Sennheiser HD 555 - efficient enough w/o an amp?

[phallumontis]

I'm thinking about buying these phones since they're only $100 on Amazon and that's roughly my budget, but I'm wondering if they're efficient enough to hook up to an iPod or other fairly low-power device and still get good sound. I don't know enough about ohms and dB's to be able to tell just by reading the specs. Or should I just get the HD280's? Any help would be great. Thanks!

[Dougr33]

I'm terrible with budgets, so don't take my advice!
Okay, here's my advice. I've owned the 555, and the 595. On my pretty decent Arcam setup, the 595 was MUCH better... clarity, tonality, etc. Also, the 595 is available as 50 ohm, and sounded great (and loud) driven by my Palm Treo 700 for mp3s. They're usually on ebay for about $170 shipped. Make sure it's the 50 ohm version (most common, but some are 150 I think). I know it's another $70, but the 595s really approach 'world-class', the 555s are just 'excellent' (and harder to drive).