I am asking for advice. I just received King STM. For a little background Ive had 2 stereo receivers, and recently an av by Denon. Im a music guy 1st. In my system I have an Oppo 103D with DACs RC to Balanced to my King which in turn drives my Buchardt 400s. I am seeking advice on maybe a RCA switch or Preamp. I have an 1970s Technics 1700 turntable, a sonos Connect. Also Im thinking about a sub in near future. I would appreciate any suggestions.