No sound coming through headphones DDJ-SR (or very little)

Hi,
I am having an issue with my controller in which there is very little or no sound coming out of my headphones. All the relevant buttons and knobs are where they should be. Running the latest firmware and software for Serato. Controller worked fine last time I used it which was 3 days ago.
I will add that when I plug in my iPod headphones and turn everything up, I van make out the song Im playing, with my Seinheisser DJ headphones I hear nothing.

As i am visiting family for a few days, my speakers are at home so I'm just playing through headphones currently. I left my normal usb for the ddj-sr at home and I had to buy a new USB 2.0 which is made by Belkin could this be the issue?

I think possibly but at the same time surely the headphone port requires little power or runs off the power being provided by the USB connection to laptop? On top of this everything else works fine by all account.

PLEASE help me, I'm lost without my SR functioning properly :(
Thank!