One thing to watch is some times there is just one button that will supply phantom power to all XLRs on the board. This is fine if all the mics plugged into the board require phantom power however SM57s and SM58s will make a very bad noise if you send 48v up their output !
My instructors page and www.studiotrax.net for all things recording.
my toons Brought to you by Dr BadGAS
my toons Brought to you by Dr BadGAS