static electricity spark now etherwave is silent

Posted: 2/14/2014 11:03:35 PM
Bob Klips

From: Columbus Ohio

Joined: 1/17/2014

Glad to hear that, Fred. I'm pretty impressed at the comparatively minor cost for what is so substantial a proportion of an instrument that costs $400 USD. My PCB arrived today and I did a quick test to see that it works and yes the muted volume problem is solved. It came quite untuned (pitch field very narrow) so I have to fiddle with the coils which I will do after installing the ESPE01. Then to try and be musical...the hard part for me! 

Quick question if you could be so kind as to explain precisely what type of neon bulb( for each antenna?) I should obtain for the ESD protection, where exactly to solder it and if any adjustment should be required in conjunction with that. It would be much appreciated. 

That's interesting about your finding the EW tough to get a feel for. I concur, but can't imagine how any other instrument would be any different.


Posted: 2/14/2014 11:31:25 PM

From: Eastleigh, Hampshire, U.K. ................................... Fred Mundell. ................................... Electronics Engineer. (Primarily Analogue) .. CV Synths 1974-1980 .. Theremin developer 2007 to present .. soon to be Developing / Trading as . ...................................

Joined: 12/7/2007

Hi Bob,

Standard neons may have too much capacitance - I would go for a part with specified vapacitance like the Bourns 2045 series

I have NOT fitted these to an EW, so cannot say for sure - but I think the extra capacitance should be trimmable away using the variable inductors.(1.5pF will be added by these tubes, so one may need to take some measures to reduce capacitance seen by the antennas - for example reducing the thickness of connecting wires, moving wires away from any ground, perhaps even removing some of the foil.. But I suspect it will be ok without these measures - after all, the antenna inductance was reduced from 40mH to 30mH on recent boards..)

One end of the tube connects directly to the antenna, and the other to ground - a good solid ground lead direct to the power socket is advised. One needed per antenna.. probably safe to go for 90V tubes.


"That's interesting about your finding the EW tough to get a feel for. I concur, but can't imagine how any other instrument would be any different."

Oh, theres a HUGE difference between instruments, IMO - and its not something "simple" like linearity.. I found the easiest instrument I ever played was Lydia Kavina's Tvox (I just love the feel of that instrument), then probably my H1, then the E-Pro in bass register - but I also found some (all?) other theremins (with truly appalling linearity, like the Jaycar and Enkelaar) easier to play than the EWs I tried to play at workshops..

And I dont know what it is - which is one reason I want a real EW board, so I can tune it up the way advised by Thierry, and see if it feels ok to me.. If it doesnt, I can always put it in a box and sell it on ebay ;-)


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