Airport Express wav file vs CD played thru iTunes

I'm streaming wirelessly from iTunes on an iMac G5 through an Airport Express connected by glass toslink to a Benchmark DAC1 and then to my amplifier.

WAV files, which, as Arm said, are uncompressed, Apple Lossless files and AIFF files, which are what you find on CD's, are indistinguishable from each other. MP3 and other compressed formats don't sound as good, though MP3's at the higher bit rates aren't bad.

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.

The difference is jitter. The stock AE has very bad jitter compared to a decent CD player or even a computer playing a CD. A reclocker can bring the performance of the AE beyond that of a good transport or CD player. Most audiophiles that are getting stellar results from Squeezebox, Sonos and AE are using a reclocker after it.

If you dont understand jitter, then read these papers:
http://www.positive-feedback.com/Issue22/nugent.htm
http://www.positive-feedback.com/Issue14/spdif.htm

Steve N.
Empirical Audio

Thanks everyone for the responses.

Steve N, I think you answered my question and the whole issue should be moot once I get an outboard DAC.

Ckoffend, I'm using iTunes for wav file encoding. I had read about others having issues with their encoder so I thought I would put it out there.

Steve,

I guess I am a bit confused. I interpreted from Arm's first post that he was using the laptop with iTunes to play both the CD and the WAV file -which he compared. So wouldn't the AE's jitter apply to both media types, both are reaching the AE as a Apple lossless stream and then decoded there to analog?

Arm, please clarify if I have how you were playing the CD.

ed