See if your current IA has Pre Out. Usually most IA’s have Line Level Out and hooking up a PA using Line Out is not a great idea. You will have no control over the volume unless you can find a PA which has Singe volume control for all channels or has a remote to control the volume easily.
Line out has a fixed voltage signal unaffected by the volume control.
Pre-out is normally a variable signal since it is intended to be connected to a power amp, in this case adjusting the volume control adjusts the output signal level as a power amp is traditionally fixed gain.