< Sounds like jealousy to me
I've seen $200+ plastic, I mean polymer cables, and $35 glass ones. I went from a decent quality plastic fiber toslink cable to a similarly-priced glass one, and I noticed a difference. But that was with my highest-quality DAC, the NOS Bel Canto DAC2, which has its own master clock that is optimized for s/pdif: "A local crystal oscillator reference clock drives the DAC directly for minimal jitter."
Where I found the Firestone Bravo re-clocker to make a profound difference when used with my balanced Mini-i DAC, on the Bel Canto it had no effect. But what did have a notable effect was switching to the glass cable, that really tightened things up with the BC. So I tried the glass cable with the Mini-i, and it did not make a difference when compared to the cheaper plastic one.
The difference in the two results, I believe is the superior "local crystal oscillator reference clock" in the Bel Canto, making it sensitive enough to resolve a difference in the heightened transmission quality of the glass. I've never tried a high-dollar "advanced polymer" toslink cable though, they are likely very nice as well and probably more durable.
Another difference would be that the Mini-i just sounds better when using its coaxial input, rather than its toslink or USB input. So the Bravo is fully utilized with it, providing a re-clocking function along with an s/pdif coaxial converter. The Bel Canto sounded equally good with coaxial and toslink, but better with the glass toslink.
These results are all highly system-interdependent; a tweak that improves one component won't automatically have the same result on another one. We have to look at the DAC conversion as a collection of processes to discover where the deficiency may lie.
Like Robsix said, the Tx/Rx modules are part of the story as well, just like every other link in the digital-analog conversion chain; they all matter in regards to the final product, the sound that hits our ears.
Edited by grokit - 3/9/11 at 11:17pm