I can't tell the difference

@jult52, I suppose the comparison to tcp isn't too valid as spdif won't be a two-way handshake. However, I'm still skeptical. In order for there to be a transmission error in the digital domain, the physical medium must be modified beyond a given threshold (voltage level or light measurement?) to have any impact. Yes it's technically possible, but if it's happening with any regularity I imagine the results would be painfully obvious, in which case you'd deem the cable defective. Using an optical cable would avoid the potential for surrounding electronics to impact the transmission, but based on error rates I've read in passing this likely does not matter either.

mustard...you are going to get yourself in trouble trying to apply logic to all of this! the "believe your ears" thing you have going with the blind tests is really the only way to evaluate this effectively. spdif cables will sound dramatically different, whether they should or not i don't know but they will. i actually would say that a digital cable can be the most influential cable in a system. i took great care in selecting mine and it has paid off nicely. i am graced with ignorance so i have little choice but to just give this stuff a listen.

@Richard_stacy -- I agree our ears are the end-all-be-all. However, the laws of physics cannot be evaded. There has to be some logic to where we look for differences, no?

Have you done any blind tests with your digital interconnects? I'm very open to the possibility that I'm wrong here, but I'm one of those people that needs to understand why something works... maybe I'm in the wrong hobby :)

you know, i do understand that but i have just come across so many weird things after messing around with this stuff for years. i'm sure there are reasons for why digital cables sound different i am just not able to understand yet alone explain the bulk of it. no, i have not done blind tests but i have a very revealing system and can assure you these differences are not subtle. my digital cable is hands down one of the biggest contributors to the level my system is operating at these days. if you only knew how my power conditioner worked...you would really think i was nuts!

could you point me to some documentation that describes how a cable could impact the spdif transmission?

You'll find this article to be of interest. It explains how cable LENGTH can be significant for spdif transmission, by affecting jitter:

http://www.positive-feedback.com/Issue14/spdif.htm

Of course the degree of significance of the effect he describes will be dependent on many variables, that will be different from system to system. Those include the jitter rejection capabilities of the dac, if any; the risetime and falltime of the transport output signal; the degree of impedance mismatch between cable, connector, transport output circuit, and dac input circuit; the exact logic threshold of the receiver device in the dac input circuit; the data rate that is being transmitted; the amount of electrical noise that is present, etc. etc.

For a given cable length, different cable types will affect the degree to which some of those variables come into play, particularly impedance matching and noise pickup, both of which will in turn affect jitter.

Regards,
-- Al