Thanks for your answers. My SU-6 is connected through RCA cable to an old analogic amplifier (no remote control usable). I set the volume of my amplifier at half, the SU-6 at max volume (following your advices) and use the Wiim to control the volume through the remote control. When I was using the Wiim Pro (without remote control), my amplifier volume was set as it is and was controlling the volume through the SU-6.