I have an issue on my Bifrost 2/64 where if I leave and come back hours later the DAC has that terrible sounding compression issue. This does not happen when I'm switching sample rates or in exclusive mode. Only when I leave for a few hours and come back. switching to NOS mode and back to OS fixes it for that entire listening session.
I received the unit last week and assumed it came with lates firmware however just in case I updated it to the latest firmware and the problem still persists. Working with Schiit now.
As far as sound goes, I've had the Bifrost 2 Unison, D90SE, Holo Spring 3 KTE, and a few others. This 2/64 is a massive upgrade from the previous Bifrost in my opinion. The previous version was good, but to my ears the 2/64 is a TRUE middle ground between full R2R and Delta Sigma options. and for many I can see this being end game.
Comparisons (I am terrible at this, but I will try my best)
These are all using an iFi iCAN pro signature amp with HE1000SE headphones mainly. I have used other headphones, but the comparisons were used with 1000SE
Comparing the Holo Spring 3 and the 2/64 - This probably is not a fair comparison, but i was actually impressed how the 2/64 stood its ground against the spring 3. There is slightly more treble energy in the 2/64 but the spring 3 is superior when it comes to treble control and tonality. The spring 3 has better weight with its notes and reaches further down into sub bass, has better sound stage and imaging but has a more relaxed nature. The 2/64 has a way of showing you micro details with a slightly more in your face presentation to the natural presentation of the spring 3. Both are good at depth in the soundstage but the spring 3 presents everything with a natural holographic stage. the 2/64 has good separation but less space in between instruments. There were some songs i preferred the dynamics from the Bifrost especially with electronic/bass music.
Bifrost 2 Unison vs 2/64 - In my opinion the 2/64 version is just better at everything than the old version. More space, More dynamic, more depth, better subbass and texture. the 64 does have a slightly more thin mid range when compared to the older Bifrost 2. With the old version things could sound a bit too warm. (To some this may be a benefit) The new version still has a slight warm tilt but not to the extent of the Bifrost 2 unison. I could see some people liking the old version if they have a very bright chain.
D90SE VS 2/64 - this is an easy one if you like pure resolution and a very intimate presentation the D90SE is for you. It is more resolving than the 2/64 but the tradeoff is everything sounded very digital to me on the D90. The 2/64 has way better stage size/depth and way better subbass performance and a more organic signature.
EF400 VS 2/64 - Let me preface this one by saying that i think the EF-400 is very good value for the money considering its a dac/amp for less than the Bifrost, but just in case anyone was wondering.... i hooked it up to the iCAN pro via SE output to use just the DAC stage. Well...... the Bifrost is better in every single way EXCEPT the HE400 is just super smooth. I would only prefer the EF-400 if I was listening to like Lo-Fi study music. The Bifrost is in a completely different league here.
Sorry if my ramblings make no sense this is just my opinion but i am impressed with the 2/64 version. one of the best DACS I've heard sub $1,500