That makes sense, I have just experimented with a new method;
I have ditched the airport express as the stuttering was problematic and downloaded a piece of software to allow my MacBook to act as an airplay receiver.
Now when using my MacBook the output is direct optical to Phantom but I can also use my iDevices and other Macs in the house to stream to the Phantom by airplay though my Macbook (which has a more consistent output than the AirPort for some reason).
I have ditched the airport express as the stuttering was problematic and downloaded a piece of software to allow my MacBook to act as an airplay receiver.
Now when using my MacBook the output is direct optical to Phantom but I can also use my iDevices and other Macs in the house to stream to the Phantom by airplay though my Macbook (which has a more consistent output than the AirPort for some reason).