I’ve been getting several questions about what the Singxer SU-2 DDC does for the Schiit Bifrost 2 DAC. In my Bifrost 2 review I mentioned that it sounds best from its USB input, despite it having both coaxial and optical SPDIF inputs. This is due in large part to the quality of Schiit’s Unison USB implementation. Unison is Schiit’s in-house USB solution that cleans up some connection issues. The BF2 is the least expensive model in Schiit’s DAC lineup to include galvanic isolation with Unison USB. After my comments above stating what I heard the SU-2 do for the Chord Hugo 2, I got several questions about what might happen if I used the SU-2 with the Bifrost 2. So today, I sat down and did just that. Here’s what I found…
Test Gear
I used the Monolith Liquid Platinum (MLP) and Bottlehead Crack + Speedball (BHC; review in the works!) as the amps and used the Focal Radiance (review pending for this too!), Audeze LCD-2 prefazor revision 1, Drop + Sennheiser HD6XX, and Beyerdynamic DT880 600Ω as the headphones. I did not use my more expensive gear because I thought this test would be most useful using all mid-fi gear, as those who own and use the Bifrost 2 will most likely have other gear around that same level of technical ability; it seems the most real-world to me, anyway. The MLP was connected to the BF2 via XLR and the BHC via single-ended RCA cables. The SU-2 was connected to the coaxial spdif input of the BF2 via a basic Monoprice 75Ω coax cable and both the SU-2 and the BF2’s USB input were connected to my PC via identical and basic Monoprice USB cables.
Findings
In general, the SU-2 is a marginal technical upgrade over Unison USB. The soundstage sounds more open. This is not to say the soundstage is bigger, but there is a feeling of space beyond the soundstage that is more present with the SU-2 in the chain than just straight to Unison USB. To my ear, the left-center and right-center sonic images were also slightly more fleshed out and believable with the SU-2. The SU-2 brought out more microdetail. Even though everything was inherently volume matched because the same DAC was used and the same amp was used, I kept wanting to turn up the volume when Unison was in use. This is likely because the SU-2 was helping resolve more fine detail that was missing with Unison. The SU-2 also brought more slam and macrodynamic impact, with a more convincing representation of speed and quickness. Finally, this test gave me a better understanding of the term “tonal density”. With the SU-2, individual tones and sounds had a fuller, weightier sound to them. They didn’t sound bloated or overdone, it was more of a sense of tonal completeness than Unison was able to convey.
The above paragraph likely sounds like a blowout in the SU-2’s favor. I did not find that to be the case. The differences are always subtle. To my ear, the Radiance from the balanced headphone output of the MLP resolved these differences the most starkly. The LCD-2 from the same amp much less so. The 6XX from the BHC was probably just behind MLP + Radiance. The DT880 + BHC was probably somewhere between the LCD-2 and 6XX. The LCD-2 is a more relaxed headphone to begin with, so I suspect that is why it was most difficult to hear the differences there, though they were present. But, regardless of pairing, the differences are small. The magnitude of change is certainly less than what the SU-2 and Hugo 2 did together.
Is SU-2 Worth It For BF2?
Ugh, the question of ‘worth it?’ is so tough. There is no universal answer. If I had to my system building to do all over again and was using the BF2 as my primary DAC, knowing what I know now I would save the $429 MSRP of the SU-2, save a little longer, and look for a used Yggdrasil. A used Yggy can be found in the $1.6k-1.8k range typically. I think the jump from the $700 BF2 to that price point is larger than the jump from the $1129 total of BF2 + SU-2. However, if you have BF2 and a good deal on a used SU-2 comes along, it’s not a bad option. It is an upgrade and will pay even bigger dividends down the line if you choose to make the jump up to the next tier of DACs.
OK, I hope this helps those of you who were dying of curiosity about SU-2 + BF2. Cheers, all. Enjoy the music!