Has anyone got the specifications, signal to noise ratio, etc for the Karma.

I'm surprised that this information was not on the www.rioaudio.com site. Not even in the PDF manual. That's too bad! I think that information is in the FAQ section at riovolution for you to look up.

he wants to compare it with the iPod before making his mind up.

Interestingly, regardless of technical details like S/N ratio, I've seen people argue both directions about which of the two has the better perceived sound quality. The two players sound different, I assume because their outputs have different EQ curves coming out of the DACs. Some people like the way the iPod sounds better, others like the way the Karma sounds better. I recommend that your friend take his favorite pair of headphones into a store that's got a floor demo model and try them both out.

Finding a store with a floor demo might be hard. I saw one once, in a Magnolia Hi-Fi store.

Something to consider. The Karma has a 5-band parametric equalizer. I don't know if the iPod has a parametric one or not. But with a parametric EQ, you can tailor the sound to your liking if you're willing to do the work.

Note that one of the biggest advantages the Karma has over the iPod is battery life, so definitely make sure he knows about that when making his decision.