hello all, thank you for taking the time out to read this. I have 4 brand new osd xmp 500's two are completely hooked up to an Atlas Ied zones 1 and 2. At start-up they go into protect mode immediately, I unboxed a third unit and plugged in the power source only with no other wires attached and it goes into protect mode as well. I haven't opened the fourth box yet... Any insight on this would be greatly appreciated.\n\nThank you.\n\n\nWhat speakers are you using? If they don't have a setting for 70V or 100V on the rear, you need to read the manual or talk to whoever sold these to you- these are commercial amplifiers what are called "constant voltage audio systems', meaning that the speakers need a transformer to reduce the voltage. 70\/100V systems use a higher voltage to prevent voltage drop over long speaker cable distances. \n\nIf you have no speaker wires connected and these amplifiers go into protection mode, they have problems- what line voltage was selected?