What the Best Dac have you heard or owned. How could you tell it was that good.

I had the factory DAC in my McIntosh C47 preamp and then switched to a PRIMA LUNA 400 preamp with a Bryston BDA-3. Both set ups were very sonically pleasing. My current setup is Backert Labs Rhythm 1.4 and an Aqua Acoustics LaScala DAC. Both are tube based and sound fantastic. Much improvement in the bass and midrange. Please know that if budget is a concern I believe that the BRYSTON BDA-3 DAC is something to seriously audition.

SMSL M400, Topping D90

One thing to keep in mind when evaluating a DAC is that it is hard since it is not the source, the "source" is the combo of network provider, router, switch, cables, digital files, software and maybe DDC and master clock. I have experienced a big jump in performance from a DAC when the whole source chain has been fully optimized. Even "cheap" DACs - say the Gustard R26 - can perform at a surprisingly high level when you fully commit to optimize the entire source chain.

@kairosman great points.  

I have a $80 dongle DAC I tried based on an excellent review with detailed measurements. The numbers said this DAC was a top of the heap performer that outperforms another popular “audiophile” DAC that costs 10k ( also measured by same tester for comparison). I use it only with headphones but based on what I hear I can’t disagree with the rave review. This thing is clean clean clean sounding and nails all the details and dynamics. A real giant killer!

I also have had a Chord Mojo for a number of years. This was also measured and reviewed by same source . Conclusion was the measured performance does not match the hype. I still enjoy the Mojo though It sounds much different than the $80 giant killer. Warmer and smoother but you don’t hear as much detail and dynamics . Very different sounds Which sounds better? You decide. One thing I can say with confidence is that you need not spend a fortune to acquire a top notch DAC these days . 10 years ago the story was different . Technology advances and reproducing even high res music well these days is no longer rocket science. Of course people buy stuff including DACs for many reasons. Measured performance is important to some whereas others rely solely on their ears. It a personal preference thing like always