The written spec was impressive, as were many customer reviews, but my experience matched a negative comment regarding the intrusive sound.On start-up there was a promising silence, but whichever source was selected, an electrical noise [sounding like a badly tuned radio] was a constant. Not significant with louder music, but in quieter music and between tracks it became distracting. I tried several times to identify the cause - each time with the same result. Since it was present on CD, Bluetooth, Radio and Aux, I suspect the amplifier processer, but obviously I can't be sure. A great pity: the unit looks OK, and had all the features I want, so perhaps I was just unlucky.