Does anyone have hiss problems with either the dbx or Denon? I haven't tried the Denon, but the dbx seems to output a constant low level hiss. If I unhook the dbx from the amp it's scilent. If I plug the dbx into the amp with no inputs into the dbx it hisses. I thought about trying the Denon to see it it's quieter but wanted to check your thoughts first.