BlessingX,
Yes, they are 50 ohms
Mirumu,
The 555s bass bloat is good with some thin sounding portables though like the newer sony PCDPs but out of my headfive with crossfeed on, which I love by the way, The 555s bass around the 80 to 100 hz sticks out more. I think its just because its the first time I got to listen to them this loud and clean compared to the time Ive been hooking them up with less powerful jacks. The bloat is OK when at low volumes with thin sounding sources which is probably why many people say why the 595s need an amp to shine. The 595s, even though not power hungry, need an amp for all its nuances to be appreciated. I'll also try them with my cousins top loading CEC CD Player to see what it sounds like with a good source. hmmmm or should I? I hate upgradeitus
One things for sure about the 595s though is that they play all my music good unlike the 555 which is more picky to play music that doesn't touch its flawed frequency ranges as much. The 555s dark upper mids really make some vocals and instruments dull on a lot of alternative rock recordings. Im at about 15 hours burn in now. I'll post more impressions once I get to 50 or 100 hours and when I try them with different sources and a variety of music.
On a side note, from my memory of my ms1s being compared to my hd555s. I have a different view from a lot of the posters in headfi where I thought the 555s more exciting and fun. I thought the ms1s with comfies w/ quarter mod was bland spatially and although it had livelier lower treble, didn't sound as real in the treble region with cymbals. The 595s take the 555s up a good notch. I no longer crave the grado immediacy which I always had a craving for (The sr60s had more of this great immediacy than the ms1 BTW), The 595s have this immediacy. Of course I haven't heard the RS1s.
I tried buying the beyer 990 05s thinking they would have sort of a grado immediacy which I find very important to be combined with a refinement which makes instruments sound more realistic/organic. This combination of traits is what I find fun and satisfying. The beyers went the opposite direction. No immediacy! midrange sounds flat and uninvolving to me. The 990s bass is nice though.
I envy you guys in the US for having so many meets where you could really try before you buy