Lumin upgrade - built-in or separate DAC?


I've got the rest of my system sounding nice enough and since I mostly use my NAS or stream Tidal nowadays, I want to upgrade my digital front end from a Mytek Brooklyn DAC+ and Bluesound Node 2 (used as a streamer only) to something better. My local audio store says I will notice a huge improvement if I upgrade the streamer only and continue to use my current (Mytek) DAC. He suggested going with the Lumin U1 mini and a Sbooster linear power supply. I am already using a Sbooster for my DAC and have a Shunyata power cord on my Node 2. 

Does anyone have experience going from separate streamer and separate DAC to a combined unit? 
My thought is that if I have an "all in one" streamer/DAC, I can get rid of having to use 2 units that need cables to connect and less wires/connection in the signal path and ultimately better sound.

Here's what I'm considering (in no particular order):

*Save $ for about a year to buy the Lumin X1
*Buy a used Lumin S1
*Buy the full size Lumin U1 and use my current Mytek DAC
*Buy the Lumin U1 mini, another Sbooster and use my current Mytek DAC.

The rest of the system is pretty good (in my humble opinion). I have all the other pre-requisites such as good speakers, amp, speaker cables, dedicated lines with 10ga wiring, digital cable, interconnects. The other items I'm working on is room treatment and making stands to get the speakers right at ear level. 



 
veerossi
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Interesting.  I have the U1 but always thought the U1 mini came reasonably close in performance.  The isolation from the casing and power supply are definitely better in the U1 and plus the U1 can do DSD 512 and PCM 768Hz while the Mini only goes up to 256 and 384Hz.  Even dealers have strongly pushed for customers to go into the Mini.  I suppose this thread makes me glad I chose the U1.  I've heard the U1 really gets upgraded if you use the X1 power supply but I think that's an extra $2K and I'm not sure it's worth the bang for the buck.
Three easy payments: Does your U1 upsample cd quality flac to something better? If so, how is it?

what DAC are you using?
@veerossi  Yes, it upsamples  from 44.1kHz to DSD128.  You can find the complete specs here:  http://www.luminmusic.com/lumin-u1.html

I'm using a Lampizator Atlantic TRP DAC and have the units connected with a Sablon 2020 USB.  Really enjoying the pairing.