Seasonal tuning changes

Hey all!

My Etherwave has gone so badly out of tune, I can't play it.

That is, I can't get a playable range even with the "Pitch" knob turned all the way clockwise.

Does anyone else's do this?  Is it related to humidity?  Humidity in my area ranges from zero in the wintertime, to 100% this time of year.

Is there any way around it short of taking the cover off and adjusting the inductors?

Daniel,

At some point you must learn how to tune your theremin. It gets posted here by me and others once in a while.

Make sure you have a good earth-ground, more important than many realize.

There are two methods of re-tuning by not taking the cover off.

#1 - Send it to Thierry as the only one I trust in theremin repairs.

#2 - Use a gimmick wire like seen in the picture. This only works in one direction so you may get lucky. It is 50/50 that it will get better or worse. Dangle an eight inch looped wire at the base. Add or Trim to meet your need if it works.

Christopher

Oh, I just did it.  Set L5 to 3800Hz, fuss with L6 to get zero beat at 10cm, put the cover on, fuss with the cover on and off until I get zero beat at 60cm.

I was just wondering if anyone else's went out of tune like this too.

OMG - Set L5 to 3800Hz, fuss with L6 to get zero beat at 10cm, put the cover on, fuss with the cover on and off until I get zero beat at 60cm.

Never touch L5 unless you have a scope, you will mess up pitch field linearity if not tuned to just above the antenna circuit.

What ever you have done will seem to work but how good?

I have seen that approach you used before and I bet dewster would even frown upon it, to a theremin designer it makes little sense. That is like removing lawn mushrooms with an axe.

Edit: Pitch Field Linearity has nothing to do with heterodyning or zero beat or even direct earth ground. It is a unique tuning phenomenon.
That wire gimmick also put there to make up for when the cover is off.

Good Luck

Christopher

Yar I have a spectrum analyzer app on my phone, it's fine to set L5 to 3800. I have Thierry's ESPE01 or whatever it is so I have very good linearity.  It's all good, the instrument is playing great, my range is exactly where I want it.

Daniel where did you find this "Set L5 to 3800Hz, fuss with L6 to get zero beat at 10cm, put the cover on, fuss with the cover on and off until I get zero beat at 60cm."

Let me explain my position so others understand, the 3800 Hz audio frequency is only relative to the setting of L6 hoping it is set correct but it could be way off. It has nothing to do with antenna linearity tuning. I am sure most people adapt to their own pitch field linearity. 

One day all Pitch Fields will be ideally similar, I figure linearity is why so many gravitate towards the E-pro. They like Pros "not" for the stock volume response but it does have a slightly better whistle than a stock EWS.  Once someone experiences the E-pro Ideal Pitch Field Linearity they never want to give up the comfort and precision in playing.  A properly tuned EtherWave Standard can have quite good linearity. Grabbing the end of the pitch antenna is not going to get you there.

Christopher