Bought an etherwave theremin last autumn, built it and played it for a couple of months, then I didn’t have time to play for about half a year. When I tried it again both pitch and volume seem severely out of tune, pitch cannot be nulled, nulls when hand is 2-4 inches from the antenna depending on knob setting (should be able to null when no hand near antenna), and no matter what volume setting, volume increates to a max 4 inches from antenna and then fades out (volume should not increase before fading). Could be a tuning problem, but since the circuits are separate, it’s a bit odd that they’ve both developed severe problems at the same time, while in storage, could it be any other common problem? Any clue? Have tried to relocate the instrument to different locations, but the problem persist.
Hmm, even more strange, just tried the theremin again (after a couple of weeks), and now it seem to work again, maybe the volume circuit could need some adjustment. Magnetic trolls in the house last time I tried? If not I can’t figure out what the problem was, the same setup (amp, cable, mains socket) and location (one of them) as when it didn’t work.
Could be, but what’s a bit odd is that it severely affected both pitch and volume circuits, and I can’t see much common between these, except power supply and when they merge in the IC, and the latter can hardly affect both tuned circuits, so it may be a power supply problem. I’ll check…