USB DAC Test
The set up is as follow:
- Transport: PowerBook G4, Itunes, Lossless files
- DAC (USB input): The respective players
- Amplifier: Beta22, or the built in player
- Headphone: Sennheiser HD800
As a USB DAC, most of the players suffer some loss of quality. Most noticeable is the degradation of the HM-801, where it was ranked no.1, but as a USB DAC, it suddenly slides down to the bottom of the pack. Soundstage and detail levels suffers tremendously, and you can forget about the great ambiance that it had before. At that configuration, the HM-801 is just a hair better than the QLS, where it remains superior on soundstage depth and separation. But soundstage width becomes much smaller than the QLS, and some people would even prefer the QLS to the HM-801 on this level.
The HM-602 doesn’t suffer as bad as the bigger brother, still maintaining a lot of its great qualities in the sound and with only a slight loss of quality. More or less you’re still getting the same sound signature, soundstage performance, but with a slight loss of refinement. As a matter of fact, the HM-602 is only second to the HRT MS2+, which is a dedicated build USB DAC. Not bad at all! For day to day listening sessions, the degradation of the USB function is probably not going to be noticeable.
The Ibasso DB1+PB1 on USB suffers quite a bit, though not as much as the HM-801, but more than the HM-602. This places the DB1+PB1 below the HM-602 as a USB DAC.
To recap the results of the test, here is the list that I created, sorted according to the sonic performance and nothing else. I added some comments such as soundstage size, depth, micro details, etc. In my experience, a good soundstage depth is far harder to achieve than a wide soundstage. Hence I will rank a source with better depth even if the width is narrower than the source below it. Likewise things like micro details and ambiance, though very subtle, is also harder to achieve than soundstage width, so the same logic applies to the ranking.
- Hifiman 801 DAP = Detail, ambience, bass, depth, separation
- Ibasso DB1+PB1 Coax = Soundstage slightly more narrow than HRT, but more refined, little details, depth, separation
- HM602 DAP = Soundstage slightly more narrow than Ibasso DB1+PB1 Coax, but still very good micro details, depth, separation better than HRT2
- HRT MS2+ USB = Very good overall. Widest soundstage (even wider than HM801), but micro details, depth, separation is not as good as the three above it.
- HM602 USB DAC = slight downgrade than the DAP version, loses a little bit of refinement.
- Ibasso DB1+PB1 USB = also downgraded, and more than the HM602 this time
- QLS QA350 = wide soundstage, good separation, but lacks depth and micro details
- HM801 USB DAC = soundstage and detail suffers a lot, but still maintains separation and depth.
Frankly I’m impressed with two things. First is the quality of the HM-801 source. Though it was no.1 in my last DAP comparison, I was comparing it with “mainstream” products. This time the competition is much tougher, and yet the HM-801 maintains quite a big gap in sonic performance to the second in line: the DB1+PB1. I really would consider using the HM-801 as a desktop source, perhaps as an office rig, as you practically don’t need any other amp for most headphones. The second thing that impresses me is how the newer, smaller, lighter, and cheaper HM-602 DAP gives such a good performance in the midst of all the other players. From a practical standpoint, I don’t think it gets any better than the HM-602. The thing is lighter than my Ipod Classic, and yet it gives an outstanding sound quality with a signature that’s even more likeable than the bigger brother.
Other than that, I think the Ibasso concept is quite interesting, but I probably be sticking to just the Toucan amp and skipping the Boomslang DAC, as three packs are just too much for me.