I always thought that the Amiga's distinctive sound was because of it's poor quality basic DAC with no oversampling/interpolation like what a real audio DAC should have (such as any CD player or sound card).
I'm not knocking Paula, I like it as well, but I just assumed that was the reason.
Even with well calibrated 14-bit output (Cybersound), at 44.1 KHz, the top end is still noticeably grainy (truthful to real CD quality if you like), and I'm guessing it's simply to do with total lack of oversampling/interpolation. The audio filter built into the Amiga can clean the distortion up to some extent.
