Here’s some initial thoughts/comments on the changes at work here. It’s a bit difficult to know where to start with all these upgrades and changes … so don’t consider the following list as being in any kind of “order of importance”:
All-new DAC & Analog Stages
Bifrost 2 uses instrumentation DAC chips that belong to the same family as Gungnir MB and Yggdrasil. And they’re 18-bit converters (as with Gungnir MB) vs. the 16-bit units used in the original Bifrost.
And there’s a new analog stage to feed both the balanced and single-ended outputs, and they measure very closely.
Balanced (XLR) Output (and single-ended via RCA)
Anyone that’s spent any time in threads about either Bifrost or Jotunheim, or especially the big “Schiit Happened: The Story of the World’s Most Improbable Start-Up” thread, will have seen myriad requests for a balanced-output version of Bifrost. This has been a natural, and increasingly pent-up, desire ever since the launch of Jotunheim.
Now it’s a reality, and you can pair Bifrost 2 with Jotunheim and have a fully balanced chain from end-to-end, or run it in a form-factor matching stack with the other Schiit amps with the balanced option available as/if/when you need it.
Better yet, there’s virtually no difference* between XLR and RCA outputs, so you can use it in either configuration, now, or as the rest of your rig evolves, without penalty for switching how you connect it.
This is an all-new, completely in-house, USB implementation**. Gone are the CotS USB receivers and decoders. This runs custom code on a PIC32 microcontroller. And that provides many options for implementation and processing not available with off-the-shelf chipsets.
Oh, and it is electrostatically and electromagnetically isolated, which means far less potential for noisy USB-sources to cause downstream issues. No more need for things like “Eitr” (which is, probably not coincidentally, now in “end of life” status).
The original Bifrost, which was Schiit’s first DAC, was also upgradeable. In fact it has had more upgrades offered for it over it’s lifetime than any other Schiit product:
Starting at launch, you could save some money by ordering a unit that didn’t have a USB input. And if you wanted one later on, it was an upgrade option. Later on an improved USB board was offered, “USB Gen 2”, and most recently “USB Gen 5”.
Upgrades to the DAC/analog board were also offered. First with the “Uber” card which offered a substantially improved analog stage, followed by the “4490” which was a new converter and analog stage, and finally the Multi-bit board which was my favorite of the iterations.
Note that you can still buy the “USB Gen 5”, “4490” and Multi-bit upgrades for the original Bifrost if you so desire.
Of course the question arises - if Bifrost was upgradeable, why come out with an all-new iteration and not just upgrade the old one?
Two major reasons I see for this, speaking as a former owner of the original:
The new features go beyond what would have been possible with the older model. For example, there’s nowhere to squeeze in XLR outputs, nor do remote control, without having a completely new chassis.
The original was something of a pain in the arse to upgrade.
If you braved the self-install, which most people didn’t, it was a lot of screws and a fiddly reassembly process (the LEDs were always a joy to get realigned with the holes in the front panel). And if you sent it in to have Schiit do it, you were without your DAC for some period and it was more expensive to do. Oh, and firmware updates, which were required for the multi-bit upgrade, HAD to be done at the factory.
The new upgradeable architecture is called “Autonomy” … because you can do all of the upgrades yourself - quickly and easily. No more shipping the thing off to Schiit.
Here, firmware is updated via microSD card slot on the rear of the unit. You can download updated firmware, copy it to a card, and do this yourself easily. And for “needed” updates (or the technologically ham-fisted) Schiit can even send you a card with the image already there to make it even easier.
And swapping either the USB card, or the DAC/analog card, now requires nothing more than undoing a couple of screws, sliding the old one out, slide the new one it, put the two screws back and bingo!
This is another thing that’s been asked for a lot, particularly from people not using this as a desktop-only unit. You can still switch inputs from the front-panel, but now you can do it remotely too. And you also gain phase-inversion, which is useful for some recordings, and was previously only available on Yggdrasil (in Schiit’s line-up). There’s a handy mute-function too … again probably more useful from those not sitting and listening at a desk.
You can find more details and rationale for all of these changes in the Bifrost 2 FAQ.
Proper impressions and so on, as well as a review, will follow as I get to spend some proper time listening to the new unit. I’ve only had this in my hands for about 2/3rds of a day so far!
*Based on the measurements posted. I have not yet had the unit long enough to compare outputs from a listening perspective.
**Unison USB upgrades will also become available for some other Schiit upgradeable DACs.