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It seems we’re in the age of the mkII amplifier, as manufacturers by-pass the need to replace established models with new ones treated to a fresh styling job – expensive business, that – and instead concentrate on some serious tinkering under the lid to improve performance. In recent times we’ve seen Rotel’s premium brand, Michi, doing just that with its X3 and X5 models and now it’s London-based Cambridge Audio’s turn, with a mkII version of its CXA81 amp which looks exactly like the model it replaces, right down to its distinctive Lunar Grey finish, which is shared with the company’s other hi-fi components.
Given that the original CXA81 was an impressive performer, and a worthy replacement for the CXA80 a few years back, it’s tempting to ask ‘why bother?’. But it’s reassuring that this new mkII version enters the fray at the same price at which the original was launched back in 2022 (although that model has now been repositioned at £799 to make way for the newcomer), and that the Cambridge Audio engineers have resisted the temptation to ladle on extra features, potentially at the expense of sound quality.
So, the CXA81 mkII remains a minimal-looking device, with an aesthetic reminiscent of the company’s flagship Edge line-up - it even shares an instruction manual with the old CXA61 and CXA81 models. The smooth-acting volume control at the right-hand end of the front panel dominates the look, with a black panel mounted amidships containing little buttons for input selection - each having a legend beside it that illuminates when selected - and speaker A/B/A+B switching. There’s also a slick Cambridge CX system remote control. But apart from a power button and a 3.5mm headphone socket completing the fascia, that’s your lot. This is an amplifier free from visual flash, leaving its sound to do all the talking.
Designed and engineered at the company’s London HQ (just about in the shadow of the Shard when the sun’s shining in the right direction) and made by Cambridge’s own Chinese production facility, the CXA81 mkII is a long way from the simple amplifiers with which the brand started afresh under new ownership in 1994. Since then, under the umbrella of Audio Partnership, it has refined both its sound and its industrial design, and expanded its offering to everything from in-ear headphones to very high-end preamp/power amp systems (without the high-end pricing, however) and its sleek EVO all-in-one network player/amps.
The CXA81 mkII sits at the head of its mainstream hi-fi range, and has a competitive feature-set: four line-level analogue inputs, with one having a balanced-in option, and four digital, including a USB-B for connection to a computer source, and with the ability to handle both 24-bit/384kHz and DSD256. There’s also Bluetooth with aptX HD capability, handy for portable devices and the company’s own wireless Alva record players.
As well as the twin sets of speaker outputs, the amp has pre-outs to feed an external power amp, and a mono subwoofer feed filtered to pass only frequencies below 2.3kHz - which makes life easier for the crossovers in active subs and keeps the signal fed to a sub as clean as possible. Meanwhile, there’s also an array of control connections including the usual 12V trigger ports and the company’s own control bus, for which a cable is provided in the box.
The power behind that digital section is the first of the innovations here: the CXA81 mkII uses the ESS ‘Sabre’ ES9018K2M digital-to-analogue converter, replacing the ES9016K2M used in the original version of this amp. Yes, these Sabre DACs have become near-ubiquitous in recent times, not least due to the supply problems experienced by rival AKM after a disastrous factory fire in Japan back in 2020 - but the chipset in use here, while more ‘tried and tested’ rather than exactly ‘new’, is a decidedly superior offering from the ESS catalogue.
And the Cambridge engineers have done more than just bang in a new DAC chip: close attention has been paid to the analogue section of the amp. Lengthy component-swapping listening tests led to the replacement of 10 op-amps, building on the improved DAC with what the company says is ‘even greater clarity and musicality’.
Sound quality
While many other brands have switched to Class D or hybrid power amplification, Cambridge sticks to what it knows best - good old Class AB - simply because it believes it sounds best. Traditional, too, is the power behind the amplifier: a conventional, well-sized toroidal transformer provides the juice for the CXA81 mkII to deliver 80W per channel into an 8ohm load, rising to 120W a side into 4ohms. So not only does this amp feel expensive when you operate its controls, it sounds that way, too.
And playing no small part in this is the combination of a direct, revealing sound allied to serious bass weight and richness - this is an amp with not a hint of fragility or brashness about the way it plays music. What’s more, there’s no shortage of power: you can set the amp to reduce the volume if it’s overdriven to the point where clipping may occur, but frankly you’d have to be going seriously bonkers with the volume control if you were ever to encounter this in normal domestic circumstances.
There’s more than enough oomph to drive just about any speaker to levels well on the exciting side of sensible, and the CXA81 mkII does so with real grace and control. It really brings out the details in even complex mixes, while delivering instruments and voices in an entirely persuasive manner. Soundstaging and image focus are superb with well-recorded tracks, and the amp can kick hard when the bass and drums require it, or deliver large orchestral works with realistic scale and presence.
What’s more, you don’t have to push the levels for the amp to sound exciting: some designs can sound a bit dull when playing quietly, only blooming when they start working hard, but there’s none of that here. Instead, you get an open and clean presentation from the start, and simply the same, but louder, when you crank up that silky-smooth volume control a bit more. Which is just as it should be.
Living with
Yes, this is a relatively simple amplifier - Cambridge Audio will point you to other models in its catalogue should you want extended functionality, such as the CXN100 network player (which has balanced outputs to match the CXA81 mkII’s inputs) and its Alva record-playing range (which includes phono stages as well as those wireless turntables). But simplicity’s no bad thing when it comes to maximising sound quality.
Partner it with a pair of high-quality speakers - I use my ‘go to’ choice of the moment, the compact but weighty and revealing PMC Prodigy 5 floorstanders - and the sound leaves nothing to be desired. In fact, only when moving up to another of my references, Naim’s Supernait 3 integrated, do I detect a little more detail and rhythmic drive - but then the Naim is an even simpler amp, albeit of similar power to the Cambridge Audio. And there’s also the small matter of a price tag more than four times that of the CXA81 mkII.
Conclusion
This may at first appear little more than a marginal upgrade on the model it replaces, but the combination of an improved digital section and revisions and re-tuning in the analogue department has given it a compelling sound, as adept with the demands of small-ensemble chamber music or a lovingly-recorded jazz trio as it with a bombastic live rock track or a full symphony orchestra.
Add the subtlety of its design, the precision with which its controls operate, and the quality of both the build and the finish, and this is serious value. It’s more than able to challenge some much pricier integrated amps when it comes to both performance and user-appeal.
Listening notes
Rachel Podger/Brecon Baroque Lawes – Sonata No. 8
Beautifully recorded, violinist Podger’s latest release, The Muses Restor’d, positively sparkles with detail (especially in its DSD256 release), making the most of the capabilities of the CXA81 mkII’s digital section. Superb soundstaging combines with ‘reach out and touch them’ instrumental timbres.
John Williams The Knight Bus
From the soundtrack to Harry Potter and the Prisoner of Azkaban, this track opens with reflective woodwind before breaking into the jazzy mayhem of the famous triple-decker bus careering through the dark street, the bass, dynamics and complexity showing off all the Cambridge amp can do.
King Crimson Matte Kudasai
Taken from King Crimson’s 1981 album Discipline, this lush track, laden with romantic guitar effects from Adrian Belew’s guitar and Robert Fripp’s guitar synth, underpinned by languid bass and drums, shows off the Cambridge amp’s warmth and transparency. If you thought Crimson was all about thundering prog, think again.
The Cambridge CXA81 mkII presents a simple, elegant face to the world, and the engineering within follows the same path. The result is an exceptional amplifier for top-notch systems, and excellent value for money.
