AUDIOQUEST DRAGONFLY COBALT PORTABLE DAC
Portable DaC/HeaDPHone amPlifier
No longer do you have to suffer poor audio quality when travelling. Steven Dawson looks at the new Dragonfly Cobalt.
These days, just because you’re travelling does not mean you have to settle for second-rate sound quality. You can listen to high-quality music from your notebook computer, iPhone or Android phone without making do with mere Bluetooth connectivity, even if your device doesn’t have a headphone output. All those devices support an external DAC. And that’s where the AudioQuest DragonFly Cobalt comes in. It is a super-compact DAC and headphone amplifier you can take with you when you’re travelling.
The equipmenT
The Cobalt is the latest and most premium version AudioQuest’s DragonFly series of DACs. It looks somewhat like a USB memory stick, around the same length and volume as a typical mid-sized one. But it looks much classier than that, with its deep, glossy cobalt blue finish and backlit DragonFly logo. At one end is a standard USB Type-A plug suitable for plugging into the matching socket installed on most PCs. That’s both Windows and Macs and, I’d wager, Linux, although I haven’t tried it on one of those.
At the other end is a 3.5mm stereo socket. That’s suitable for driving headphones and also delivering a line-out signal for external equipment. As we’ll see, it most certainly delivers high-fidelity performance. In between the two is a great deal of advanced electronics, to which I’ll return shortly.
The Cobalt comes with a cap to cover the USB end. The cap is similarly finished. It also comes with a tight-fitting leatherette pouch and an adaptor cable. That last is a departure from the DragonFly norm. The cable has a USB Type-A socket on one end and a USB Type-C plug on the other. The Type-A end is shaped to conform to the lines of the Cobalt. The Type-C adaptor recognises the reality that many high-end notebook computers and Android phones—and indeed, now, the iPad Pro—use USB Type-C. (iPhones? Rumours persist that Apple may eventually switch the iPhone over, but equally strong arguments suggest not.)
For those amongst us who may not be familiar with this stuff, the USB Type-C connector is far smaller than the standard computer-style USB Type-A, but larger than the Micro-B USB connector frequently used with Android phones. But it’s far easier to plug in than either, and can be inserted either way. It can support the latest versions of USB for fast data transfers, and is also used for Thunderbolt connections.
The Cobalt does not replace AudioQuest’s existing DragonFly models, the Black and the Red. It’s for those who want higher performance and are prepared to pay a 40 per cent premium over the Red.
Apart from a slightly different shape, the inclusion of the adaptor cable and the colour, the main differences to the Red are the DAC chip and microcontroller. The latter increases processing speed and uses less power. Since the Cobalt will mostly be used with portable devices, that’s good news. The Cobalt switches from Red’s ES9016 DAC chip to the ES9038Q2M, ESS’s top-of-the-line DAC for portable applications. The ES9038Q2M has a choice of filter slopes available.
AudioQuest has chosen the Minimum Phase Slow Rolloff option of that filter. AudioQuest says that this filter choice: ‘ results in naturally expressive sound that is always emotionally engaging and never fatiguing—a beautiful combination of warmth and detail that we find equally exciting and soothing.’
The ES9038Q2M has a rather intimidating set of specifications, with THD plus noise at –120dB, 32-bit signal handling, support for up to 768kHz PCM and DSD1024, and the production of an ultra-low jitter clock signal. The Cobalt uses that clock to run the microcontroller functions.
The output from the ES9038Q2M is fed into the same ESS Sabre 9601 headphone amplifier used in the Red. This is also a very high-performance model, with up to 2.1 volts output and THD+N at –117dB.
There is no physical volume control in the sense of a knob. But there is an internal 64-position analogue volume control which is software controlled. That is, properly operating player software ought to send signals to adjust the control. That avoids digitally resampling the audio, which would introduce errors.
The light behind the DragonFly logo changes colour to indicate the signal the DAC is receiving: 44.1kHz, 48kHz, 88.2kHz or 96kHz. Or MQA. The DAC supports MQA, although it’s not entirely clear to what extent. That’s another thing I’ll return to.
