Just to share! Headfonia has a short review on the HP-A4:
Seems hard to believe that the A4, with a completely different DAC chip, would be better characterized as a "mini-A8" than would the A3 (the latter of which has a very similar AK DAC chip to the A8). Can anyone explain how it could be otherwise? I'm quite open-minded and curious about the A4, just haven't had a chance to hear it yet. This review seems counter-intuitive in some ways. Is the A4 really more V-shaped than the A3? This would be very useful to know.