A nice PC upgrade

Has anyone noticed any differences in sound quality using an external HD, as opposed to using internal SATA drives?

Zd,

I have not tried it myself, but several people at other fora tried it time ago and it is a sort of an accepted fact they do sound different, with the SATA sounding "better" because it doesn't introduce additional jitter on the USB bus. This is assuming the DAC in use is asynch USB.

USB stands for universal serial bus, so all processes run in series. So when streaming audio data to the DAC and retrieving data from the HDD those processes are in series. Data retrieval has no timing aspect related, but it seems to add some jitter that affects the audio data stream going to the DAC, and sound quality appears to be affected that way. At least this is the way I've come to explain it to myself :-)

I used to run a laptop with a USB drive and asynch USB DAC and it worked fine. Then moved to a CAPS like server which sounds much better, but honestly many things changed from one server to the next and I have been to lazy to try connecting a USB drive to the CAPS and check it out. I should do it, but it's a little cumbersome because my CAPS runs headless.

USB stands for universal serial bus, so all processes run in series.

A clarification: "Serial" in the context of a data bus such as USB doesn't refer to processes. It refers to the fact that the bits are transmitted through the USB interface one after another, on the same wire. Or more precisely, on each of two wires, since USB utilizes a balanced pair of signals, which are the same except that the polarity of one is inverted relative to the other.

The opposite of a serial bus would be a parallel bus, in which (to cite a hypothetical example) the 16 or 24 bits of audio data (per sample per channel) would be transmitted simultaneously on 16 or 24 parallel wires (or balanced pairs of wires). That is not done for reasons of practicality, cost, etc., given that serial bus technology is available with sufficient speed to communicate the bits one after another.

That said, it is certainly conceivable that the amount of noise and jitter on the USB interface to a DAC could be affected to some degree by the type of drive and drive interface that is being used.

Best regards,
-- Al

Thanks guys. I have seen the marantz and bryston. I think if I make a change, will custom build with linear power supplies or just buy a baetis. Thanks.

Thanks Al. Very pointed, clear and helpful explanation. As usual!