Eq hiss

Hey guys. I have a MA Audio 30eqx that hisses when powered up even though the gains are turned all the way down and there is nothing plugged into the inputs. I know it's not the amps because my eqt's don't do it when I hook them up or go straight into the amp from the head unit. I know MA Audio is kinda crappy but this sounds like there is something wrong with the eq. Its the same hiss you would get when gains are turned all the eay up but they arent. Any ideas?