“Architecture aims at eternity,” said Sir Christopher Wren, architect of surely the world’s most famous rebuild after the Great Fire of London ripped through St Paul’s Cathedral in 1666.
Comparing such magnificent constructions with consumer hi-fi may be a crude parallel, but in rebuilding its 80W-per-channel CX series amplifier, Cambridge Audio has also designed something with the aim of offering that eternal quality.
The CXA81’s four-star predecessor wasn’t exactly in need of a ground-up reconstruction, but it didn’t stand so tall above hugely talented competitors in terms of features, design or sonic performance as this.
At a glance, neither this nor its 60W-per-channel CXA61 stablemate appear to have undergone radical changes since the series was first introduced in 2014; the Lunar Grey chassis and removal of balance and tone controls from the front panel are the only tweaks that are immediately obvious.
But though this new integrated amplifier’s basic analogue circuit remains unchanged, Cambridge Audio’s engineers have upgraded most of the op-amps in the signal path, as well as the capacitors in both the pre and power sections of the amp. The effect on performance is marked.
The CXA81 also houses a superior ESS Sabre ES9016K2M DAC and improved USB input that supports audio of up to 32-bit/384kHz and DSD256 quality, allowing you to make full use of its delightful presentation with high-resolution files, while an aptX HD Bluetooth receiver is also built in for direct streaming from any compatible device at up to 24-bit/84kHz. Previously, a separate dongle at extra cost was required for any kind of wireless connectivity.
The reverse side of the amp reveals a healthy complement of physical connections to join that improved USB input. On the analogue side there are four RCA ins and a balanced XLR; Cambridge has decided to omit a phono input, but an outboard phono stage such as the company’s own Alva models would make a fine partner for those looking to connect a turntable.
Power 80W per channel
DAC ESS Sabre ES9016K2M
USB input Yes
Hi-res 32-bit/384kHz and DSD256
Bluetooth aptX HD receiver built-in
Streaming Up to 24-Bit/48kHz
Meanwhile, the CXA81’s S/PDIF coaxial input will handle files up to 24-bit/192kHz, and its pair of optical connections take that up to 96kHz. You won’t find any digital inputs such as these on this amp’s main rival, the multi-Award-winning Rega Elex-R.
In terms of outputs, Cambridge Audio has included those for a pre-amp and subwoofer, as well as a 3.5mm headphone jack and space for two pairs of speakers, which can be played either separately or in unison.
Though the need to attach a separate Bluetooth dongle was marginally annoying, features and build were never the areas in which its forerunner, the CXA80, was lacking. While the impressive CXA60 won several What Hi-Fi? Awards, its bigger brother was never quite able to harness its extra power and translate it into as cohesive or expressive a performance.
Second time around, that is definitely not the case. There are many Cambridge Audio hallmarks here that make this CX amp broadly comparable with the tuning of its last iteration – only this time there has been progress in every regard.
From the opening bars of whatever piece of music we select, we’re greeted with the same powerful yet punchy, dynamic and astonishingly detailed presentation.
Confidence is key to the CXA81’s performance, hammering out staccato rhythmic patterns with assured conviction, snapping in time and allowing its expert handling of alternately loud and soft beats to lock in a groove. Above it, a full-bodied and expressive midrange deals out melodies that are given space to soar, yet still sound definitively part of a musical whole.
There’s a richness overall to the balance, too. This Cambridge is powerful and weighty in the low end, but lean and agile enough to dance around with the most excitable bass lines, while the treble is left plenty of headroom without sharpness or rough edges.
The CXA81 perhaps sounds a little forward, but its level of expression is such that it is sympathetic to more minimal, sombre recordings as well. Feed it a solo piano work or chamber quartet and it is only too pleased to show you its more caring, gentle side.
What really shines through though is a level of clarity that not only pips its rivals, such as the Rega Elex-R, but also makes them appear a touch cloudy. It is one thing beating this talented Rega amp for timing and dynamics, but to offer a more polished, insightful, even more mature presentation is a real turn up for the books.
The Cambridge Audio CXA81 sets a new baseline for integrated amps at this level. It’s a rare product that has the ability to make us switch off our reviewing brain and simply let us be wowed by the music. We only get to experience a handful of such products during the course of a year, and with the way in which the CXA81 disposes of its rivals, it’s fair to say Cambridge Audio has created one of them here.
And that’s only based on its sonic performance. Take into account its broad range of connections and features, and this is easily an amplifier that could last for as long as you wish – probably until you’re ready to spend a fair amount more on a significant upgrade.
Things often move fast in the world of hi-fi, but great sound never ages. If you have a system to make the most of the CXA81, it’d be folly not to scrawl the name of this multiple What Hi-Fi? Award (and Product of the Year) winner at the top of your list.
- Sound 5
- Features 5
- Build 5
See all the What Hi-Fi? