Libratone Zipp is equipped with an analog 3.5" AUX minijack input which allows for a wired connection.

Use the "Headset Out" connector and connect a shielded minijack-to-minijack cable to AUX audio input on your Zipp. 

If you start streaming AirPlay to your Zipp the sound source will automatically switch from cable to AirPlay streaming, as AirPlay is prioritized.