Cyrus Audio ONE Cast ‘Smart Amplifier’ Review

Posted on 4th February, 2020

Cyrus Audio ONE Cast ‘Smart Amplifier’ Review

The Cyrus ONE Cast ‘smart amplifier’ is an intriguing new integrated, says David Price…

Cyrus Audio

ONE Cast 'Smart Amplifier'

SGD $2,599 MSRP

The story starts back in the early nineteen-eighties when Mission Electronics began work on an innovative amplifier called the 778. A compact half-width integrated designed by Henry Azima, when launched in 1983 it boasted independent source and record selectors, a good MM/MC phono stage and 2x50W of MOSFET power for £240 in the UK. It laid down the blueprint for every Cyrus amplifier on sale since – including the new $2,599 Cyrus ONE Cast you see before you. A fine sounding yet flexible package, it was dramatically different to all the gadget-festooned amplifiers of that time – and sounded nothing like them either. 

The little 778 spawned Mission's new Cyrus range in 1984 – the Cyrus One was effectively a cost-cut 778 with less power, while the Two was an improved 778 with similar power. Selling for around £125 and £250 respectively, these two pint-sized, half-width amplifiers caught the zeitgeist and set the nineteen-eighties hi-fi world on fire. The company followed this winning formula ever since. When Mission's electronics division was sold off in the early nineties, it went solo as Cyrus launched the Cyrus 3 integrated in 1993. This had similar dimensions to its predecessors, but a more sophisticated case and a sleek, microprocessor-controlled user-interface. For nearly twenty-five years Cyrus sold only variations on this theme until it launched the ONE in 2016.

You might say this was the reinvention of the original Cyrus One – here was the company returning to its roots with a compact, affordable do-it-all design with better performance than you'd expect at the price. The new ONE had a plethora of inputs including a phono stage and Bluetooth, while its new satin black case had an edgier, more striking look than the company's nineties-era separates. The decision to use a Class D power amplifier section was a surprise, and this carries over to the new ONE Cast version you see here.

This new model uses the latest evolution of this technology, being the company's fourth-generation version that was first seen in the Cyrus ONE HD a couple of years back. It's based on the third-generation design but with a retune of some components, according to Managing Director Simon Freethy. “This is designed to be more forgiving of cheaper loudspeakers without losing the fast attack and wide soundstage that the amp produces. Its output stage efficiency is around 95%”, he told me. 

The use of Class D is pivotal to the ONE. Simply put, it would have been impossible to build it in Class AB form. The design brief calls for 100W per side into 6 ohms, which requires ultra-efficient Class D with its minimal heat soak. Indeed, despite this amp's diminutive dimensions, there are no cooling fans or heatsinks inside, which is remarkable considering its claimed power. 


Yet for the new ONE Cast, the real headline news is its voice-assist technology – thanks to its implementation of a relatively new Frontier Silicon streaming platform. Although this has appeared in other smart devices, this is the first real hi-fi application, and that required Cyrus engineers to work with the hardware supplier to increase its native resolution while retaining that advanced voice functionality. “We are the first company to implement this tech”, says Simon.

The ONE Series was designed to be an affordable, versatile, quality hi-fi package in one single box. “This means it is just as the original Cyrus products were all those years ago – but now with steaming as its core source.” So it's a sort of thinking man's Sonos, then? “Absolutely – this is always where we have seen this product positioned. It has all the convenience that Sonos customers have bought into, but with much higher musical performance. It's somewhere for existing Sonos customers to migrate to, as they get frustrated with the actual musical enjoyment – or lack thereof – they are getting.” The fact that the ONE Cast has the ability to work as an internet-connected smart device but sound better than others, is central to its appeal.

Trick voice assistance and network streaming aside, it's a mixture of the original ONE and the ONE HD. It has the original's analogue input and moving magnet phono stage, but adds DAC functionality thanks to the ONE HD's ESS 9018-based digital convertor board, capable of working at up to 32-bit/192kHz and DSD 128 via its hi-res USB input. It sports both TOSLINK and coaxial digital inputs, too. The new ONE Cast does not share the ONE HD's aptX HD Bluetooth streaming, however, because Cyrus thinks that those who want to stream will do it by Wi-Fi. So it's back to good old aptX Bluetooth, which isn't bad for background listening. There's also a Class AB headphone amplifier, Apple AirPlay2 functionality and an HDMI ARC input which gives a direct connection to a thus-equipped TV, removing the need for a soundbar.

The ONE Cast can be voice-activated by Google Assistant, Amazon Alexa and Apple Siri, and connects wirelessly to mobile devices. Music streaming is possible direct from any of the major music services without the need for a dedicated Cyrus app. Instead, you need to load the Google Home app to your smartphone or tablet (available in Android or iOS), which then effectively sets up the ONE Cast's internet connectivity for you. Then it's a case of opening your streaming app (I use Qobuz), selecting the ONE Cast as the device you want to send music to, and then playing whatever you like. Simon says it was done this way deliberately, so as not to “blunt the satisfying user experience of existing music streaming apps”.

ONE Cast can also be used as part of a multi-room audio set-up, but Cyrus has deliberately eschewed an Ethernet port and gone for Wi-Fi operation only, with twin captive antennae at the back. “This is because we wanted a product that's as simple to place and use as a typical smart speaker. Even fairly average Wi-Fi can cope with the bandwidth required to run high-res streams and this way you're not restricted to placing it near an RJ45 terminal.”

Using it is easy. If you have a smart speaker such as an Apple Homepod, Amazon Echo Dot or Google Home on the same Wi-Fi network as the ONE Cast, you can use voice commands to send music to it. Even if the amplifier is in standby, it will wake up when it hears a voice command like “Alexa, play some cool jazz on ONE Cast.” As it's controlled by a networked smart speaker, it works with all their standard control phrases, so you can ask for exact tracks or specify an internet radio station, for example. Like a smart speaker, the amp can be assigned to a room or even a group of rooms. Firmware updates are done automatically.