Now, I had trouble working out what the colours actually indicated. The information in the manual was misleading, as was the FAQ on AudioQuest’s website. They said green for 44.1kHz, blue for 48kHz, amber for 88.2kHz, magenta for 96kHz and purple for MQA. The first two were right and the last were wrong. As another place on the website, and the real world in the form of my tests, revealed, yellow is the colour for 88.2kHz, and white (the website calls it light blue) is the colour for 96kHz.
As I often dwell upon in these reviews, a positive visual indication by a DAC of the signal it is receiving is important. I for one don’t trust my ability to tell the difference between, say, the original bitperfect 96kHz audio of a high-res track, and a version downsampled by the operating system to 48kHz. More to the point, I waste valuable listening energy wondering the moment I hear any possible defect, and without a way to be certain of what might be causing it, the listening experience becomes rather less satisfying.
With the Cobalt, I see the DragonFly light up white (very light blue, if you must) and relax, confident that I am hearing things as they ought to be.
You will note that there are no indicator lights for, say, 176.4kHz or 192kHz sampled tracks. That’s because the AudioQuest DragonFly Cobalt does not support sampling rates higher than 96kHz. Nor does it support DSD. Yes, the ESS DAC can go to 768kHz and DSD1024, but AudioQuest has implemented the Cobalt, like its other models, as a USB Audio Class 1.0 device, not USB Audio Class 2.0. That way it plays without the need for drivers even on Windows 7 and 8.
A lot of player software will notice this and automatically convert 192kHz to 96kHz and 176.2kHz to 88.2kHz. Nonetheless, now that Windows 10 natively supports USB Class 2.0 Audio, perhaps it’s time for AudioQuest to switch over.
InstallatIon
On attaching the Cobalt to my Windows computer, it quickly installed and became the default playback speaker. Since no drivers were needed, installation was certainly easier than most. It selected 24-bit/48kHz as the output standard, but 24-bit/44.1kHz and 24-bit/96kHz were also available. If you’re just planning on using Windows standard Direct Sound output for playing CDs, then it would be a good idea to pop into the settings and change it to 24/44.1kHz output to avoid unnecessary, and resolution-fuzzing, resampling. (In Windows 10, start typing ‘Sound Control Panel’ into the search box until it appears at the top of the list, click on it, select AudioQuest DragonFly Cobalt and click Properties, go to the Advanced tab.)
But, of course, not everyone uses Windows computers. So I plugged it into my Mac Mini. The Cobalt didn’t automatically become the default output (Macs don’t do that), but it offered the same range of output settings as for Windows.
I used the included adaptor cable to plug the DAC into the USB Type-C socket of my Huawei P30 Pro phone. One of my phone’s music player apps fired up and asked if I wanted it to open automatically when the DAC was attached. It happily played music to the Cobalt.
Finally, I used an Apple Camera adaptor to plug the Cobalt into my 2018 iPad. (Yes, it’s still called a camera adaptor, even though it’s actually a more general USB breakout gadget.) I initially used my ancient one designed for the long-obsolete 30-pin Apple connector, combined with a Lightning to 30-pin adaptor. But after a while I decided to update to a modern USB 3.0 adaptor. Both seemed to work equally well, although I note that AudioQuest says that there have been reports of spurious noise with the still-current non-USB 3.0 Lightning adaptor.
All of which is to say: it doesn’t really matter which portable platform you are using—the AudioQuest DragonFly Cobalt will work with it.
In Use and Performance
I did most of my listening using three sets of ear gear. First was a pair of Focal Elear open-backed headphones. Second was a pair of Oppo PM-3 planar magnetic closed-back headphones. Third was a pair of Final Audio B3 in-ear monitors.
The first thing to note was that the performance was entirely at odds with visual impressions. I have reviewed large, heavy multi-thousand dollar DACs. This thing is light—less than twenty grams—and small (19×12×58mm—HWD). I felt a psychological predisposition to think that the sound it could produce must likewise be light… and small. Surely it must be, in some way, less than those others?
