[webstrand]

Class D amplifiers use that same trick, just at much higher switching frequencies (pushing quantization noise ultrasonic, where it can be filtered). Since transistors are most efficient when fully on/off, very little power is wasted as heat. That's what made the modern revolution in tiny amps possible.

[bob1029]

It's pretty amazing what you can get in terms of power density these days.

https://www.amazon.com/Digital-Power-Amplifier-IRS2092S-Chan...