Initial impressions on my end with the HP-P1 are very positive, but I have not yet had an opportunity to really sit down and A/B versus my iBasso D6 or my RSA P-51 Mustang (as far as amps go). Judging by the improvements in sound that I do detect, the DAC is slightly better than the one in my iPhone 3GS (which, as an additional point of reference, I personally detected to already be noticeably better than the DACs in the iPod Classic and the iPod Nano). I will try to get some more critical listening and A/B comparison in when I can find the time and then I will report back. Suffice it to say that I am satisfied enough with the sound to definitely keep the HP-P1, but I still need the opportunity to quantify how much better I find the combination of iPhone 3GS + HP-P1 versus 3GS + D6 and 3GS + P-51.
Great to see another satisfied customer . I look forward to your impressions between the HP-P1's amp section and the P-51.