Troubel whit pitch antenna.

Posted: 8/17/2019 9:37:37 PM

Joined: 8/17/2019

Hi guys, I recently bought Moog eatherwave theremine.
But I have som troubel geting it to work, after calibration the thermine seems unstable and make a lot of weird noises.
Volum antenna seems to work but the pitch antenna seems not to work and live its own life.
Any good idea what could be wrong?

Posted: 8/18/2019 2:30:22 PM

From: Minnesota USA

Joined: 11/27/2015

Can you describe in more detail what you mean by "weird noises" or better yet upload an audio sample?  Weird noise can occur if you have inadequate grounding for the theremin, but something else could be wrong as well.

For troubleshooting it is best to have a minimal setup to avoid complications due to noise pickup.  First make absolutely sure that the theremin is properly grounded. Next make sure you have the theremin in an electrically quiet area without fluorescent lights, motors, or other sources f RF noise.  Even some LED lights have noisy power supplies that can interfere with the theremin. 

If you have an Etherwave plus with a headphone jack, listen through that instead of using the audio output with an external amplifier.  But if you have the Standard model with only an audio jack, make sure that whatever amplifier that you use is nearby and powered from the same outlet as your theremin.  These are not necessarily things that you will have to do later, but for troubleshooting you need to rule things out one at a time. 

If you still have odd behavior on the pitch side, then an audio sample would help.


Posted: 8/18/2019 11:05:29 PM

Joined: 8/17/2019

The power outlet is grounded as far as I know, and there should not be that much RF noise as far as I know. Tried to turn off all led lights and turn off the modem for the wifi.
No bigg metal objects in the rom, the rom is 4m (13feet) x 7m (23feet) ande thermine is staing on a table whit a stone slab in the middle of the rom.
Tryed to listen trough headphones but I hear the same sounds there to. 
Tried to put it on the edge of the table to see.if the antenna  maybe got muted, but no luck.
Will try to check the continuity of the ground from the socket where I have connected my theremin.

Posted: 8/19/2019 2:26:46 AM

From: Minnesota USA

Joined: 11/27/2015

Since that's a Theremini, not an Etherwave, maybe someone else can help you here.  It doesn't sound healthy...

Posted: 8/19/2019 8:24:34 PM

From: earth

Joined: 5/8/2017

I don't have a theremini so this may not work. 

Do you have a musical instrument cable connected to the theremin? It should be long enough to lay 6 feet or so on the floor or ground and then connect it to a music amplifier.

This provides grounding, helpful if you put some of your meat in contact with the cable. ( I use a foot with a sock on it. my own, currently attached.)

I did not notice a music instrument cable attached to your instrument and assume you are using headphones to provide amplification which do not provide grounding which a real theremin needs.

You can plug your headphones into the amplifier or mixer where the theremin is plugged into.

If this doesn't help, buy a real theremin, the easy one is the model 302, but no one wants an easy theremin.

After a real theremin proves too frustrating, buy the easy one with the plate antennas.

Posted: 8/20/2019 1:33:13 AM

From: The East of the Netherlands

Joined: 6/18/2019

Hi Legotass,
There seems to be hardly any sound in the video you posted, just the annoying 'digital warble noise' that is caused by the EMI noise of the switching power adapter.

After getting my 1st theremini exchanged because of this warble background noise, the next one was sent back to the importer who after keeping it for about 2 months could find nothing wrong, then after finally pinpointing it to the adapter myself, got the power adapter exchanged, which again didn't help, and in the mean time I had gotten a regular 12V keyboard power adapter, which doesn't provide the grounding connection, but I was playing it over an amplifier that provided grounding anyway, and for the rare occasions I would use it without a grounded amplifier I made a cord with just the safety ground connection to the plug which I can connect to the ground screw on the back of the theremini. For the actual sound you might want to check if the master volume in the setup isn't on 0 or very low value, and for the internal speaker/headphone, that the volume knob is turned up.

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