With its powder-coated black metal body and acrylic fascia, the ONE Cast doesn't have the superlative build quality of its bigger, more expensive brothers – although its 85x220x390mm (HxWxD), 5.6kg case is still a fine piece of industrial design and looks crisp and modern. You're treated to a light show on switch-on, which is the amplifier's only concession to gimmickry. A small, basic infra-red remote control is included, but the unit is nice to use directly, even if the two control knobs feel a little lightweight. 


A number of gloomsters in the hi-fi world have long since decreed that Class D is in some way “not musical” and “no fun.” Anything that uses it then, they argue, should not be accorded any seriousness as a listening tool. Integrated amplifiers like the Cyrus ONE Cast show just how wrong they are because this turns in a high-quality sound that leaves one wondering how it's all possible at the price. Indeed, it's a most impressive, listenable little amplifier that impresses across all its myriad inputs.

I'm a huge fan of the original Mission Cyrus range, but even an old-school purist like me can't help but concede that the new ONE Cast does an awful lot rather well, sonically. It has a surprisingly rich, creamy sound that lets the listener relax into the music and enjoy the occasion. There seems to be far more power than is normal for an amplifier of this physical size, and it translates to a full-bodied, confident sound that tackles the recording head-on, without fear or favour. This little integrated isn't scared of powerful basslines, dramatic dynamic crescendos or soaring, expressive vocals. The result is both suave and sophisticated, punchy and powerful.

Take Life's Mood by Isaac Hayes for example. This early nineties soul classic has crashing electric piano cadences that push the song along. Via the RCA line input, the Cyrus ONE Cast communicated this with great aplomb, setting up a wide recorded acoustic. From this, the deliciously creamy vocal line floated out with real authority, with scratchy rhythm guitar and percussion filling in behind. The power of the sound seemed to be inverse proportion to the size of the amplifier – yet it wasn't just full and flat. It had plenty of punch in reserve to capture the dramatic impact of the keyboard playing and the spacious backing string accompaniment.

Indeed, there's plenty of room to roam inside the Cyrus ONE Cast's soundstage; it's not just its smoothness of tone that gives this full-bodied feel, it's the expansiveness of the sound. There's a widescreen feel to the proceedings that's always there, whether it's classic eighties stadium rock like Simple Minds' Speed Your Love to Me, or Kate Bush's Snowflake piano ballad of a few years back, that you're playing. Indeed via the digital input feeding its internal DAC, the amplifier appears even larger and more spacious than via the analogue in. The Cyrus actually has a rather epic feel – it suits large scale productions, where it shows off their breadth with skill. There's a good deal of space from left to right, with stereo images confidently located and unwavering within the mix. It's not quite so impressive in terms of depth perspective – lacking as it does the three dimensionality of pricier integrateds like Exposure's 3010S2-D – but you have to remind yourself of this product's modest cost.

So with power and punch, sophistication and scale, there's much to like about the new Cyrus – but the story doesn't stop there. Feed it with some frenzied nineties drum and bass like Manix's Oblivion – via its USB input – and it really comes alive. The ONE Cast has a fast, nimble sort of sound that doesn't slur the pile-driving piano riff or soften the attack of the frenzied electronic percussion. Indeed, it pushes the groove along with real zeal, making for an engaging presentation. It's not quite the most fluid sounding integrated at this price – Roksan's K3 does better for example – but then again we're kind of comparing apples with eggs. Give this amplifier a crisp, pounding beat, and it jumps in and gets the job done, wielding its not inconsiderable muscle with heady abandon, and clearly signposting the size of the recorded acoustic.

Sonically, the Cyrus proves very good at a lot of things then but isn't outstanding in any one way. Whether it's streaming The Who's new WHO album from Qobuz or playing a scratchy copy of Who's Next via its phono input, it makes a nice noise that's hard not to like. It has great amounts of grunt for something so small and doesn't lose the plot when you run it loud and hard for prolonged periods of time with tricky speakers such as my reference Yamaha NS-1000Ms. Just when you feel you should be criticising it for something – such as its slight opacity in the midband that stops you hearing right to the back of the mix, for example – you have to pinch yourself and remember that it's only £1,299. The clever thing is that the ONE Cast hides its tracks so well that you are never conscious you're listening to an affordable amplifier – something that's closer in price to a Cambridge Audio than a Krell. 


There are some fans of this brand who will die listening to their original eighties-vintage Henry Azima-designed Mission Cyrus Ones and Twos, swearing blind that these have never been bettered, til they slip off their mortal coils. The Cyrus ONE Cast was never built for diehards like these. 

Rather, it's made for people who want an ultra-flexible, small-footprint amplifier that's perfectly at home in the internet of things. Voice-assist won't be for everyone, but if you are that way inclined then it's actually very handy – and a worthwhile feature to have. And the more you use Google Home, streaming apps and smart devices – the harder it is to go back.

As a self-contained music maker then, the Cyrus ONE Cast is superb. It brings the future one-step closer, in a neat, beautifully designed package. Yet it also works surprisingly well as an old school integrated amplifier. A jack-of-all-trades and master of some, it appeals to Sonos upgraders and audiophiles alike – so is surely the shape of things to come?

For more information, visit Cyrus Audio.

    David Price's avatar

    David Price

    David started his career in 1993 writing for Hi-Fi World and went on to edit the magazine for nearly a decade. He was then made Editor of Hi-Fi Choice and continued to freelance for it and Hi-Fi News until becoming StereoNET’s Editor-in-Chief.

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    Posted in:Hi-Fi
    Tags: cyrus audio  eng siang