Periodic Audio Rhodium review: boost smartphone or laptop audio with ease

Wireless headphones are everywhere you turn right now. And it’s hardly surprising, is it? After all, does your smartphone have a headphone socket? Almost certainly not.

Trouble is, anyone who takes portable listening seriously knows ‘wired’ beats ‘wireless’ every day of the week where pound-for-pound sound quality is concerned. 

So what do you do if you want to use your favourite wired headphones with your socketless smartphone? Or you want to plug them into your laptop’s headphone socket without being offended by the god-awful sound quality that every laptop serves up? 

Periodic Audio reckons you should deploy its Rhodium USB DAC/headphone amp. Here's what we reckon...

Periodic Audio Rhodium: Price & Availability

The Periodic Audio Rhodium USB DAC is on sale now. It costs £49 in the UK, $49 in the United States and AU$79 or thereabouts in Australia.

So this tiny little product costs a (relatively) tiny amount of money. But if Periodic Audio is to be believed, the Rhodium will make a great big difference to your listening pleasure. It’s not how big your DAC is, after all - it’s what it can do for your sound. 

Periodic Audio Rhodium review: Features

The Rhodium is designed to sit between your smartphone and your wired headphones - and as a consequence it’s small, functional and only has the essential features.

There’s a Realtek ALC5685 system-on-chip, that's just 6 x 6mm, inside the little aluminium housing at the USB-C end of the Rhodium. It’s capable of outputting PCM digital audio files to a maximum resolution of 32bit/384kHz - and Periodic Audio is quoting some startling performance figures. 

Frequency response of an ultra-low 5Hz to an ear-splittingly high 160kHz, for example. Total harmonic distortion of a negligible 0.007% and signal-to-noise ratio of 108dB. Add in extremely low power consumption and the Rhodium seems ready to outperform even the most optimistic customer’s expectations when price and configuration are taken into account. 

The only flourish as far as ‘features’ are concerned is the USB-C / USB-A adapter that gives this DAC wider compatibility.

Periodic Audio Rhodium review: Performance

My MacBook Pro is a splendid laptop in many ways, but it’s a frankly abysmal source of music. Whatever the DAC chipset Apple specified behind the 3.5mm analogue output, it’s hamfisted in the extreme. So by plugging the Periodic Audio Rhodium into one of the laptop’s USB-C-shaped Thunderbolt 3 inputs at one end and attaching a pair of Audio Technica ATH-WP900 over-ear headphones at the other, it’s sure to sound better than plugging the 900s directly into the headphone socket. Isn’t it?

Well, yes it does - and by a margin. That’s not to say it’s perfect, mind you.

On the ‘plus’ side, the Periodic Audio DAC is a considerably more direct, detailed and positive listen. Compared to the unassisted sound of the laptop, it extracts a whole heap more information from a recording, particularly through the midrange - which means a singer sounds altogether more engaged, more characterful and more attitudinal this way. If you’re even remotely interested in the technique or emotional state of a vocalist, the Rhodium makes it far more apparent.

Low frequencies, too, gain a lot of focus, control and positivity. There’s greater punch to bass sounds delivered by this DAC, straighter and better-defined edges at the attack and decay of individual hits or notes, and far more information regarding texture and timbre. The laptop by itself tends to shove, but the Rodium hits. 

Soundstaging is improved too, insomuch as the stage is bigger, better laid-out and easier to understand. Rhythmic expression is more confident, thanks in large part to the superior control of the low-end frequencies. And overall tonality is (almost entirely) better described and more wide-ranging.

It’s at the top of the frequency range that problems, such as they are, exist. The Periodic Audio attacks treble sounds almost gleefully, sinking its teeth in and giving the top end plenty of shine and crunch. And by ‘plenty’, I guess what I mean is ‘too much’. There’s an almost feral quality to the way the Rhodium describes treble information, a relentlessness that makes it quite wearisome to listen to at realistic volumes and downright tiring the more you wind the volume up. ‘Perky’ is all well and good, ‘insistent’ not so much.

Periodic Audio Rhodium review: Design & Usability

As with ‘features’, the ‘design’ aspect of the Rhodium can be dealt with in next-to-no time. As befits a product intended to sit between your smartphone’s USB-C socket at one end and the 3.5mm jack of your wired headphones at the other, this is a functional design.

The Rhodium weighs 6g. At one end there’s an aluminium USB-C plug and there’s an aluminium 3.5mm analogue connection at the other. In between, there’s 63mm of nicely braided cable. 

That’s it for ‘design’ - and as far as ‘usability’ goes, well… plug the USB-C end into your smartphone or laptop, and plug your headphones into the 3.5mm analogue connection. It seems unlikely you’ll become confused as to what’s what here.  

Periodic Audio Rhodium review: Verdict

The difference such a small and affordable device can make to the audio performance of your laptop or smartphone is undeniable - but the way the Rhodium handles high-frequency sounds means it’s not quite a no-brainer.

Also consider

Even though it’s just 10g and 43 x 15 x 8mm, the Fiio KA1 USB DAC looks quite a biffer next to the Periodic Audio Rhodium. It’s a slightly more rounded and better-balanced listen, though, and has MQA and DSD support too. Plus it’s a touch more affordable, which doesn’t do any harm either.