Originally Posted by arnyk
4 words or 5: non-level matched sighted evaluation. They are invariably positive for audible differences no matter what.
Next possible source of audible differences is problems in the analog domain due to interfacing an output and an input on two separate chassis. This is not an audible problem with the analog output as such, but rather an interfacing problem that can generally be managed but not necessarily by an inexperienced audiophile.
I understand this place is science based, and I'm one of those types too. I don't believe in much difference between amps, cables of any kind etc, but I maintain without a doubt that my sound cards analog out is much worse sounding than the digital out regardless of which of the two receivers I used as DAC's, a Denon before and now a Harman Kardon which both sound identical as expected.
In fact, what drove me to buy a Toslink cable and try the digital out was that I was really disappointed in the sound quality I was getting from the analog out, as I assumed there would be no real difference, but once I connected the Toslink cable it was quite obvious. I even kept the analog and digital inputs connected for a bit and switched back and forth between them through the computer and it was not even close.
I would compare the difference to that of a 96k mp3 vs a 320k mp3 and probably even more extreme than that. I cannot speak for the OP, but he seems to be saying he experienced the same thing, or it sounds similar anyway.
I'll entertain theory's as to why that is because I'm not entirely sure why, but I won't entertain the idea that they sound the same because they simply do not. The Toslink cable was $5 or so, so it's not like I have a lot of money involved and wanted to hear a difference. Like I said, I only purchased a Toslink cable to see if the analog out was the problem and in my case it clearly was.
I seriously doubt the 3.5mm to RCA jack was the problem as I tried several, so it was either both of those cables, or the digital out sounds a lot better. I vote the latter.
When I had crappy "computer" speakers, I didn't really notice a problem, because the speakers sucked, but once I put together a real audio system, it sounded bad before I went to the digital out. It's already connected that way, and has been for several years and I have no intention of switching it back regardless of who says they sound the same. It's my setup, of course I've heard it, and they sound different. Maybe in theory they shouldn't, but they do, and that's a fact.