"I guess If you destroy the original signal (say in a bad computer or a crappy DVD player) and then reconstruct it on the DAC, the result is not the same as if the signal is kept complete (as much as possible) from transport to DAC. "
How are you destroying the signal ? The digital signal is nothing more than 1s, 0s and timing information. I'll bet that even the crappiest DVD player's digital output has 1s and 0s that EXACTLY match even the most expensive transport. The $20 DVD-ROM drive in my PC seems able to extract and install windows XP without a single bit error, and it can do this while reading the CD many times faster than an audio CD has to be read.
A computer is quite evidently capable of preserving the 1s and 0s, since it's able to install an operating system from a CD-ROM. The computer might have jitter and noise on the output, but it's not rocket science to buffer and reclock data, to completely remove the timing jitter from the computer.
How are you destroying the signal ? The digital signal is nothing more than 1s, 0s and timing information. I'll bet that even the crappiest DVD player's digital output has 1s and 0s that EXACTLY match even the most expensive transport. The $20 DVD-ROM drive in my PC seems able to extract and install windows XP without a single bit error, and it can do this while reading the CD many times faster than an audio CD has to be read.
A computer is quite evidently capable of preserving the 1s and 0s, since it's able to install an operating system from a CD-ROM. The computer might have jitter and noise on the output, but it's not rocket science to buffer and reclock data, to completely remove the timing jitter from the computer.