Comparisons between ultra and PRO finished .
1. The ultra is slightly better sounding as digital transport to my external dac , there is a more exact stereo image but the difference is small compared to the pro, maybe a 2% better sound.
2. Asynkron usb vs electrical spdif from the Ultra : the spdif sounds very magical with a good flow of the music.
The bass from the Rega dac R is very tight this way.
Using usb from ultra to Rega dac R : sounds a little different in the bass, but the difference is very, very small. I prefer the electrical spdif connection because the bass gets a tiny bit tighter. Maybe the Rega is optimised to sound the best through spdif ?
3. The ultras internal dac compared to Rega dac R :
The Rega wins with all connections. The difference is like this- If the ultra is 90 % sound quality then the Rega is 95%.
The Ultras midrange is slightly shut in and the difference between different cymbals is smaller with the ultras internal dac. The sound gets a little better using minimum phase, fast rolloff digital filter on the ultra. But not really as good as the Rega.
However … the ultras internal dac sounds way better than the Pro:s internal dac. With PRO rca out you get 80% soundquality.
4. Using Toslink from PRO to Rega and from ultra to Rega :
Sounds slightly worse than electrical spdif from both PRO and Ultra. I dont know the reason for that.
5. The ultra streamer alone with internal dac is not as good sounding as the WiiM PRO, lps, - electrical spdif - Rega dac R .
The Linn klimax renew DS sounds slightly better than the ultra without using external dac.
6. As digital transport to a good sounding dac the Ultra is slightly better than the pro with a linear power supply . Using the stock power supply on the pro makes the difference slightly bigger.
7. Both the Ultra and the Pro is better sounding as transports than my Apple m1 computer and my Yamaha wxc50.
There it is , good news is that used as a transport , the ultra is of highend quality.
As a completely streamer the ultra sounds very good, much better than Yamaha wxc50 and better than a laptop to external dac.
Now, Im sure many youtubers gonna continue to tell lies about the digital outputs of the WiiMs , but remember they make their living selling more expensive streamers than the Ultra.
Edit: every digital output from the Ultra did function very well, even the USB output could regulate the volume control .