Gerrardasnails:Dan Turner:
Theoretically you can get a bit perfect output from a CD transport and this would present identical information to the DAC, compared to the file (assuming a bit-perfect rip in the first place) played back from a HDD.
The difference is that a music CD being replayed is read in real-time, meaning that the transport has only one chance to get it right, or on-the-fly error correction has to make an educated guess at what bits should be present when there is a gap. Any dust, scratches, moisture or microscopic wobbling of the disc as it's spun can result in less than a perfect read of the disc.
HDD replay does not occur in real-time, the HDD can re-read the information as many times as it needs to, and in any case is not susceptible to any of the above.
Ripping a CD or reading a data CD is susceptible to all the problems normally associated with reading a music CD, but critically like the HDD replay it doesn't happen in real-time and the disc can be re-read as many times as necessary in order to get the right result (or as close to it as the condition of the disc will allow).
Replaying music from a HDD requires plenty of other hardware besides the HDD itself however whilst the 'data' is being handled by computer protocols then it is just data and is not subject to degradation - e.g. as it's shunted from one point to another either within a computer or across your network/the internet then there are checks in place which ensure that everything sent is received. If there is a problem with this reconciliation then the offending data 'packet' is simply resent, as the whole process is not time-critical.
The moment the data is turned into a clocked PCM signal then (this is my opinion here - other people may disagree) it becomes a musical signal and is subject to degradation by interference or the introduction of jitter, (and there are no any longer checks in place when sending/receiving). In a CD player the data exists in this state from start to finish, whereas in a computer-based solution it's not until the soundcard or other hardware output device renders it as a PCM signal - so much further downstream.
So - it's more a question of reliability and susceptibility to degradation than of one being inherently better than the other.
I couldn't have written that but I agree! This is why a lossless file into a DAC sounds better than the cd transported to the DAC via a cdp.
A lossless file sounds worse than a CD through the same DAC, in my experience.