I was just browsing around the forum, reading various threads and I ran across a post where someone mentioned the huge upgrade in sound that an upgraded USB cable brought their DAC. Then another person chimed in talking about how great the USB upgrade was. They were talking about increased sound stage, "musicality", "tonality", and all the usual stuff I hear mentioned with regards to sound quality. The only problem is, it's physically impossible for an upgraded USB cable to provide those things. USB is digital. The data going from the computer to the DAC is 1s and 0s. It either gets there or it doesn't. I.e. music either plays or it doesn't. It's not analog, so the cable simply can't affect the sound that way as there is no actual sound traveling through the cable, just data that gets decoded by the DAC. It's just like saying a $100 HDMI cable makes the picture on your HDTV really "sparkle" and really "brings the colors out". It's just physically impossible. Now it's possible that a well shielded USB cable could improve sound quality over a cheapo cable by reducing outside interference, but they weren't talking about lowered hiss or interference sound. And this wasn't the first thread I've heard people talking about better sound from a USB cable on this forum either. What bothered me was the realization that if Head-fi'ers are making posts like that, and even agreeing with one another on such patently false information (thus creating a consensus which can further sway others' opinions), how can I take anything that is posted here about the sound quality of amps, DACs, upgraded cables, or even headphones seriously? How likely is it that so and so amp doesn't actually increase sound stage or "musicality", but is purely placebo. Or a DAC or headphones. I've seen a confirmed case (usb cables), so that makes me wonder about every other opinion on sound quality that I read here. How much of this stuff is just in Head-fi'ers heads as a placebo affect? How much do we want the $300 upgraded Cardas headphone cables to be better so we hear it that way and post about it, thus priming others to feel the same way when they buy there's because now they heard it's better so they look for a change that isn't there -- and hear it. I feel like the natural group-think that online forums have contributes even further to this, echoing around each individuals placebo affect so that they not only get it from themselves but get it fed back to them in the form of a group consensus (which is a powerful force on the brains decision making processes and on the way we experience things). I'm interested in everyone's opinions on this. I don't have much personal experience with different equipment, so it's hard to evaluate others' evaluations because I don't have a good frame of reference. But reading things like that a USB cable noticeably improved sound that a DAC was putting out makes me take everything else with a HUGE grain of salt. Now on the flip side, I just bought a pair of Sennheiser HD600s (my first pro quality headphones) partially based on feedback I read here and they sound absolutely phenomenal -- worlds better than any headphones I've ever heard in my life. And they are highly reviewed here, so obviously there is good info here. I just wonder how much other info found on this forum is purely placebo.