Um, wrong. With track after track, album after album, the closed-eye sense was one of unlimited, ‘large’ if you like, authority. It’s almost a weird experience, the mismatch between the 19 gram gizmo and the sound it made the headphones deliver, especially with the Focal Elears.
Track after track, album after album, the closed-eye sense was one of unlimited, ‘large’ if you like, authority. It’s almost a weird experience
Indeed, as I am typing this I am streaming ‘Primus & the Chocolate Factory with the Fungi Ensemble’ from Tidal (at CD quality using the Mac). The DragonFly logo is lit green indicating 44.1kHz sampling, the Tidal volume control is set at around 50 per cent, and the sound is powerful and detailed with seemingly limitless bass extension. The kick drum is delivered with every nuance of atmosphere. The congas, back in the mix, sit in space easily picked out, with the sound of skin on skin fully realised.
What about MQa?
So, what about MQA? Well, things were tricky there. I played a lot of stuff from various sources looking for that purple backlight which indicates Master Quality Audio. My understanding is that the indicator shows whenever MQA is detected. But there are two things that MQA does: one is fold higher resolutions into lower ones to achieve compact files sizes. The other is to certify that the studio or producers are happy with the final result. The MQA indicator in the Cobalt doesn’t seem to distinguish between the two, and whether it works at all depends on your platform, your software and its settings.
I have a bunch of MQA test tracks. I started with the Android phone. The USB Audio Pro app fed the MQA tracks from my network server to the DAC, and it satisfyingly lit its logo purple. MQA received!
So then I went to Windows. I set everything I could find in JRiver Media Center to straight bitstream, but the light resolutely remained green (44.1kHz) or blue (48kHz).
Mac? Same thing. But perhaps that was because I was using an older version of Audirvana Plus. The iPad? I used the Onkyo HF player with the paid high-resolution upgrade. The light on the Cobalt responded appropriately to the 44.1kHz, 48kHz, 88.2kHz and 96kHz test tracks. But not the MQA test tracks. For those it remained green for 44.1kHz.
Well, one thing we do know about MQA is that the TIDAL online streaming service offers a fair bit of MQA material… if you are subscribed at the $24 per month level. My subscription was the regular $12 per month level, so I upgraded. I tested with another DAC I know to be MQA-capable and which gives a clear indication of its status. Then switched to the Cobalt. I had to fiddle with the settings in the Windows TIDAL app for a bit before I was rewarded with the purple DragonFly.
If you’re doing the same, the trick is to make sure ‘Use Exclusive Mode’ is selected, and that ‘Passthrough MQA’ isn’t.
With my other DAC, I had to have ‘Passthrough MQA’ switched on to make it work properly, but not with this one.
When I was searching TIDAL for MQA material I stumbled across an amazing album called ‘Fairytales’ by Steve Dobrogosz and Radka Toneff. It dates back to 1986, but could have been recorded yesterday. Her voice was simply glorious, both through the Focal headphones and the Final buds. What was particularly impressive was the piano, which was imparted with a sense of, well, authenticity… of reality… of presence.
When I played this on my other DAC, the Blue MQA indicator lit up, indicating studio authentication, while the sampling indicator showed 192kHz sampling. Remember, MQA folds high-resolution audio down into a 44.1kHz or 48kHz sampling space. When I played this to the Cobalt with ‘Passthrough MQA’ switched on, the Dragonfly lit blue, indicating 48kHz sampling. I must assume that in the absence of the purple logo there was no unfolding going on. Even with that switched off, so the logo becomes purple, it’s unclear what’s going on. Is the TIDAL app unfolding the audio to 96kHz? Is the DragonFly Cobalt further unfolding it internally to 192kHz? Even though the DAC interface is limited to 96kHz, it’s far more capable internally. Irrespective, the sound was glorious.
One more point on MQA, I also tried Beyonce’s 2016 album ‘Lemonade’.
Particularly impressive was the piano, which was imparted with a sense of, well, authenticity…