I bought the "Power supply 5V/2A EU plug" on Hifiberry web site.
RaspberryPi and DAC + PRo word well, but the power supply plug is noisy.I hear a whistling sound when it is plugged.
I used an app on my phone to analysed this sound (Advanced Spectrum Analyser PRO), when I put my phone near the power plug, an high frequency sound is visible. You can see the screenshot.
Is this whistling is normal ?