DJM S9 - Audio Pops / Cracks Post Firmware & DLL Update

Weird issue.

Just updated firmware on S9 to latest versions - 1.09 on device, 1.110 on Windows 10 64bit.

Having cracks and pops with audio when used as windows audio device in iTunes.

This didn't happen before - have tested all cables / amps channels etc with CDJ - absolutely no problem. Obvs restarted everything several times.

Now - I've changed iTunes to play back in 48000 rather than 44100 - I think this has sorted it, I could see no way of changing the sample rate of the S9 though (is this correct?!)

Anyone else having this problem!?