AudioQuest Dragonfly Cobalt

AudioQuest Dragonfly Cobalt

It’s hard to believe that it has been eight years since the release of Audioquest’s ingenious Dragonfly, the memory stick-sized USB DAC/preamp/headphone amp that provides a simple, effective and affordable solution to the problem of mediocre sound quality from computers.

The original Dragonfly was supplanted in 2016 by two new models; the even more affordable Dragonfly Black, and the more expensive but also more powerful Dragonfly Red.

Both featured redesigned USB controllers that drew a fraction of the current and made them compatible with not just laptops but also tablets and smartphones and, with two prices of admission, brought high quality sound to an even wider audience.

Measuring just 57mm long (2 ¼”), the svelte new model is 10% smaller than its siblings and its streamlined profile and immaculate deep blue finish is more reminiscent of a finely polished jewel than a USB dongle.

While its size may have shrunk, Cobalt’s internals certainly hasn’t been scrimped on. It sports the latest ES9038Q2M DAC chip from ESS that – like the ESS 9016 chip used in Red – has been implemented with a minimum-phase reconstruction filter.

Unlike Red’s minimum-phase filter, however, AQ has chosen to roll-off ultrasonic frequencies less steeply in Cobalt to provide a “more natural sound”.

The new ’Fly retains Red’s ESS Sabre9601 amplifier output stage, but AQ has treated it to a new USB microcontroller, the Microchip PIC32MX274, which draws even less current and apparently increases processing speed by a third.

Like previous models, Cobalt uses Gordon Rankin’s StreamLength asynchronous-transfer USB code.

Its monoclock technology has a single, ultra-low jitter clock generated from the DAC chip that runs the ESS chip functions as well as all microcontroller functions.

The built-in power supply filtering has also been upgraded, improving electrical noise rejection from wifi, Bluetooth and mobile phone signals to allow Cobalt to reach its full sonic potential.

Cobalt supports native PCM sampling rates up to 96kHz at 24-bits and the Audioquest Dragonfly Cobalt USB logo illuminates accordingly to indicate the sampling rate of the file being played.

It cleverly glows green for 44.1kHz content, blue for 48kHz, yellow for 88.2kHz, light blue for 96kHz and purple for MQA (note that Cobalt is an MQA renderer only and must be used with a player that can unfold MQA files).

DSD is not supported natively so you need to configure the player to resample it to 88.2kHz PCM to preserve as much of the format’s qualities as possible.

Audioquest Dragonfly Cobalt USB is compatible with Apple and Windows computers, iOS and Android devices. Its bundled accessories include an engraved black leather storage pouch and a DragonTail USB adaptor, a short length of AQ Carbon USB cable that facilitates device connectivity whilst relieving port strain.

AQ offers three DragonTail configurations: female USB-A to male USB-A, female USB-A to male microUSB/OTG, and female USB-A to male USB-C.

While the new iPad Pro features a USB-C port and can tethered using the included DragonTail, owners of Apple devices with Lightning ports must purchase either Apple’s Lightning-to-USB adaptor or the larger and more expensive Apple Lightning-to-USB 3 camera kit adaptor.

AQ recommends the latter for superior sound quality and reliability.

Like its 3.5mm TRS output-equipped Black and Red Dragonfly siblings, Audioquest Dragonfly Cobalt USB can be used as a standalone DAC or as a DAC/preamp into headphones.

It has a low-noise, 64-step bit-perfect digital volume control that can be controlled through either your source’s operating system or, where permitted, directly from within your preferred music player.

When connected to a >10kΩ load such as an external preamp, power amp or active loudspeakers, Audioquest Dragonfly Cobalt USB outputs a maximum of 2.1Vrms, comparable to many other line level sources.

Despite an output impedance of just 0.65Ω, normally low enough for efficient power transfer and linear frequency response delivery into all but the most punishing of headphone loads, Audioquest Dragonfly Cobalt USB maximum output voltage before clipping drops quite early on as load impedance decreases due to the output stage’s finite current supply.

Unofficial measurements suggest Audioquest Dragonfly Cobalt USB clipping point is -3dBFS with 300Ω ‘phones and -6dBFS with 30Ω ‘phones, output voltages of around 1.6Vrms and 1.05Vrms respectively.

AQ recommends using headphones with an impedance no lower than 16Ω. Low impedance headphones tend to have higher voltage sensitivity and so usually require less output voltage than high impedance models to produce the same volume.

The reduction in output voltage as load impedance decreases is therefore more likely to be an issue on the rarer occasions that Cobalt is paired with a low impedance headphone that also happens to have low sensitivity.

After putting the Audioquest Dragonfly Cobalt USB through its paces with headphones from 32Ω to 600Ω. As an over-ear headphones only listener I was unable to test the quietness of Cobalt’s residual noise floor with earbuds.

In both environments, AQ’s latest Dragonfly belies its tiny size and delivers a bold sound that is brimming with punch and detail.

While both Black and especially Red already provide important steps up in quality from laptops’ and smartphones’ own headphone outputs, Cobalt widens the gulf further.

As excellent as its Red sibling is, it’s fair to say it is not always consistent in its delivery of bass and treble frequencies, which can be a little fuzzy and/or disjointed in places.

The Audioquest Dragonfly Cobalt USB strips away this imprecision and presents a clearer and more cohesive image with seamless transitions between low, middle and high frequencies.

Rhythm and timing are also improved; instrument fundamentals and overtones not only have more wholesome timbres but are also in closer lockstep and land with greater speed and impact.

Despite replacing a Schiit Yggdrasil that costs almost ten times as much and commandeers an entire shelf in the rack, the little blue Dragonfly did not embarrass itself.

It may not be as nuanced as Yggdrasil, but its confident expression goes a long way to make up for what is otherwise lacking from the soundscape.

The book-sized Audioquest Dragonfly Cobalt USB, multi-input irDAC-II admittedly uses the much older ESS 9016 DAC chip, but I still find it remarkable that a comparable level of performance can now be obtained from a USB-powered dongle that isn’t much bigger in size than the DAC chip itself.

Scaleability:
Because a chain is only as strong as its weakest link, matching headphones to a source that’s a fraction of the price is an approach that is often frowned upon. It is however precisely for this reason, as a reviewer, that I make such pairings.

High-end headphones can be extremely revealing of deficiencies upstream and therefore tell you a lot about the quality of the source.

If there is any glare or edginess present in the treble response, for example, then headphones like the Audio-Technica ATH-ADX5000 or Sennheiser HD800S are sure to find it.

Specifications of the Audioquest Dragonfly Cobalt USB:
Type: USB DAC, preamp, headphone amp
Sample rates (LED indicator color code): Standby (Red), 44.1kHz (Green), 48kHz (Blue), 88.2kHz (Yellow), 96kHz (Light Blue), MQA (Purple)
Volume Control: 64-position 64-bit bit-perfect
Output Voltage: 2.1 Vrms max
Headphone Amp: ESS Sabre 9601
DAC Chip: ESS ES9038Q2M with minimum-phase slow roll-off filter
Microcontroller: Microchip PIC32MX274
Dimensions (LxWxH): 57mm x 19mm x 12mm
Weight: 17g