Herman - The key is to make some sorting. Most of items you mentioned are in analog domain where things are getting extremely complicated but "bits are bits" is relatively easy to explain. Data stored on HD is retrieved without error - (not even single bit) or computers would not work. Data is extracted first to HD cache buffers and then to computer memory to end-up in FIFO output buffers. Data leaves FIFO buffer bit by bit exactly same (no matter what drive it came from). Digital data can only sound different if jitter is involved (noise in time domain). It doesn't apply here since transmission between HD and computer is synchronous (clocked). Computer has to present on its output exactly same information from the same file on different HD otherwise networks would not operate properly.
Asynchronous S/Pdif data coming from CDP could be an example of place where bit are not just a bits because of jitter.
It is remotely possible that you might hear different sound from different HD because of ground loops created by disk that affects analog audio - but it has nothing to do with type of HD. That would be pretty good example of case where experiment is useless (brings false conclusion).
People claim that jitter rejecting Benchmark DAC1 is still sensitive to transports therefore not exactly jitter rejecting. Strange part is that cheap DVD players often sound better with DAC1 (according to their testimony) than expensive transports. How is it possible? Again - wrong conclusion. Jitter rejection of Benchmark DAC1 has nothing to do with it and it is simply ability of given player to retrieve data from CD (DVD players have good tracking). It could be issue of ground loops as well.
Negative feedback that you mentioned indeed lowers distortion and sounds better but only if is used intelligently. Good designer would design amp as linear as possible to get below about 5% THD and then apply negative feedback to knock down THD to about 0.5%. Now it becomes necessary to lower input bandwidth to one that amp had before feedback was applied (to prevent TIM distortions) and voila - we got great sounding amp that nobody will buy because it has limited bandwidth and 0.5% of THD.
Asynchronous S/Pdif data coming from CDP could be an example of place where bit are not just a bits because of jitter.
It is remotely possible that you might hear different sound from different HD because of ground loops created by disk that affects analog audio - but it has nothing to do with type of HD. That would be pretty good example of case where experiment is useless (brings false conclusion).
People claim that jitter rejecting Benchmark DAC1 is still sensitive to transports therefore not exactly jitter rejecting. Strange part is that cheap DVD players often sound better with DAC1 (according to their testimony) than expensive transports. How is it possible? Again - wrong conclusion. Jitter rejection of Benchmark DAC1 has nothing to do with it and it is simply ability of given player to retrieve data from CD (DVD players have good tracking). It could be issue of ground loops as well.
Negative feedback that you mentioned indeed lowers distortion and sounds better but only if is used intelligently. Good designer would design amp as linear as possible to get below about 5% THD and then apply negative feedback to knock down THD to about 0.5%. Now it becomes necessary to lower input bandwidth to one that amp had before feedback was applied (to prevent TIM distortions) and voila - we got great sounding amp that nobody will buy because it has limited bandwidth and 0.5% of THD.