Outboard DACs

Like many converters designed for use with smartphones and tablets, the Onyx has a highly compact design that measures just 210mm long, so you can slip it into your pocket. It’s a little chunkier than some of its rivals, but that’s down to the use of both an ESS ES9281 Pro for the primary DAC chip along with THX’s own AAA – ‘achromatic audio amplifier’ – to provide what it describes as: “satisfyingly loud” sound.

The Onyx has a standard 3.5mm headphone output and a USB-C port for computers and mobile devices, with a USB-A adaptor bundled. It works with Macs and Android devices, with volume controlled by whatever is playing the music. It only works with Windows 10 on PCs, while iPhones or iPads will require a Lightning adaptor (£30).

The Onyx supports hi-res audio formats, including PCM up to 32-bit/384KHz and DSD128, and also acts as an MQA renderer, which makes it ideal for use with Tidal. The USB interface draws power from the mobile device it is connected to, so it doesn’t have a battery of its own that needs to be recharged.

Sound quality
Kicking things off with The Streets’ Dry Your Eyes – available in MQA format on Tidal – the Onyx delivers the gentle strumming of the guitar with a light, warm resonance that could fool you into thinking you’re listening to an acoustic set in a folk club. But it’s the aggressive, staccato percussion that tells you this is no Ed Sheeran tear-jerker. There’s a taut, gritty texture to the sound, as though Mike Skinner’s geezer persona is jabbing his finger into your chest, both angry and heart-broken at the same time. Then, at exactly the halfway mark, the percussion pauses, giving way to the bittersweet tone of the strings. The Onyx knows this is the moment to step back, allowing the sound to hang in the air, resonating for just a few seconds, as Skinner confesses: “Everything’s just gone, I’ve got nothing”. Meanwhile, it does a great job of contrasting the different extremes of anger and sorrow in the song.

Next up, Maria, one of my favourite later-Blondie hits that I still own on CD. The opening guitar riff has the irresistible catchiness of the band’s Seventies classics, with a light touch of reverb to wrap your head in the sound and draw you in. But it’s Clem Burke’s drums and percussion that really make this track, and the Onyx catches all the little details as the tambourine shimmers lightly in the background and the crystal clear bell-chimes add a celebratory tone that just yells party time. The THX amp-chip delivers too, with plenty of power to get the mood swinging.

Moving to something altogether more gentle, the Onyx deftly handles the more sombre tones of Jóhann Jóhannsson and his collaboration with Theatre Of Voices on Orphic Hymn (from the Orphée album). The multi-layered monastic chant rises slowly, creating a great sense of space. The tone is warm at first, but the crystal clarity of the falsetto adds a sense of urgency that befits the tale of Orpheus and his perilous journey through the underworld.

Conclusion
The profusion of connectors and interfaces now used by computers and mobile devices means that the Onyx may not be the perfect solution for everyone, but if it’s compatible with your devices then the compact design and impressive clarity of sound make this a great option for people who like to travel light. CJ    

DETAILS
Product: THX Onyx
Type: Portable DAC/headphone amplifier

FEATURES
● ESS ES9281Pro and THX AAA-78 processors
● 32-bit/384KHz PCM; DSD128; MQA
● 3.5mm out; USB-C