Edit: Full RE-ZERO review has now been added to my Multi-IEM review thread (here).
For completeness, a list of other RE-ZERO reviews:
[Review] Hifiman RE-Zero by rawrster
HiFiMAN RE-ZERO Review by mark2410
REVIEW: HiFiMAN RE-ZERO by LeonWho
REVIEW - HiFiMan RE-ZERO: Things Have Changed by TheGame21x
First impressions then. I have quite literally only been listening to them for only an hour. After using a set of Sennheiser IE8s all day, I need to re-tune myself to analytical sound before saying anything conclusive. I will say this: bass depth seems to be improved slightly compared to the RE0 but don't expect bass monsters - they are still rolled off in the lowest octave and extremely tight and controlled all-around. Despite the 16-ohm nominal impedance, they don't appear to pick up much hiss from my netbook.
The 4-pole plug of the RE-ZERO is configured for use in a balanced configuration (with a ground for each channel). What that means in practice is that the right channel is lost when it is plugged directly into a standard mp3 player headphone jack (tried with S:Flo2, Sansa Fuze, AMP3, and Cube C30) and requires the single-ended adapter to function properly (see pics below).
Edit: A soft adapter will indeed be included with the final production version.
On to the photos, then. First off, the box is identical to the RE0 v.3 and RE252 boxes - thick plastic, foam insert, hinged, etc.
The accessory pack is similar to the RE0 - a pair of large bi-flange tips, S/M/L single-flanges, a shirt clip, 5 pairs of replacement filters, plus the single-ended adapter and a pair of i-don't-know-what (bottom left) (Edit: The i-don't-know-what was mistakenly added to my RE-ZERO and does not belong)
The RE-ZEROs themselves are indeed identical to the v3 RE0. The y-split has HiFiMan branding as well as the text 'RE-ZERO'
The 4-pole plug fit into an adapter that appears to share a casing with generic 3.5mm splitters of the $0.99 variety.
And the whole thing plugged into my hapless Sansa Fuze:
Update: Just got an updated version of the adapter, thanks to Fang (the best customer service is still that which happens unprompted).
Pic of the new adapter, for those who haven't seen it:
And a pic of the RE-ZERO with the adapter attached. Obviously there's the issue of the 'kink' in the cable that occurs because the ZERO's native plug is angled, but it's a small price to pay for an adapter that actually works. Also, something I haven't thought of before - cable problems that often occur at the jack will not be much of a danger to the RE-ZERO - all that would need replacement is the adapter.
Edited by ljokerl - 8/23/10 at 7:24pm