I’m curious, how many people are aware of these sounds. I have designed, etched, and built my own switching power supplies along with winding my own transformers. I am aware of the source of the noise. So, does anyone else hear these high frequency sounds regularly?
Yes, often, especially lower quality ones.
You might want to ask this question versus age. Our ability to hear higher frequencies drops with age. They even make high frequency ring tones that teens can hear but their parents can’t.
I remember when I was little I used to hate my grandma’s old tv because there was always a high pitched noise that came from it when it was turned on or off, my grandma was never able to hear it though and I couldn’t understand why till I learned about how we struggle to hear higher frequencies as we age.