Best dac under $2500 - comparing build quality and technologies


I have been in the  Audio field for over 4 decades and have owned some pretty exclusive audio gear 
I was listening to a 3 years old R2R dac the R7 from AudioGD a 20 year old company which won several awards  which is not known much in the U.S yet  ,This New R8-MK2 is better still.
it is  very well built using 3 R core transformers rarely seen unless spending $$. Their latest and best value is the New R8 mk2 dac. This dac just came out late April 2021 ,over a year went into the redesign the Owner stated this unit has several advancements vs previous designs , and runs much cooler for less money then  the previous R7 but better ,their is also a mk2 R7 also as well as a Flagship R7 HE with power regeneration,which I wanted but could not afford .The dynamics and realism is what sets this apart it’s massive power supplies and over 130k uf 
of capacitance is more then most amps has a lot to do with it I will be getting my dac next week and put side by side with  very well know competitors  it was noticeable better  in several areas , and it has 7 sonic adjustments all FPGA based 
4- non over sampling ,including a vinyl mode, and 3 over sampling  other dacs just a minor OS option 
you literally can Taylor the sound to your audio system .it weighs 26 lbs ,Underwood Wally is now the U.S distributor and service center  . I will give a full rundown once I have logged a week or two on it ,2 R- core transformers go to the pure class A  analog output section, the 3 rd transformer -digital is now fully servo controlled and runs much cooler and much better specifications . Check out link below.
http://www.audio-gd.com/R2R/R8mk2/R8mk2EN.htm
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we Directly compared the Denafrips Pontus at the audio get together it was very refined a bit laid back  the pontus  very similar to the Holo springs 2. I  owned the latest Schiit Yggsdrasil last year and bought the latest board very neutral very good dynamics too cool for my taste, but none of these others have the prat and shear scale of dynamics and musical density ,and it has 7 real user adjustments FPGA in its programming 
4 non oversampling ,one vinyl ,and 3 over sampling .a very hard dac to say 
what it sounds like you can literally Taylor to your audio taste. The 3 R core transformers 2 - in pure class A for the analog output stage , and 1 for the Digital with 130,000 uf in capacitance which is more then most amps,gives it a big advantage to most dacs out there ,most certainly in its price class under$2500
And uses with the latest servo technologies so runs much cooler,with lower distortion levels. It is a very large dac and  at 26 lbs it requires a whole shelf.
Not much more to add ,just read all past R7 reviews and that is a good starting point . I will say their New top  R7 mk2 is noticeable better still I was told and  their flagship    R7 HE MK2 looks fantastic and has power regeneration built in and output to a master clock option. I will give it a good workout for a  week or two then give a honest mini  review .
In the winter of 2020, another collector of vintage audio introduced me to the DAC difference.  Then, my 30-something nephew let me borrow his Shiit Modi. Damn, I thought, for under $100. it made that much difference?  So, down the rabbit hole I went. I'm basically a 2-channel, no subwoofer, silver-faced receiver/amp 70's audiophile who enjoys vinyl and the basics that I grew up with.  My cd collection was pretty much sitting on shelves collecting dust.  A year later and with much research for something in the under 1k range, I bought the Denafrips Ares II (R2R) and the Shiit Bifrost 2.  I've been very impressed with the Denafrips, pulling out cds I haven't listened to for years.  My jaw dropped. The Shiit has been slow getting here due to parts shortages, but it's finally on it's way. Looking forward to hearing an R2R DAC along with a Delta Sigma type.  But, not sure I will be able to tell the difference.   All I know is a DAC has definitely made me pull out the cds and enjoy them in a way I never knew possible.  I look forward to following this discussion to hear other users opinions and experiences. 
@kyguy1 - what speakers? Bifrost is super. But depending on the rest of your setup, DAC will only make so much of a difference. I couldn’t hear much of a difference between Modius (200 bucks, one up from Modi) or Bifrost (700 bucks). But a preamp makes a meaningful difference. Or an upgrade to a proper level, like Gangnir in the Schitt world, or RME ADI-2 FS. The germans know what they're doing. That's a super DAC, with PEQ options.