If you have a "kick booty" DAC, does the transport

After a lot of tests and money thrown away I can tell you..
the most important part of a digital playback is the Transport...the most expensive also.
Yes it seems logical that a computer HD would read better, try it out and try a "real" good dedicated transport in your system, you wont believe the difference!
Forget about DVD payers with cheap plastic transports and switching power supplies...aargh,

Thank you Gliderguider for that nice explanation, that clears up a lot of things...

Kthomas,

Much (most?) of the problem is that the SPDIF interface doesn't carry timing information, certainly not bit-level timing info. The time base has to be recovered from the signal, and that is inherently problematic on a high frequency link. This is why digital cable quality is so much more important that you'd think it ought to be. It's also why quasi-proprietary interfaces like IIS were developed, and why there is curently so much interest in USB - they pass explicit timing information as well as the data, and so should minimize this particular problem.

Kthomas,

One further note - the reason you don't have this problem in a computer is because of the "system clock". This high frequency clock signal is fed to all parts of the system, and synchronizes all data transfers, even between boards, at the bit level.

In a system like the standard CD transport/DAC, each box has its own clock and the two are not synchronized. This is a theoretical argument in favour of one-box players. Of course it only addresses one issue (timing), and there are plenty of other ways to muck up a high-frequency signal.

A DAC that doesn't separate itself from the player with its own clocking must rely upon a very expensive player and a very expensive digital cable for the timing and delivery of the bits. That is, for the feeding of the bits to the digital converter chip.

Some modern DACs, in different ways--some more successful than others, have overcome this problem by reclocking the data making it possible to use a wide variety of relatively inexpensive players, including those that play SACDs and DVDs as well as CDs. They can do this with no sacrifice of audio quality on that account.

Of course how they handle the analog signal delivered from the converter chip will always have an effect on the sound.

Cable Quality?... SC Pulse transformers, and cat5 cable will blow many highend digitals out the water! USB has issues too.