Do I still need a DDC in between?

@moonwatcher You are welcome.  It is interesting that you are curious about the Rivo+ jitter performance.  There is no measurement yet since it is just released but I found the measurement for Motivo, which is basically Rivio+ plus the DAC and headphone amp.  Their streaming circuit and performance is neck to neck according to iiwi but the Rivo+ has a slight edge.  See below.

The average (Lt / Rt channel combined) RMS (or so-called 1-sigma) jitter is around 8.2ps (I am not sure which output this measurement is taken from though). See yellow highlighted.  Quite impressive.  

So instead of calling internal clock in dac I2S clock, it is most commonly or rightly called the master clock, this clock positioned adjacent to digital to analog conversion circuitry. Only a ddc or streamer with I2S clock can replace the internal master clock in dac. Using usb or any other input cannot defeat or bypass the internal master clock. The only reason external I2S clock can replace this dac master clock is it's use of I2S protocol. 

Wait I’m confused….

I thought there isn’t a scenario where the DAC master clock is bypassed. Doesn’t matter what input you use the DAC clock has to provide timing reference for the Digital to analog conversion. Where is it stated that the internal clock is bypassed if i2s input is used? 
Is there a clock sync on the LAiV DAC?

Once again, if the user opts for the "I2S clock," the DAC or micro DAC will be slaved to the DDC’s clock and will use the I2S clock unless it becomes unstable or incompatible. This is a unique design feature of the Harmony. Still not convinced? Take a look at Harmony’s email response:

When you select “I2S Clock” and it is stable and compatible, the µDAC will indeed lock to and use the incoming I2S clock signal instead of its internal local DAC clock.

In this case, the local DAC clock is effectively bypassed, meaning it is not used during playback. The µDAC will rely fully on the external I2S clock.

It is amazing that some AGs here presume they know everything...

@lanx0003 I don't know what you're problem is, yes, I'm agreeing with you, the ddc clock bypasses the dac local clock, I've only said the same thing time after time! Perhaps I've called it internal I2S clock, local clock, master clock, its all the same thing. You really need to gain some reading comprehension skills, I'm done with this silliness.