Got a tech question for Sound & Vision? Email us at AskSandV@gmail.com Q I have a Yamaha WXA-50 amplifier, and I would like to play hi-res audio from Apple Music and get the full benefit through the amp. In my mind, I would buy a DAC capable of connecting through USB to my iPhone, then to my amplifier’s digital audio-in. Most DACs seem to only have RCA outputs, but it seems to me that the purest experience is to “stay digital” until the amplifier converts to analog.