Teensy 4.1 + Audioshield rev D2 mic input random noise

miata

New member
Hello!

I have successfully built my own audio guestbook based on the https://github.com/playfultechnology/audio-guestbook repo.


I want to make a second one but I encountered a strange thing (Teensy 4.1 + Audio Shield rev D2)

I noticed that if I have the teensy on for a few hours, random noises are added to the recording. I attach one of these.
View attachment 00004.wav.zip

In the previous build I used rev D audio shield, no such error occurred there.

I will also show a picture of the soldering. I'm really annoyed by this. Even when the microphone is not connected, this noise is still present. Could I have damaged the audio shield? Is it significant that I connected the speaker to the line out and not the 3.5mm output?
IMG-3188.jpg
IMG-3189.jpgIMG-3191.jpg

Thank you very much for your help!
 
The line outputs are line level and cannot drive any form of speaker (which requires high current). This would stress the SGTL5000 well beyond its ratings. Typically a line-level output is expected to drive impedances in the 10k to 100k ohms range.
 
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