what is supplying the phantom power to the akg's?
also, is your buddy using line level converters to convert the mic level signal to a line level signal?
i used to run akg 391 > B8 phantom power supplies > line level converters > sbm-1 > d8 and had decent results. but without phantom power and line lever converters, i am not sure how your budy can be running those akg's.