Best USB DAC Dongles Compared: DragonFly Cobalt, Fosi Audio DS1 and Hidizs S9 Pro

Introduction

A dongle DAC is one of the simplest upgrades available for a laptop or a phone. It bypasses the built-in audio output, converts digital files to analogue with a dedicated chip, and feeds headphones through a small amplifier. The category now spans an enormous price range, which makes choosing harder than it should be.

At the top of this group sits the AudioQuest DragonFly Cobalt, a flagship dongle DAC priced at around $350. At the other end is the Fosi Audio DS1 at around $77, which still manages to offer balanced outputs and an onboard volume control. Between them sit the DragonFly Red at around $200, the DragonFly Black at around $100, and the Hidizs S9 Pro.

What makes the comparison genuinely interesting is that the Cobalt, the Fosi Audio DS1 and the Hidizs S9 Pro all use the same ESS Saber 9038Q2M DAC chip, yet they do not sound alike at all. A shared chip sets a baseline for resolution, not a verdict on character.

That gap between specification and sound is the reason this guide focuses on listening character, connection options and build quality as much as on the chip inside. Each of the five models below occupies a distinct position, and the right one depends on what you are plugging in and what you are listening to.

How These Dongle DACs Were Compared

Five practical factors separate these models from one another.

The first is the DAC chip. The Cobalt, the Fosi Audio DS1 and the Hidizs S9 Pro share the ESS Saber 9038Q2M. That makes their differences a matter of tuning and output stage rather than raw conversion hardware.

The second is output configuration. The Cobalt offers a single 3.5 mm output, while the Fosi Audio DS1 and the Hidizs S9 Pro both provide balanced and single-ended connections.

The third is volume control. The Cobalt has a fixed output, so level is set on the source device. The Fosi Audio DS1 has its own volume control on the unit, which lets you max out the digital source and adjust level in the analogue stage.

The fourth is connectivity. The Cobalt uses a USB-A plug that goes directly into the host device, with a short USB-A to USB-C cable available for newer ports. The Fosi Audio DS1 uses a USB-C input and ships with a cable. On an iPhone, the Cobalt needs the Lightning to camera adapter rather than the Lightning to USB adapter.

The fifth is build and price, and here the spread is widest of all.

Listening was done with three sets of headphones: the HiFiMan Edition XS, the Meze 109, and the Drop Sennheiser HD 6xx. The HD 6xx is a genuinely hard load for a dongle, and both the Cobalt and the DS1 drove the Edition XS comfortably. The HD 6xx is a tougher ask, and there are better-matched options for it, but either dongle remains usable with it.

AudioQuest DragonFly Cobalt

The DragonFly Cobalt is AudioQuest’s top-tier dongle DAC and the most expensive option in this group at around $350. Its design is deliberately simple: a single 3.5 mm output and a USB-A plug that connects straight into the host device. There is no onboard volume control, so the listening level is set on the computer or phone.

Inside, the Cobalt uses the ESS Saber 9038Q2M DAC chip. It is also the only model here with MQA support, which matters if that format is part of your library. For anyone who wants MQA, the Cobalt is effectively the only choice in this comparison.

Sound is where the Cobalt makes its case. It concentrates on the upper midrange and the top end, which produces a lot of detail and a very clear presentation of fine information in a recording. Build quality is substantial, although the unit used here already showed some paint chipping, so an older or used example may not look pristine. A short USB-A to USB-C cable is available for connecting it to newer laptops.

AudioQuest DragonFly Red

The DragonFly Red sits in the middle of the DragonFly range at around $200. It keeps the family’s compact plug-in format and offers a step up from the Black without reaching the Cobalt’s price. For listeners who want the detail-forward DragonFly character and cannot stretch to the flagship, this is the natural compromise.

It is also the model to consider if clarity is the priority but the budget is fixed. The Red is priced above the Fosi Audio DS1, so the value argument depends entirely on how much you want the DragonFly sound and format.

AudioQuest DragonFly Black

At around $100, the DragonFly Black is the entry point into the DragonFly line. It keeps the same plug-in, cable-free approach and makes the family’s character available for the least money. If you want to stay within the AudioQuest ecosystem and keep the spend low, this is where to start.

Fosi Audio DS1

The Fosi Audio DS1 is the value story of this comparison. At around $77 it undercuts everything else here, yet it offers more connectivity than the Cobalt: balanced and single-ended outputs plus an onboard volume control. It uses a USB-C input and comes with a cable, so it connects to a phone or a laptop directly, and an adapter is available for devices that only offer USB-A.

It also uses the same ESS Saber 9038Q2M DAC chip as the Cobalt, but it does not sound the same. The DS1 puts noticeably more weight at the bottom end and comes across as more dynamic and lively, closer in character to the loudness button on an old receiver than to a strictly neutral monitor. The top end still carries detail, though the Cobalt pulls out a little more of it.

The one clear omission is MQA, which the DS1 does not support. If that format is central to your setup, this is not the model for you. For everything else, the combination of price, outputs and character is difficult to argue with.

Hidizs S9 Pro

The Hidizs S9 Pro rounds out the group with balanced and 3.5 mm single-ended outputs and the same ESS Saber 9038Q2M chip found in the Cobalt and the DS1. Its sound lands remarkably close to the Cobalt, which makes it an interesting alternative for listeners who want that detailed, upper-register-forward presentation with a balanced connection available.

The trade-off is build. The S9 Pro does not feel as substantial as the Fosi Audio DS1 or the Cobalt, and the USB-C port on the unit used here already felt loose. That may come down to the cable rather than the port itself, but it is worth checking on arrival and swapping the cable if the fit feels vague.

Overall Buying Advice

The right pick comes down to budget and to the sound you are chasing. If detail and clarity are the priority, and especially if you listen to jazz, classical or other material where fine detail carries the performance, the DragonFly Cobalt is the strongest performer here. It is also the only model in this group with MQA support, and it feels the most substantial in the hand.

If you want a fuller, more energetic presentation at the lowest price, the Fosi Audio DS1 is the standout. Balanced output, an onboard volume control and a price around $77 make it a straightforward recommendation, and the fact that it shares the Cobalt’s DAC chip while sounding completely different shows how much tuning matters.

The DragonFly Red and the DragonFly Black remain sensible choices for anyone who wants to stay within the AudioQuest family, with the Red the closer match for detail-focused listening on a tighter budget. The Hidizs S9 Pro is the nearest thing to a Cobalt alternative in sound, with balanced output on hand, though its build is less reassuring.

Conclusion

Five dongle DACs, one shared chip across three of them, and five genuinely different propositions. The Cobalt earns its premium price with detail, MQA support and build quality. The Fosi Audio DS1 wins on value and character, and the Red, the Black and the S9 Pro each cover a specific middle ground. Any of the five will lift a laptop or a phone well above its built-in output, so the decision is really about which character and which features match the way you listen.