Most modern power supplies are switch mode they are in everything. They are noisy. All you need is an analog power amp (tube) hooked up to some speakers, hum like a mofo. All is required is a X Capacitor across the line.
Can do that for both the switch mode supply to keep from generating noise and one for whatever device you don't want to hear noise with.
X Capacitor = across the line Capacitor.
Can do that for both the switch mode supply to keep from generating noise and one for whatever device you don't want to hear noise with.
X Capacitor = across the line Capacitor.