was there any solution to this problem? I'm running a few samples from a SD card out of the DAC of a Teensy 3.2 (no audio adaptor), and I can hear this 344 Hz buzz only when the samples are playing.
To me, this does not seem like a ground loop issue
so if power supply sag is a problem, what's the best way to fix it? looking through the forums, the teensy cant natively be powered through its 3v3 pin, so im not really sure what would be a good way to do it. even powering it by a portable battery pack that can charge a phone relatively fast still gives the whine. maybe a CV/CC power supply would work for this situation?My experience was that indeed the SD card accesses were causing power supply sag
And playing 7 audio files is fairly easy, if you try my improved library: discussion and links to the repository in https://forum.pjrc.com/threads/70963-Yet-Another-File-Player-(and-recorder)