audio noise after installing ML

[tmavomodry]

Hi there,
i know i should post this to bugs forum (and i did), but i wanted to ask here as well. after installing ML on my canon 600d, recording of audio started to add this strange noise into videos - not continuos but rather stopping every half a second or something around it and then - hissing again (i write hiss rather then noise because its really annoying high frequency hissing). any advice how could i get rid of it? i tried every video format (default, vbr...) but its still there. my camera didnt fall or anything and i was not doing anything with its mic..

[1%]

Ground loop?