It seems that the instrument is internally completely out of tune and/or that one of the volume coils is partially broken (happens sometimes after shipping). This may give these ghost tone and locking effects when you touch the volume loop.
If you paid more than $250 for it, return it.
If you paid less it is worth being shipped to me for reparation and upgrade at the same time.
I experienced the exact same thing when I took my Etherwave to Denmark to premiere a new piece this week. I can usually make this fault go away by turning the volume knob fully counterclockwise and retuning it while touching the pitch rod. Can this problem also be caused by insufficient grounding or is it always a symptom of bad internal tuning or defective volume coil(s)?
At distance, I can only use my experience and some statistics. But I can't do a thorough diagnosing. Bad grounding may make worse any existing problem.
If you see often the need to retune the instrument, grounded or not, there is definitively something wrong and you should try to find out the cause instead of repeatedly curing only the symptoms.
The partially broken 5mH coil is a common source for such problems, another is sometimes a partially defective diode D1 (which may look fine with the multimeter but the oscilloscope will show a breakdown at ~20V in reverse direction). In rare cases I have also seen ghost tones coming from the circuitry around the volume tuning stage (Q8 and friends) which started sometimes oscillating itself and which gave an unwanted amplitude modulation of the audio signal.
I know that Thereminists are often in a difficult situation. There are only a few competent service points around the world and money is also often an issue. But in some way you should see your instrument like a car which needs to be serviced in fixed time intervals or after a number of kilometers or miles...
BTW: I plan to improve the general situation starting next year and to offer weekend classes for people who want to learn how to service and fix theremins (semi-) professionally.
So I have a question here regarding pots and what nots.
I was wondering if I can change my pots out with precision pots so that they are not so sensitive.
What do you think? Seems like it makes sense and would be fairly easy to do. Have you ever tried this or know anyone that has?
Thanks. Love the bass module.
I want to take a class! I am in Ca. though. Mind having a roommate for a few? I should just go over there and do a synth tour. I've been getting into the modular world as well. Mainly research so far. Got any tips in that arena?