What could I expect in terms of improvement, by adding a DAC to a Denon CEOL? I'm looking to be able to stream music via Bluetooth from my Android device? Any tips in terms of what model of DAC to go for?
You could plug in something like the little Arcam rBlink into an aux analog input on the back of your CEOL.
It is very expensive (£159) for what it does, but has had good reviews.
Personally, I don't know why you'd buy an AirPlay system for a Bluetooth device. Should plan these things and get a system with Bluetooth built-in in the first place.