[lostinthesauce]

Really ?

Yes, I know it's with a Denafrips DAC but it is also youtube. I hear differences.

Thanks for the example; even with all the caveats (tired old ears, youtube compression, playing it out of a Marshall Stanmore) I could also here differences. I am cynical, but let's assume there's no tomfoolery going on. I.E. the microphone placement hasn't changed, volume matching was going on, sampling mode and filter selection remained the same, etc. Has the person who posted that video taken the time to compare the Denafrips USB stage against its SPDIF stage on anything else? Designing electronics is obviously hard otherwise all of us would be doing it. It raises the question if the company's implementation of USB is as good as their implementation of SPDIF. Note that I am not claiming their USB implementation is poor (that could be a counterclaim to the "Raspberry Pi has noisy USB proven with their DAC") but rather seeing a trend from a single data point rather than looking at the overall representation is like taking a lion home after seeing one perform in the zoo.

Another test, in addition to cross-referencing the Denafrip's USB performance on a different machine I mentioned above, would be to use a USB to SPDIF connector on the Raspberry Pi and compare that to the HAT version of the SPDIF connection. This isolates the Denafrip's USB to DAC stage from the test and any sound changes could definitely be blamed on the Raspberry Pi's USB ports rather than leaving a lingering doubt as to whether the Denafrip has any role in the sound signature change.

 

[GunGrave]

Understandable to ask these questions. I would veer on the side of common sense: The Denafrips is a top end DAC so it is plausible that it's usb and optical implementations are very very good. On the other hand, the PIs USB connection is not really designed (or budgeted) with HIFI in mind. The HAT is designed for that, but it a modest budget (compared to the DAC).
I would say the difference comes from the PI.

You are not really that cynical as you have not pointed out the cables are different