Airport Express wav file vs CD played thru iTunes

The one thing you have indicated that could be involved with the sound quality is when you indicate:

"is the wav file encoder for iTunes the issue?"

My question to this is are you ripping your CD to your computer using a WAV lossless file then importing this file into iTunes? While I am no expert on iTunes (don't much care for it personally), I thought when a file was converted and brought into iTunes it became an MP4 (which is compressed).

Perhaps I am off base on this, but I would check and confirm that you are bringing the lossless WAV file into iTunes (if there is any conversion, which I thought there was) using an Applelossless codec versus the standard MP4.

Also, I suspect that the internal DAC is part of the issue, but it sounds like you are already planning on doing something about this.

Eric - there are several anti-jitter units available, both old and new. The older ones were made by Audio Alchemy and also Genesis' digital lens (I believe did this). There are some modern day DACs that also incorporate jitter reduction and other DACs that depending on the transport can act as the main clock for the cd transport/player and of course there are also external clocks (such as the two by Esoteric). But for either a DAC or an External clock to work, one must have the appropriate connections and capabilities for them to connect to the transport/CDP. As a result, in some cases, you are getting into pretty big bucks with the clocking approaches.

From what Audioengr stated above, the AE has a tendency to create a lot of jitter. Perhaps there are alternative devices to the AE that may fix your problem more to your satisfaction - perhaps others that are more familiar with some such devices could recommend them here? Are you using the AE for wireless purposes?