MSB Diamond DAC V

Try a Mola Mola Tambaqui Dac 

https://www.mola-mola.nl/tambaqui.php

For the price I would ask to see measurements on it. What's the SINAD? Intermodulation distortion? Jitter noise? Linearity? What you're describing is typical "ladder dac" high frequency roll off and distortion. I would expect that in a cheap R2R implementation not something at this price.

Once you've reached transparency in DACs, your noise floor is ridiculously low which even some inexpensive DACs will do you're paying for features. Some DACs add coloration with tubes, filters etc.. which negates transparency but some people like that nothing wrong with it. If you want to hear what's on the recording then transparency is what you're after and once that is achieved the DAC is one of the less important components in the system. Your speakers will have way more distortion than even inexpensive DACs that are considered transparent. Some R2R DACs will be transparent,  I would assume the MSB is considering the cost but after what gregm said I would ask them for some measurements. Other than That I wouldn't worry to much just get the DAC or Streamer/DAC that has the features you want. 

@tomic601

@gregm what is the other DAC ? I have no reason to doubt and would love to learn

He mentioned the Ideon Absolute in his first post.