DAC upgrade suggestion

Out of curiosity, I search for review of the NFB-2 and found the one below.  I am surprised, it is exactly how I feel about it.  It also mentioned that the designer is aware that it won’t have good test result due to non-feedback, but it will sound smooth and good to human ear, which also seems spot on.  Hmmm after all, it seems the designer know something, LoL.  
If I like this sound, maybe I should stay with this brand, talk to the designer and see what is the best upgrade option that improves the dynamics and clear out, at the same time keeping the same smoothness.

https://darko.audio/2010/12/audio-gd-nfb-2-dac-19-series/

Forgot to mention, the Audio-gd has a in-house developed R2R chip, while the MHDT use an old TDS1541a.  Although the TDA 1541a has good reviews, but if Audio-GD do it right, a new technology should theoretically sound better.  And with the positive review in 6moons, I hope it means it is done right.  This is another pro to go with Audio-gd.

Actually, I like more dynamics, punchy bass and clear, transparent sound.  But the tricky part is, to a point that not to sound fatiguing.  It is more a feeling after a longer time of listening.  When I first hear the Topping dx7 pro, it sounds great.  But after maybe 30 mins, I feel it is too “noisy”, and I need to turn down the volume from my normal listening volume.  I guess this is called the synergy between the components.  I am using a Triode Lab 2A3 and Spatial Lab X5.  Both of them are very revealing.  It seems they match better with the Audio-gd.  I also try the Almarro 318 with the Topping, I don’t feel fatigue.  But I like the Audio-gd + Triode Lab More than Topping + Almarro.  
I think I have two top candidates:

1) MHDT Orchid
this has very good review by reviewer and the community.  People often comment it has a smooth, liquid sound.  
2) Audio-gd R7 or R8
this has rave review in 6moons with a blue moon award.  It is the same brand that I like, and hopefully with similar but improved sound signature.  Also, it is very flexible that I can choose a TDA1541 smoother sound, and NOS vs with over sampling.  

Thanks for all the suggestions.  Some of them haven’t heard before, Will am have a look.

My budget is < $1500.  I am ok to buy used, but those popular ones seems hard to come by.  People are hanging on to them.  =)

I also seriously look into the Audio Mirror Tubadour III.  It has good reviews, and it is from US.  I have bad experience in the Topping DX7 purchase.  So, I am a bit reluctant to buy from China.  I don’t know if the courier services like DHL resumes or not.  Shipping from US is a big plus.