Pretty true. Most electrical thingies emit some sort of acoustic noise, especially amplified by speakers. Don't worry about it. Enjoy the music
Slight hum coming from preamp/amp
I got a Nakamichi CA-5/PA-5 that I connected to a laptop via an external DAC. When I set it up and turned on the amps, I can hear a slight hum coming from the speakers. It can only be heard if you press your ear against the speaker. I looked up the issues online and tried to isolate the noise by just connecting the speakers to the power amp, and the hum noise reduced down significantly but I can still hear it if I press my ears next to the speakers. What should I do next?