The last five years have seen the removal of the trusty 3.5mm jack from most phones, and while it started out with flagships, you’ll find many mid-range phones that don’t have the ubiquitous jack. At the same time, the audio industry has pivoted to the true wireless category, delivering wireless options that offer more freedom.
These days, you will find earbuds that sound good and provide decent battery life for as low as $30, and the best wireless earbuds sound nearly as good as their wired counterparts from half a decade ago — while offering a few additional features. While the wireless audio segment has matured, we’re now seeing a resurgence in wired audio, largely driven by the rise of lossless music streaming services.
With Hi-Fi gear largely limited to the wired segment, one option would be to pick up a USB-C to 3.5mm dongle to connect wired earbuds to your phone. But a better choice would be to go with a portable DAC. We’ve seen a few USB-C DAC/amps break ground in the last two years, and Helm Audio’s Bolt DAC is one of the most exciting options in this category.
At a high level, the Bolt is a $99 DAC/amp that connects over USB-C to your phone. You’ll find a USB-C connector at one end, and at the other end, you get a 3.5mm jack for plugging in your wired audio gear. Its diminutive profile means it isn’t that much larger than a dongle, but you’re getting a lot of features in that miniature chassis: it has 32 bit/384kHz PCM and DSD128 decoding, and it works as an MQA renderer, giving you the option to stream Tidal Masters straight from your phone. Oh, and it also has THX certification.
All of the hardware for the DAC is housed within a rectangular shell that features Helm Audio branding on one side and the MQA label along with a tiny LED indicator on the other. The LED gives you a visual indicator of source quality; blue is for audio under 48KHz, red is for source audio over 48KHz, and magenta is for MQA audio. Both the USB connector and the 3.5mm jack feature gold plating, and the 5cm cable connecting the two ends is of a high quality and built to last.
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The DAC weighs just 7.1g, making it one of the lightest and most portable options you’ll find today. Because of its size and the fact that it’s easy to lose, the packaging includes a leather pouch. You also get a USB-C to USB-A plug that allows you to use the Bolt with other devices.
The Bolt is designed in such a way as to isolate the ESS Sabre 9281A Pro DAC and the USB hardware, so there isn’t any interference, and you won’t notice any hiss when using the DAC with sensitive IEMs like the Fiio FA7S. It also delivers a power output of 1.1V over 150 Ohms, so you can use most IEMs and headphones with this DAC.
Although designed to work with your phone, the Bolt DAC pairs just fine with any source device, including Windows and macOS machines. It is a plug and play option, so you don’t have to worry about installing drivers. I used it for the last six months with over a dozen Android phones, and it had no problems whatsoever. I use Tidal for streaming and USB Player Pro for playing my local audio collection, and in both situations, the DAC was able to pass Android’s built-in USB decoding for its own hardware.
The Bolt delivers a neutral sound that’s full of presence and character. It is lacking in low-bass, but makes up for it with a lively mid-bass that shines through. Mids are similarly lively and detailed, and the DAC handles high frequencies with the same amount of gusto, managing to deliver clear notes without any harshness. It manages to faithfully recreate source recordings without missing out on any key characteristics, and that makes the Bolt a true powerhouse in this category.
Because of the fact that it runs off a USB-C cable, it isn’t easy to use the Bolt with an iPhone — you’ll need a Lightning to USB-C dongle and then pair the DAC. Most dongles cost $20 to $30 on their own, so I can see why there isn’t one bundled in the box — it would have pushed the retail cost to over $100.
There’s a growing list of portable DACs these days, and if you’re in the market for a high-quality option that is straightforward to use and delivers excellent sound, the Bolt DAC is a stellar choice. The fact that it works as an MQA renderer gives it a distinct edge in this category, and its diminutive profile means you can use it anywhere.
The Bolt DAC delivers powerful sound in a tiny package, making it the ideal option if you’re looking for a portable DAC to use with your phone. It has a durable design, renders MQA files without any issues, and the neutral sound characteristic allows your music to shine.