Acer Aspire microphone does not play nice with battery

Hi all, I have an Acer Aspire with a fresh install of kubuntu 12.04, newly updated.

The microphone is slightly less glitchy than under Lubuntu but still extremely problematic. I need the mic so that I can use my internet phone; this is a serious issue for me.

The microphone does not record if the computer is booted or woken from sleep while on battery power. No it is not automuted. Yes I have checked the mic boost. Plugged in, arecord works fine; under the described conditions it records a quiet hiss. Interestingly, adjusting the volume of the capture stream while recording changes the volume of the hiss. I have had sporadic success killing and then restarting pulseaudio, but the success isn't replicable. Removing pulseaudio kills arecord function completely.

Can anyone help with this issue? It has been plaguing me since i got this computer, largely for communication purposes.