John Sciacca

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. Is there something I’m not thinking about correctly? —Jeremiah Rogers

Q Bluesound’s Node streamer has a built-in DAC and costs around $500. Meanwhile, Lumin, Linn, and Naim sell streamers without built-in DACs for over $2,000 or $3,000. What do these more expensive streamers do to the signal that justifies the extra expense? And if the digital output from these pricier streamers is of higher “quality,” can a high-quality DAC compensate for a lower-priced streamer with a “lower quality” output? — Reginald Tinsley

Q I have a vintage preamp that I love (Audible Illusions 2C) but really need to be able to have remote volume control. Ten years ago, there seemed to be some good options for adding a volume control between a preamp and amp that were not very expensive. I am not finding anything reasonable now. Any ideas? —Michael O’Connor

Q When I’m streaming 4K through my Roku Ultra, I occasionally get an onscreen warning that says “not 4K-compatible.” I also have a Panasonic DP-UB9000 Ultra HD Blu-ray player but there’s no issue with it. Every check I make shows that I am set up properly for 4K streaming and my Wi-Fi signal to the Roku is great. Any ideas? It’s making me crazy. —Michael Henn, via email