the antenna will be somewhat less).

Antenna length doesn't seem to be a huge deal, though of course it will influence the tuning point if you go changing it.  From my own experiments I believe longer and thinner antennas are best for Theremins without pitch EQ coils (in terms of linearity and perhaps heterodyned sensitivity).

something i wanted to ask since long and was always afraid of :

instead of shrink tube: anybody ever tried zapon? good name isn't it? it's an old kind of laquer for metal, a firnis based on kollophonium and some different alcohool. finally transparent and shiny. just because you mentioned polishing both antennas and then hide the beauty behind rubber.... zapon-lack, esd and antennaeiou ...time for bed. :-)

Zapon is fine. It was used when I had to build replacement antennas for a Moog Series 91A Theremin. I decided to have them made from polished and zapon-laquered brass by a wind instrument maker.

That looks quite nice indeed!

Also interesting, how the "hoop" part of the antenna is so much more pronounced compared to the etherwave.
I've seen doubters in this forum as to whether this shape of antenna is really "needed". I imagine it is to give the volume hand more effect further way from the pitch antenna (reducing "control crosstalk"), and making the hoop easier reachable since it's also pointing towards somebody standing in the center in front of the instrument and thus does not have to put the wrist at too much of an angle to the arm (straining) - is this correct? I'm not a theremin player, yet :-)