Thermemini: Strange oscillating background noise through speaker

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FiercelyFuzzy
Posts: 2
Joined: Wed Jan 05, 2022 12:55 pm

Thermemini: Strange oscillating background noise through speaker

Post by FiercelyFuzzy » Wed Jan 05, 2022 1:02 pm

Hi Everyone
I am having trouble with a strange background noise coming from my Theremini.
There is strange oscillating sound in the background all the time.
But this sound is only present when I use the internal speaker or connect it to an external amplifier/speaker. I cannot hear it through the headphones. Also, I can hear it through the internal speaker when the volume is at zero.

Here is a link to a youtube video I made of the sound when heard through an external amplifier:
https://youtube.com/shorts/7xNA9bctNX0?feature=share

I calibrate before each use and have tried the theremin in different rooms of my house so I don't think it is an interference or ground issue (if it was, why do I not hear it through my headphones?).

Many thanks for your help
Best regards
Paul

Chanctonbury
Posts: 5
Joined: Sun Feb 17, 2019 1:23 pm

Re: Thermemini: Strange oscillating background noise through speaker

Post by Chanctonbury » Wed Jun 08, 2022 3:54 pm

Hi Paul,

You are not alone, I have exactly the same issue including the clean line and headphone outputs. I have tried different rooms, different ring circuits, using the ground post etc. all to no avail.

Just realised, Paul, you and I have already discussed this issue elsewhere but it doesn't harm to log it here!

Regards,
Steve
Kind regards,

Steve

ade500
Posts: 1
Joined: Wed Jun 22, 2022 3:37 am

Re: Thermemini: Strange oscillating background noise through speaker

Post by ade500 » Wed Jun 22, 2022 3:41 am

Hi guys

I had this exact problem - just the same as the YouTube clip. I changed the power supply. Somehow I had got it swapped with my Yamaha keyboard supply.

With the original power supply the Theremini works fine.

Ade

FiercelyFuzzy
Posts: 2
Joined: Wed Jan 05, 2022 12:55 pm

Re: Thermemini: Strange oscillating background noise through speaker

Post by FiercelyFuzzy » Sun Jun 26, 2022 11:52 am

Thanks for the advice Ade!
I'll try a different power supply.
Cheer
Paul

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