Vinny7:From what I have read, it seems that the Airport express is just a wireless way to transmit the sound from your PC to your Hifi - usint iTunes?
Now does adding the Cambridge Audio DAC create a better sound or is it not needed?
Yup, that's exactly it - you still want the DAC for a better sound as the one built into the AE unit is good considering the price, but the DacMagic will definitely improve it.
As for the best sound, I think USB or digital coaxial are considered the better methods than optical because there is no conversion of the electrical signal (optical converts it to light), but I don't think there's a lot in it personally.
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