Comment 3 for bug 776949

I have now been able to workaround this problem with the advice from the post at http://ubuntuforums.org/showthread.php?p=10751019#post10751019

Essentially, adding the line:

options snd-hda-intel model=auto index=-0

to /etc/modprobe.d/alsa-base.conf seems to fix the issue.