Taking History for a Spin: A Full Review of the THX Onyx Portable DAC Headphone Amplifier

Manufacturer & Model
THX Onyx Portable DAC Headphone Amplifier
MSRP
$199.99
Link
https://www.thx.com
Highlights
Powerful THX AAA amplifier technology, MQA certified, ESS ES9281PRO DAC, multi-platform compatibility for plug-and-play use, excellent sound quality.
Summary
THX Onyx is THX's first-ever consumer product, offering incredibly powerful DAC/Amp performance in a small, flexible form factor. It's plug-and-play with iOS, Mac, Android, and Windows 10 devices, and has onboard MQA rendering capabilities for top-flight Hi-Res audio playback. Onyx delivers as promised, powerfully driving headphones with crystal-clear audio.
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Long before THX began certifying home theater and electronics equipment, it was busy transforming the commercial cinema experience. As the story goes, George Lucas and company left a botched screening of The Empire Strikes Back in 1980, frustrated by the theater's poor audio capabilities. Rather than accept the status quo, Lucas collaborated with audio scientist Tomlinson Holman to create a cinema certification program, and THX Certification was born. It’s since become a symbol of quality that's permeated the ranks of consumer products, standing as a seal of guaranteed performance.

Today's review is unique because the subject – THX Onyx – is the certification firm's first-ever consumer hardware product. Onyx isn't too dissimilar from the DAC/Amp featured in my last review (HELM Audio's BOLT DAC/AMP), but its output capabilities are more powerful thanks to the company's use of its proprietary Achromatic Audio Amplifier technology (THX AAA).

Priced at $199, Onyx officially goes on sale today (April 7, 2021) through THX.com and razer.com in North America, Europe, and APAC, and JD.com and tmall.com in China.


Overview
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THX Onyx is essentially a processor and amplifier squeezed into a tiny form factor. Measuring 8.25" from end-to-end and no more than 0.50" wide, its flexible cord and magnetic clasp allow the device to fold into a 4.5" long package that's easily stowed away. The totality of its diminutive weight (0.63 oz) allows Onyx to remain incredibly manageable during use and storage on the go.

While Onyx doesn't carry official THX Certification, its brand name serves notice that it meets any and all certification requirements set forth for mobile DAC products. It is, however, MQA Certified, which means it unfolds and renders MQA tracks sourced from streaming services such as TIDAL. And while MQA heralds itself as the ultimate digital audio experience, Onyx is more than capable of handling other types of High-Resolution audio sourced from various devices and streaming services.

THX highlights Onyx's ability to accept MQA through a host of apps, including TIDAL HiFi (PC, Android, Mac, and iOS platforms), USB Audio Player Pro (Android), Amarra (PC, Mac), Audiravana (PC, Mac), and Roon (PC, Mac).

Onyx's output capabilities are robust, offering 180mW per channel (0.2 ohms, <0.1% THD, -112dB THD+N) and the ability to drive all types of headphones, even power-hungry models. This is made possible by THX's proprietary THX AAA-78 amp module, which is making its debut in a mobile device.

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Achromatic Audio Amplifier technology employs a patented configuration of feedback and feed-forward error correction that attacks various types of distortion commonly found in power amplifiers. It utilizes resistors and capacitors, not bulky inductors, allowing THX to shrink the entire system into an incredibly small package. The resulting output is clean and fatigue-free due to a notable reduction of harmonic, intermodulation, and crossover distortion. It’s also billed as being less power hungry than competing technologies, helping to extend a source device's battery life.

ESS Sabre's ES9281PRO DAC performs digital-to-analog conversion duties in Onyx. It natively supports PCM up to 32-bit/384 kHz and DSD via DoP 64/DoP 128 input, and accepts MQA at 88.2/96 kHz/24-bit before unfolding and upsampling to 705.6/768 kHz for digital-to-analog conversion.


