Jaw Dropping Improvement?


60-something, intermittent earner here (Read “mostly starving-artist with the rare, unexpected windfall here and there.”) who has just acquired a Bluesound Node 2i.  I’d be very interested to hear what external DAC, in your experience-and-opinion gave such a dramatic improvement in SQ over that of a stock Bluesound streaming device as to be jaw dropping...an absolute game changer.  Does such an animal exist for less than $2000 U.S. or are improvements at this price point more in the nature of subtleties?  Somewhere in between?  To be sure these things are subjective but your take on this would give me a running start on researching things here with a fairly tight budget being considered — If subtle-to-low/moderate level “tweaks” to SQ are all I can expect from, say, a Qutest or Gungnir Multibit, I’ll probably stay with just the streamer and be happy.

Thanks in advance.
lg1
+1 for a pre-owned Ayre Codex. But here is an interesting question. At your age I discovered I suffered from hearing loss at frequencies above 3k Hz. It is a common issue.  Have you any suspicion that it may be the case for you? If so, a visit to a good audiologist and, if necessary, a quality hearing aid could be a better use of your funds. 
I am sure the cheap ProJect S2 DAC I added to my Bluesound Node 2i might have been the problem.  I have heard the Cuttest is much better.  What would I hear with a more expensive DAC that would sound better than the Bluesound played by itself?  I like hearing detail especially the highs and bass.  However, my two REL S2 SHO's subs fill in the bass nicely.  I for some reason think I like MQA, but is it like the Emperors New Cloths am I convincing myself it sounds better?  Adding a DAC is supposed to stop the complete unfold of MQA.  I wonder what others hear when they play MQA?  
It’s certainly worthwhile experimenting with DACs to put on the end of your Bluesound - I find that if the rest of the system is balanced with a good pair of revealing speakers (mine are Role Audio Enterprise I highly recommend these!) - then an upgrade in your digital upstream makes a very worthwhile difference.
I am partial to a good R-2R DAC in my experiences so far, although many have jumped onto the Chord bandwagon. Digital can more incisive and impactful without being harsh when you get it right.
The streamer does make a difference too - I have had the Bluesound Node 2i in my system before - but preferred the sound of an Auralic Mini (as a transport) but it did have the advantage of Auralic's Linear PSU - however I do agree that the Node has a better GUI.
Teac NT-505, SMSL M400, Topping d90...all sound better than Bluesound Node, which can be used as a streaming device if desired...
i have told this story before. i had a PreSonus Audiobox USB DAC (XLR outputs) that cost me a whopping 79 bucks including shipping. I was sure that I was missing something. $200 later with a SMSL SU8, I cannot hear a bloody difference. I would like to try the TEAC NT-505 when I get 2000 bucks to burn on something else I won't hear a difference from...