Are your RCA and Power cable running side by side? If so, seperate them as the Current from the power wire can interfere with the RCA signal giving that whine. The shielding on the RCA's can also help reduce it, but that depends on the quality of the RCA's you have. Same happened to me in my Verada, seperated them and all is good. If all fails, may be a faulty RCA lead, replace and try again, it's all, unfortunately, trial and error.