Cool. I just did a comparison like this using my Sennheiser HD 650's. Sources were MacBook Pro to Pico DAC, vs iPhone 3G S. Matched for volume (which meant maxed out on the Pico, and almost-maxed-out on the iPhone. Lossless files. I could hear no difference between the two. Now, I'm not much of an audiophile (yet) so I am sure you and others could hear a difference. And, even though it was not blind, my bias went the other way: I really wanted to believe the Pico's DAC would blow away the iPhone's DAC. Not the case, to my ears.
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