@ban25 Is right, should try another amp just to see if the Denon might be the culprit too, highly unlikely but you never know.
You can buy a Fosi Audio V3 for well under $100, I have 2 of them, they actually sound as good as amy expensive amps I have owned. Hard to believe, but true, and If it is returnable, you can either return it after, or keep it for the surr back or something.