I can't tell the difference

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

Thanks Al, I look forward to the reading.

Mustard, let me unload a well known message here: break in, break in. How much time did you grant the V-dac before critical listening? I know it's hard to grasp how long fine dacs (no moving parts, only kind of electronic alchemy) need to come to themselves.
I did't hear the V-dac and have not read owner's reports concerning its break in characteristics, but, given how unresolving and unengaging the SB3 dac sounds, I would be surprised if a well burned in V-dac didn't lastly lift sonics quite a bit here.
When new, even seemingly simple units like the Valab dac need a week of constant converting work, after which it likely outperforms Lavry DA10 or the Transporter dac, as my ears were inclined to tell me.. As does, to a still higher degree, the new Wadia 151 in my system - and similarly, only after a week of having run continuously.
Well, all this burn-in talk might be old hat to you! Sorry in that case. I just wonder how many machines are being judged, sent back or reported on ahead of due time.

The V-DAC has about 40-50 hours on it. I have another couple weeks or so before I have to make a final decision on it, so I can give it a little while longer and do another blind test. My speakers are also very new so they may open up some also. I'm more willing to accept that the speakers will benefit from more time than I am the DAC, but I'll let my ears do the talking.

I'm pretty new around here so I'll try and keep an open mind. That said I'd like wade through the hifi voodoo at the same time. I'm also willing to accept that my system might not be revealing enough for me to pick up on certain things. I don't have the experience to know at this point.

Thanks for all the input.