I just installed a Scosche rf modulator from Crutchfield and it works fine with one problem - when I remove the iPod and shut off the radio and turn off the car and remove the key I hear a faint hissing sound coming out of the speakers. I went so far as to remove the power to the modulator (i.e., pulled the power connection from the fuse box) and I still get the hissing sound. It shut off after about ten minutes. Any one else run into this problem? Is there some sort of power bleed through the radio back through the antenna?