I have my music CDs downloaded in the Apple lossless format, have got a new (gen2) Airport Express at my HiFi. First I used the analogue output on to my amplifier, but yesterday I switched to the digital output and a brand new Rega D/A Converter. Needs some time to rum-in, but I discovered that switching off the "sound improvement" in iTunes settings actually improved the sound. (danish version, might be called something else in english) Still I have some noise like pulses appearing now and then, did not have it before.