Next Best Upgrade for Tidal MQA?


I’m trying to decide what my next best upgrade is going to be to improve my streaming music quality (predominantly Tidal, and Tidal MQA, when available).

Current setup:
KEF R11
Custom Deep Sea Sound 18” subs (2)
Marantz SR7012 AVR
Bluesound Node 2i
MyTek Liberty DAC
Parasound A21+

I’m wondering if I’ll get a bigger jump from inserting a Parasound JC2 BP as a pre-amp or replacing the DAC/Streamer with a MyTek Brooklyn Bridge? Or is there something else out there in the $2500-4000 range that will help make a significant jump?

Help and thoughts appreciated!

128x128bruxesq
info provided is useful, but you need to say what is it about the sound of your system do you want improved while streaming...
All of the Mytek DAC products are going to have a similar house sound so swapping one Mytek for another won't really change anything.  I would look at adding a tube preamp in place of the Marantz. 
I’m generally happy with the sound, but always chasing the cleaner, clearer, better separation, more dynamic, more lifelike...

To answer the question differently, I have a perceived weakness in the Marantz, and then to a lesser extent the DAC, and to an even lesser extent the Streamer... 

I recently went from the A23+ to the A21+ and it was a big jump, so I think there may be headroom in replacing some of the other components.

Suggestions on a tube preamp? Why tube?
I would want some more warmth and body to the sound to balance out the Mytek and the Parasound, but that's just me.