Running 13.10 with a PNY GT 430, all was working well the night before. However, now there is no sound when 5.1 is selected in manager. If I switch to stereo HDMI then audio works. Nothing was changed so not sure why this happened. Tried rolling drivers back and then upgraded to latest with no effect. Swapped to different video card (GT620) but still no 5.1 audio.

Any suggestions would be welcome.

Thanks
Andrew