Temperature concerns aside (I’m sure it’s fine, I’ve just never had an R2R DAC before) my impressions of this DAC might help to inform some people’s purchase, so here goes:
My headphone ownership history (over the last 10 years or so): Sennheiser HD590, ATH-M50x, Grado SR80e, Sennheiser HD58X, Beyerdynamic DT-770 Pro, Beyerdynamic DT1990 Pro, E-Mu Teak, Audeze LCD-X, Hifiman Arya, ZMF Aeolus.
My equipment history goes something like this: My DAC/Amp progression has gone from using nothing but PC hardware, to using a Fiio E10k, then to using various iterations of the Modi/Magni stack, then to a THX 789 which most recently I’ve paired with the Modius. I have a GS-X Mini on the way which I see very much as my final destination Amp-wise. The Bifrost 2 I expected to be a step up from the Modius, and I’m sure that for some people it is, but my impressions are as follows.
Upon unboxing the Bifrost 2 and plugging it in, I initially felt that it sounded fractionally warmer and fuller in the low end than the Modius, but ever so slightly lacked the same levels of detail retrieval across the full range. I also perceived a slightly reduced sound stage. I wrote all of this off as me not having given the Bifrost time to warm up, as many often report that DACs like this can take a bit of time to reach their full potential.
Fast forward 24 hours, and I decided to A/B test the Bifrost 2 against the Modius by running XLR cables from both, and just swapping the inputs on the THX 789. I made up a list of songs, and I’d listen to each song twice, first on one DAC and then on the other. The entire process took about 3 to 4 hours. In my personal experience, the two DACs sounded more or less exactly the same. Every time I thought I perceived a difference with a particular part of a particular song, I’d pause, swap the inputs, and do a direct comparison, and every time I’d come to the conclusion that there actually wasn’t a difference. I’ll say it again - they sounded the same. 99% identical. Any difference was so subtle that I could genuinely write it off as being my imagination, and if you were to put a blindfold on me, I wouldn’t be able to tell which was which.
Fast forward another 24 hours, I repeated the experiment. No playlist this time, just randomly choosing songs and comparing DACs, sometimes full songs, sometimes sections of songs that I felt represented a diverse set of scenarios. By the end of this session (perhaps another two hours) I came away with slightly different impressions. My overriding feeling is still that these DACs sound more or less the same, but there are very, very subtle differences. The Bifrost 2 feels ever-so-slightly warmer than the Modius, and ever so slightly more ‘full’ in the lower frequencies, whereas the Modius feels fractionally more analytical and detailed. There is a sense of depth to the Bifrost which the Modius challenges with a touch of extra precision in the treble. Beyond that, I have to reiterate yet again - if you blindfolded me and asked me which is which, I would not be able to tell you.
So for me, personally, the Modius seems to represent extraordinary value at $200 considering that I couldn’t separate it from a $700 Bifrost 2. It also has taught me an important lesson about just how subjective the pursuit of the audiophile can be, as I wouldn’t dream of saying that another person couldn’t come along and come to a completely different conclusion about the differences between these two - I’m certain that there are those amongst you for whom the fractional warmth and fullness that I perceived would not only seem like a far more significant differential, but well worth the extra $500.
It makes me think of wine - someone who doesn’t drink a lot of wine isn’t going to be able to make any sense of why one bottle might cost $10, and another might cost $50. That person could taste both, perceive a difference between them, but wouldn’t necessarily agree that those differences are worth $40. Conversely, some people develop an appreciation of wine over time which allows them to understand the differences between those two bottles, and to them the $40 difference would be justified. It’s all subjective.
To me, the differences between these two DACs are almost imperceptible, and I don’t see the $500 difference as being worth it due to the existence of the Modius. This is all just my personal experience, and if you own a Bifrost and love it, that’s awesome. If, however, you’re a person who’s looking to step up from a cheaper DAC with the expectation of significant, noticeable differences that are proportionate to the extra expense, for me personally, you’re 95% of the way there with a Modius, and every percentage point above that is potentially subjective and undeniably expensive.