Yeah, my laptop also has the dual SPDIF/headphone jack. If your just using a miniplug RCA cable you're using the headphone functionality. You'd need a digital cable with a mini-plug end or adapter to get the full digital stream.

So the fact that SPDIF sounds different than the headphone output is a figment of my imagination? I'll need to A/B when I have some time.

It might not be your imagination. Some players re-sample systematically to 48K for SPDIF output while playing native 44.1 on their analog circuits (Soundbridge M1001 is a good example of such a difference).

But he's not using SPDIF if he's plugging the Audiobytes into that dual jack; he's using, essentially, a headphone jack.

It does not mean it is the same output than the single-usage headphone jack.

Why not? Why would a manufacturer put a separate audio processor in for outputs that are essentially doing the same thing? Sure, the traces are going to be a little different, but do you think that there's going to be that much variation in the sound (audibly) from a few millimeters of copper?

It might not be coming out of the same chip.

So they've put 2 sound chips on the board.

This is just speculation (on BOTH sides). Two outputs serving two purposes can very well have two separate chips. The Soundbrige mentionned earlier is a perfect exemple of that.

Since, again, we are all speculating here, let's try to keep this friendly and avoid putting words into posts!

Oh fine... as usual, I should be a little more careful with my posting in the morning. Sorry about that.

However, from my knowledge of system architecture in computers, I would wager that the outputs are both from the same chip, unless there is sound processing on the south bridge (rare, possibly nonexistent) or has an "add-on" chip/card on the board (such as an X-Fi) in addition to the typical Realtek chip. '

This post is an invitation for someone to come along and tell me I know jack-all about system architecture.