New streamer needed

Sonos Connect Ultimo, a Sonos upgraded to a highend streamer by means of a better clock, power supply and spdif output. Done by Magna, a Dutch company, you likely don't know. But it doesn't matter as the cd transport was my reference.

As to the other points, I have asked a question in this forum. I am convinced everyone has tried his/her best to answer it, and I appreciate that. Some answers are more useful than others, but that is okay. It's my view that every answer has its merits.

very helpful.  You’re right, I don’t know anything about your modded Sonos, but the base Sonoscis likened to 44.1 khz, right? Whereas you DAC can handle up to 192 khz, right?  So in theiry, at least on some music, that could explain a difference in sound.  Again, hope that helps.

limited, not “likened”

It can handle 192, but that doesn't matter. I am looking for a streamer that matches the CD transport, not my previous streamer. I received some ideas what to look for, so that is good.

@mdalton well the way you react to what I post is your confirmation bias. 
@stievus a good way to look at it is everything has to more or less be on the level. What I mean is the quality of your transport has to at least match the quality of your DAC. There are products that punch above their price point but I’d say it’s not very common. Look at different streamer designs and what they’re optimized for. It’s important to understand that and how it might impact your digital front end performance, the synergy a particular streamer would have with your DAC.
In the case of Aurender N100, N150 and N200, Lumin U1 or U2…these are more USB optimized. The Aurender N10 and N20 have USB optimization but also feature a top notch OXCO clock for the SPDIF out. That gives you great performance if your DAC is geared more towards SPDIF signal processing.
If you have a DAC with a great USB section, you’d go for the N100, N150, N200 or any of the Lumin units. But that’s not to say the performance of the USB optimized streamer such as N200 is bad via SPDIF out. Trying it is the only way to know. 
Another aspect of it is power supplies. Linear power supplies in digital is almost always better than the switch mode type as the latter will pollute right back into the AC line potentially impacting other components in your system. 
Hope this helps. Take your time with your research and if possible audition streamers before buying. Good luck.