A few remarks about my experience with Ropiee and USB on the Raspberry Pi 4. To cut to the chase, I am satisfied.
The following DACs are in my Roon system: Chord 2Qute, Marantz HD-DAC1, McIntosh C47 preamp. Cables are Cardas Clear USB and Audioquest Cinnamon. The HD-DAC1 is used for headphone listening and the 2Qute for speakers. The McIntosh’s DAC sees little use, but it’s hooked up anyway.
Before the Pi 4, DACs were connected by USB to an i5 NUC running Roon Server. Music is stored on a portable 1TB USB 3.0 drive attached to the NUC. The NUC system sounded a lot better than what I was using before: DACs connected by USB to a Ryzen desktop computer running JRiver. Adding two Audioquest jitterbugs to the NUC further improved sound. I still had concerns that the NUC’s fan, i5 CPU and connection a USB drive could cause noise. As we know, a better solution is to isolate the Roon endpoint from the server. I avoided doing so with a 3rd generation Raspberry Pi since USB and Ethernet share the controller. Also, I was not interested in building a number of Pi 3’s with SPDIF hats and their cumbersome dual power requirements.
When I learned the Raspberry Pi 4 had separate controllers for USB and Ethernet, it seemed worth a shot. After all, it’s so cheap to build one, so why not. My goal was to have a silent fanless system, so I enclosed the Raspberry Pi 4 in a Flirc aluminum case. The case also acts as a heatsink, so if you have concerns about temps and cheapo plastic cases with fans, just get the Flirc.
Once Roon Server recognized Ropieee on the Pi 4, I configured the DACs. There is no upsampling on the Chord 2Qute. Whereas on the HD-DAC1 and C47, everything is upsampled to DSD128. The two AQ Jitterbugs are still in use. For the first sessions, I listened to the Chord 2Qute with a wide variety of music in PCM and SACD formats. What I can tell you is first impressions are very good. To my ears the Pi 4 running Ropieee was a noticeable improvement over connecting DACs to the NUC. There is an increase in detail, clarity, mid-range, bass, air and a wider soundstage. There has not been a dropout, crackle or any kind of extraneous noise, even when streaming DSD128 and 24/192 PCM.
The Raspberry Pi4 Ropiee project cost me $135 CAD and it’s money well spent. Improvements realized by isolating the endpoint from the server are easily heard and this solution costs less than many audiophile cables and yields arguably better results.
I cannot comment on whether a Raspberry Pi with an SPDIF hat would sound better. Nor can I say it is on par with a dedicated Roon USB solution like the MicroRendu. I have no experience with these devices. What I can recommend is building a Raspberry Pi4 Ropieee box if you currently attach USB DACs to a desktop computer or NUC running Roon Server. I also recommend using an AQ Jitterbug, or similar USB noise filter, between the Pi and your DAC.