Unboxing and Set-Up
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Adhering to the demands of its $199 price tag and brand image, Onyx ships in an attractive box with a magnetic lid flap. The exterior of the box features snazzy photos and details about Onyx's technologies and capabilities, and its weighted lid flips open and closed with smooth movement. Inside, a visual quick start guide is printed on the lid's backside, while Onyx and a USB adapter are safely stored in a contoured foam cutout.

Onyx is a slick-looking device, cloaked in jet black and flaunting a shiny THX logo embossed on an all-metal CNC-machined body. It really pops, visually, and feels good to the touch. The USB-C input connects to the headphone output with a thick rubberized cable. This cable is flexible enough for the USB-C's magnetized backside to attach to the bottom of the headphone output, forming a cable management loop. The loop is an interesting idea, but proves to be relatively inconsequential. Yes, it works, but you'll find a better result using a velcro cable organizer.

The headphone output houses the ESS Sabre DAC and THX-AAA amp, a 3.5mm TRRS audio jack (supports microphone headsets on Mac, PC, and Android), and three multi-color LED lights.

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Onyx is billed as plug-and-play with Mac, iOS, Android, and Windows 10 PCs when plugged directly into a USB-C or USB port; no drivers are required. Much like Helm Audio's BOLT, Onyx can't connect directly with an iOS device, requiring the use of Apple's Lightning to USB Camera Adapter. Apple's adapter costs roughly $30 and adds approximately 5" to the setup's overall length – not ideal, but manageable.

Three LEDs visible on the headphone output are animated, indicating when the DAC/Amp is active upon startup and relaying sample rates during use. Onyx displays blue for standard quality (44.1 or 48 kHz PCM), yellow for Hi-Res (>48 kHz PCM), red for Direct Stream Digital, and Magenta for MQA rendering.


Listening Impressions
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I'm an Apple guy, so I paired Onyx with an iMac (macOS Big Sur) and an iPhone 11 Pro (iOS 14.4) for playback of TIDAL’s Hi-Res tunes using Oppo's PM3 and Acoustic Research's AR-H1 planar magnetic headphones. Onyx had zero issue driving either model to extreme heights.

Connecting Onyx to my iPhone (via the Apple USB adapter) was straightforward; however, connecting it to a Mac required an unforeseen step. Using TIDAL's desktop app, the Mac didn't immediately optimize output for MQA, defaulting output to standard quality. To achieve MQA playback, I stumbled upon a “More Settings” option in TIDAL's Sound Output menu. There, I authorized TIDAL to "Use Exclusive Mode," which the app says affects HiFi and MQA playback. No biggie, but not exactly evident.

As compared to Apple's standard lightning to 3.5mm adapter, Onyx injected serious life into listening sessions. Tracks exploded with more authority and pizzazz, shedding the flatter and more smeared presentation offered by Apple’s device. Output was also notably robust and powerful, as Onyx's amp muscle is far more potent. The resulting sound was full of life and breadth, with a balanced attack from top to bottom.

Onyx readily identified playback resolutions, providing me with a magenta 'thumbs-up' when MQA tracks were in play. A song like Taylor Swift's "You Need to Calm Down" (MQA) was an ocean of revealing detail, bubbling with vibrancy. And a bass-heavy track like Deadmau5's "Three Pound Chicken Wing" (HiFi) throbbed with chiseled bass, etched with rich intricacies of its own. The Aphex Twin’s textured “aisatsana [102]” (HiFi) was also notable, possessing wonderful hints of realism as the physical movement of Richard D. James’s piano keys were magnified, gracing the track with a tangible analog nature.

At THX's suggestion, I launched Disney+ and watched the snowy forest lightsaber battle in The Force Awakens (time: 1:50.30 – 1:57.43). The entire presentation was seamless and crystal clear. Directionality was in full play, details – such as tree limbs snapping – sparkled, and low-frequency effects weren't shy about smoothly integrating into the audio presentation. Dialog, as heard in scenes from The Dark Knight (Netflix) and The Town (HBO MAX), was also pleasing to the ears, clearly delivering voices along with subtle lip smacks and whispery breaths.


