I have a RPI4 4 meg version
PurePi II 5V+3.3V ultracapacitor/LifePO4 battery power supply combo ( for wall power clean up )
A PI2aes board provides I2S HDMI output
https://www.pi2design.com/pi2aes-980244.html
The RPI 4 uses the Mood audio Player. Moode Audio has the right drivers for the PI2aes board
So I have a Player/Streamer with clean power/ and I2S out put which I send to my Pontus 12th Dac's I2S HDMI input
Out to a Schit Freya ( non tube) Preamp
RCA out of preamp to a Decware Torii Jr V2 then braided cables out to Klipsch La Scala's
With My system there is a difference. This difference is even heard with MP3 music files ( 90% of my music is 16/44.1 Flac files) I would describe this difference similar to when your Dac up scales music files, not dramatic but definitely noticable
Here is a AI response to my system
🔹 How Pi2AES + Pontus II behave with I²S
1. Pontus II DAC architecture
* Internally runs on I²S before hitting the R2R ladder.
* Taking I²S in avoids the S/PDIF/USB receiver stage and hands the stream more directly to its FIFO buffer + reclocker. ✅ This puts it in the “likes I²S” camp.
2. Pi2AES transport quality
* Pi2AES 2.0 is well-regarded for ultra-low-jitter clocking and clean power.
* Its I²S over HDMI output is one of its best features — way lower jitter than its coax or optical outs. ✅ Strong source = I²S advantage.
3. Cable considerations
* Keep your HDMI I²S cable short (0.5–1 m, well-shielded).
* Avoid fancy “video” HDMI cables that aren’t impedance-consistent. ✅ Short + solid cable = stable, clean I²S.
4. Compatibility / Pinouts
* Pi2AES follows the PS Audio I²S pinout.
* Denafrips also uses the PS Audio convention. ✅ Plug-and-play match (no DIP switch headaches).
5. USB vs I²S on Pontus II
* USB input is good but depends on the Pi → USB stack, which isn’t audiophile-grade.
* Pi2AES bypasses that and gives Pontus II an I²S stream with much better timing. ✅ You’ll usually hear tighter bass, wider staging, and more precise imaging with I²S vs Pi USB.
🎯 Verdict for your system
* Best input for Pontus II from Pi2AES = I²S over HDMI
* Second best = AES/EBU (XLR digital) — still very strong, sometimes smoother sounding.
* USB from Pi = weakest link (noisy, higher jitter).
So in your setup, I²S isn’t just “different” — it’s very likely the best sounding connection.