DAC upgrade suggestion


I am currently using a Audio-gd nfb 3.1.  The information below.  I bought a Topping DX7 pro based on the good data in audio science review.com.  When I first use it, I can hear the difference immediately.  It is more dynamic, bass is more punchy, sound clearer.  It sounds great.  But after listening for a longer time, I feel a bit fatigued.  I can compensate it a bit by switching the tubes in my amp.  Then, I need to return the DX7 because the Bluetooth doesn’t work.  I plug back in the Audio-gd, and i can confirm it is not fatiguing.  It is less dynamic, but also smooth.  Now, I am confused on what I should upgrade.  Several Audio-gd DACs are reviewed by AudioScienceReview.com and the data is very bad, LoL.  I know the bad data doesn’t mean it sound bad, but should I avoid DACs with good data?  How should I pick my next DAC?  It seems R2R DACs maybe a good choice for me since many people says the sound is more analog-like.

http://www.audio-gd.com/Pro/dac/NFB-2/NFB2EN.htm
gte357s
If you want one Dac to enjoy music for a while, rather than churning through experiments, get an Ayre Codex.
R2R DACs are ridiculous - no two resisters are the same in the real world
Ironic given that the resistors on-chip in the ESS DAC in the Codex are far more dissimilar than in any R2R DAC I've seen.
+1 Ayre Codex

Due to system synergy (mine is conrad johnson mf2500 feeding thiel 2.7) YMMV -- after trying PS Audio Directstream Jr, Nad M51, Chord Qutest, etc........ then an Ayre Codex I am done!   I have not tried the R2Rs -- so maybe I am missing something -- but will likely never know.
I to went thru a Audio Science Review phase and started questioning the sound and build quality of my Audio-gd pcm 1704 DAC. I thought there must be something wrong with my ears how could I prefer the sound of this DAC when ASR clearly shows that it has engineering flaws?

First, ASR has never posted a test on a Audio-gd DAC with DSP-1 or FPGA processor(augments the difference in resistor tolerances) as far as I know.

Second, the test they did on Dac 19 DF amirm states he does not know if jumpers are even remotely set right on DF digital filter but proceeds with test anyway.

Third, ASR/amirm list specs for DSP-1 version specs claiming their test on DF clearly shows that Audio-gd does not achieve test specs listed on their site.

ASR/amirm and posters do make some valid points, mains wires and RCA socket wires should be twisted but for the most part IMO they are justifying their purchase on specs alone not sound quality.


All of these posters rave about how superior the R2R DAC's are....yet I suspect none of them have heard Lampizator's  DS53 digital engine, a derivative of the digital engine used in their Pacific DAC. They’ve standardized this Delta-Sigma design throughout their line, and to my ears it's sonically superior to R2R designs.