WiiM makes two types of network streamers: powered and unpowered. A powered streamer (a.k.a. “Network Amplifier”) like the WiiM Amp or WiiM Amp Pro includes a built-in stereo amplifier. This means it ...

The WiiM Ultra doesn’t include an amplifier with speaker outputs, ... The other feature missing for me is a USB input either for attaching a hard drive of music or for streaming from a computer.