Dare I put my toes into the water? I'm a physicist and audiophile (establish credibility!). I've been into living room system audiophilia for 20 years. This pc-audio is new to me and I'm just starting up. Now, about USB cables: I can hear a small difference between cables. If we assume the bits are transferred properly (and there is some debate about that in USB-audio vs. USB-data), I think the issue is electromagnetic nosie getting through the circuits and into, in my case, the headphone amplier. All EM noise is immediately spread through an entire system, end-to end. Since at the end of the day, something is converted to analog to hear it, the cleaner the power and the better the shielding, the cleaner the final D/A will be. This will not be anything that affects data transfer, per se. All billion TB of information can be transferred with perfect fidelity; when you open your word document, all the correct words are there. But we don't listen to data files. There has to be analog conversion somewhere. In my living room system, it was always well worth the effort to clean up the power and have well shielded cables. Do any of the audiophile USB cables actually provide effective power filtering and shielding, such that the headphone amp is cleaner even though connected to the PC? I don't know. This can be properly done in a living room system. But there are snake-oil produccts there too, of course.