Conclusion
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Color me impressed. THX's first step into the world of consumer audio gear is a big one, delivering the kind of quality you'd expect from a name associated with high-performance. Onyx is manageable in size and loaded with serious high-power output capabilities that deliver reference-quality audio. Even more, it operates without calling attention to itself, confidently crafting sound defined by a potent, yet natural, neutrality. Besides quibbling about the need for an Apple USB adapter during iPhone use, Onyx is a home run.

This kind of performance comes at a price that’s not exactly budget-oriented, but considering its ability to deliver refined audio and MQA rendering, it's worth the investment. Excellent Gear.

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THX Onyx Portable DAC Headphone Amplifier Specifications
  • Input Type: USB/USB-C
  • Output Type: 3.5mm analog jack, TRRS compatible
  • Headphone Impedance Range: 22-1000 ohms
  • Sound Quality (THD+N, 1kHz): -110dB
  • Dynamic Range: 118dB
  • Output Impedance: 0.2 ohms
  • Output Power (Per Ch, 22 ohms, <1% THD): 180mW
  • MQA Playback: Yes
  • Headset Mic Support: Yes (Mac, PC, Android); No mic on iPhone/iPad
  • Microphone Noise: 98 dB
  • USB & DAC Configuration: ESS ES9281PRO
  • Amp Configuration: THX AAA-78
  • Compatible Platforms: Android, iOS, Windows 10, Mac (Lighting to USB-C Camera Adapter, slim, not included)
  • Accessories: USB-A Male to USB-C Female Adapter
  • THX Certification: Not THX Certified, but meets all rigorous THX Certification standards for mobile DAC amps

 
Last edited:

Grayson Dere

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Thanks for the review! At $200 it's not super expensive but seems to really hit all the marks for great sound performance. If I ever need to add a portable DAC/Amp for my headphones I'll put these at the top of my list : )
 

Todd Anderson

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I’m curious how a THX product doesn’t meet THX Certification
It does, they just chose not to assign it. Would be redundant considering the brand ;-)
 

dhai

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Oh, great - my first post and missing a word:
would have been lovely
sorry
 

Todd Anderson

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Welcome to the forum @dhai! Glad you’re here!

Answer to your comparison question is easy...Onyx has more power output. So, it will handle more demanding headphones and can push louder volume levels. That said, my ears couldn’t handle max output from Onyx with the headphones I demoed with. I had to back it off...

BOLT, in my opinion, drove both head phones perfectly fine and to levels I wouldn’t push beyond with headphones.

Sound quality-wise... good luck hearing a difference. They both drive a crystal clear show.

Easy to recommend either one.
 

dhai

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Thank you, Todd,
this helps!

Sold the Dragonfly years ago, without replacement.
On the fly listening via Koss Porta Pro on the Mac is ok, these
slightly dull but nice-sounding headphones hardly resolve the difference.
Maybe the new generation is worth a try :)

Anyway, I hardly use the big Headphone gear,
flooding the room with music via loudspeakers gives me more of that
inspiring live-feeling.

Frankly, I shy forums, but here the vibe seems "positive" and therefore
I dared to ask my first question!
 

Todd Anderson

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:T The vibe here is all positive. We're a community that's here to drive each other forward. No such thing as dumb questions - everyone has something to share.:T

Based on what you're using - either one is worth a try... especially if you're streaming to a smartphone or computer using TIDAL, because both the Onyx and BOLT render MQA. While you may not be able to hear a definitive difference between MQA and CD quality, you are guaranteed precise digital to analog conversion. That's something that you'll likely to audibly distinguish.

The nice thing about both units is affordability, with the HELM BOLT being the cheapest. It's a win-win. Plus, if it's something that you're not loving, you could probably sell it on eBay for little loss :-)
 

typ44q

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Thanks for the review, I have read good things about the THX AAA amps. Nice to see one in such a portable form factor.
Would love to see it tested with some harder to drive higher impedance headphones.
 

symphara

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Does this work when connected directly to an iPad on USB-C? The newer iPads don't have the Lighting port anymore and no headphone jack, so I'm interested in one of these.
 

Todd Anderson

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This will plug directly into any USB-C port.
 
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