Yeah there's usually a noise turning them on and off, but this noise is definitely different (and new). It's loud, kind of like a crackle or a crunch...loud enough that I could hear it about 30cm-1m away. Plus the earcups vibrate (not just a little either), so I'm thinking there's an issue.
I'm thinking of going to the 'authorised service' place in Moorabbin tomorrow, might help to get someone who actually knows what they're doing to have a listen...
Considering I've only used them about 6 times, I'm not too pleased