Op amps. Often the first thing that many learn ... though it does give this particular model the ability to output 100V pk-pk without any distortion.

WiiM now sells the Vibelink Amplifier, its first standalone amp. It doesn't offer any Wi-Fi streaming or Bluetooth ...

Looking at the circuit diagram it follows the classic op-amp with a long-tailed pair of NPN transistors driving a PNP gain stage and finally a complimentary emitter follower as an output buffer.