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
128x128audioman58
While not specifically a DAC, the Cambridge Audio 851n is awesome, and only blemished by a shifty app. Streamer by category, is has several inputs and balanced/ RCA outputs. Preamp function is built in, but can  be disabled. 
There are no standards… some people can’t hear the difference between a Best Buy special and a high end equipment.

Wait a minute! You can't talk about my wife like that!!!
Regarding Cambridge app, the new version of StreamMagic is pretty good. Right on par with LUMIN or Heos I’d say. Step below BlueOS. Haven’t tried roon 
I stream all my music through a Cambridge VNX V2 with the Preamp and DAC enabled, sounds great to me. $750.....Acoustat Spectra 33's with Roy E. Modded Acoustat TNT200 Monoblocks..