I've recently purchased and setup an RPi 4 with a HiFiBerry DAC2 HD. This runs as a Roon endpoint via the Roopieee OS.
The DAC2 HD is connected to my Denon AVC-X3800H AV receiver via the RCA connections on the DAC2 HD board to the Aux RCA input on the Denon. I am using this to play Hi Res audio from Qobuz (via a Roon core) with sample rates upto 192/24.
A likeminded friend has questioned if I am getting the true Hi Res at the true sample rate, this is entirely because as I am connected via RCA cables which he believes are limiting me to 44.1khz if input to an Aux/CD type RCA connection.
Having researched it quite a bit, I have concluded that there should be no limiting factor via the RCA cables as the DAC has already converted the audio signal, so it's pure analog that is being sent to the Denon, which in theory should not be limited? My friend is still questioning this though, which is leading to me questioning it again.
I just wanted to put it out there and get some other opinions. Can anyone advise?
If you are wondering why I am not using the built in network streamer capability of the Denon, it's because it's only Roon tested, and not Roon Ready, which means I am limited to Airplay2 at 48khz. The RPi DAC was my cunning way around this.