i have exactly the same problem with my new HTPC and my pioneer VSX-527.
I Have an i4130 and H87N so running HD4400
Have upgraded to latest F5 Bios and running latest HD drivers but it still loses audio when the amp is turned off And back On again.
Only way I was able to stop this was via using an older driver 10.18.10.3038 which installed via gigabyte love update but now I can't find this driver.
INtel please ease hurry and sort this as the issue is not resolved in driver 3142