Digital Cable Choice; how critical is it?

Nsgarch - fair question, but my better angel is telling me to just give up, take my toys and go home. If anybody is interested and has a fairly fast internet connection an insight into what is possible to take audiophile concerns (ac line effect, vibration tweaks, digital & power cables, why does my system sound different than it used to, etc.) more toward science is at http://www.dataq.com/applicat/presentation/I_A_hardware-overview.html
Happy listening!

Jeff, thanks for the link. I enjoyed the presentation.

Have you used this device to measure the things you mentioned in your audio system, or it it strictly a work tool?

I've never used anything but AT&T glass. For one thing, the Wadia DAC I used to have just had one glass input! (My new one has several different kinds.) I did try a lot of different AT&T cables though without any impressive differences UNTIL I sprung for an Aural Symphonics Optimism V2 and WOW! What an ear opening experience that was, with slightly different tonal balance depending on which way the cable was oriented. I know, according to your measurements, that should have no effect -- and it didn't with all my other ST cables.

As for 75ohm jobbies, all I know is what I've heard about connectors -- that BNC connections maintain the 75ohm continuity better than RCA connectors and therefore provide a more accurate datastream to the chips. But I don't use metal, so I haven't ever compared.
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Nsgarch, I'm only referring to 75-ohm metal cables, I have no experience with any other kind.

My experiences have shown that there are dramatic sonic differences between digital cables. I cannot explain these differences in scientific terms but I am sure they exist, zeros and ones notwithstanding. One thing of which I'm sure, the differences are not "placebo" effect. Does everything that can't be explained by science fail to exist?

Nsgarch - Just work to date for a recording device. The one o these days plan is to get the meaningful measurables on my audio system recorded to hard disc for reference and troubleshooting, and then too start digging into things like does the dc buss on my pre amp wiggle when the fridge kicks on & does this create a measurable difference to a constant frequency wave output measured between amp & speakers.