Do I still need a DDC in between?


This is my current rig:

Wiim Ultra (DH Labs Mirage / Cardas Clear USB, 0.5m) → Gustard U18 (DH Labs HDMI 2.1, 0.5m) → Harmony μDAC (Mogami quad XLR) → Parasound A23 (Belden 5T00UP) → Wharfedale Linton

The sound is very good to my ears—excellent tonality, detail, and especially soundstage, with impressive height and depth. However, I’m considering trying the Volumio Rivo Plus released recently, which offers an I²S-over-HDMI connection.

My question is: would I still need the DDC (i.e., Gustard U18) in between, or would a direct I²S connection from the Rivo+ to the Harmony μDAC deliver comparable or even better sound quality? Have you had any direct or similar experience with this kind of setup? Any advice would be appreciated.

lanx0003

If you're not syncing dac to any outboard clock whether it be in ddc or streamer doesn't much matter. If you're syncing have to compare clocks in the two units. Also, evaluating quality of clocks involves how they are implemented, not only clock quality but also power supply to the clock. Quality of I2S cable also matters, no longer than .5m. By the way, I have Harmony with Denafrips Gaia DDC, sync'd to Gaia via Tubulus Ximius I2S cable. This superior to optimized usb vis Sonore OpticalRendu via Audioquest Diamond usb.

Good question.  Probably comes down to which clock is better and not sure if Volumio offers galvanic isolation, which is important (assume the U18 does?).  At the very least you’ll likely get a better quality streamer either way, so given the unknowns this seems like one of those situations where just getting the Volumio and trying it with the U18 is really the only way to know.  Sorry, I know that’s not terribly helpful.  Best of luck. 

The harmony (micro) Dac is the only Dac I know so far that allows one to choose which clock to go with, I2s vs local (dac) clock.  I try both and it seems local clock option yield slight better SQ but I won’t swear to it.  Both units (U18 & micro Dac) might have similar grade of clock.  I use Ifi Ipower X for the micro Dac and I use 0.5m DHL hdmi 2.1 cable as shown earlier.

With that said, @sns, what you have said below confuses me a bit and please provide some clarification.

By the way, I have Harmony with Denafrips Gaia DDC, sync’d to Gaia via Tubulus Ximius I2S cable. 

What clock option you have chosen in Harmony Dac to sync., local (dac) or i2s clock?

This superior to optimized usb vis Sonore OpticalRendu via Audioquest Diamond usb.

This makes sense.  The U18/micro DAC via I2s also outperforms the usb (galvanized isolated) input on micro Dac BUT that is because of the weaker source (Wiim Ultra; but still very good when combined with DDC).  That is why I am thinking about the upgrade.

Yes, @soix, the U18 has galvanic isolation on its USB input, and so does the Micro DAC. As I mentioned earlier, the Micro DAC also allows the user to select either the I²S or the local clock, and I slightly prefer using the local clock.

The reason I'm asking now is because the return deadline for the U18 will have passed by the time the Rivo+ arrives.

Anyway, thank you for your response.

i2s may or may not sound better 

with digital it all depends on implementation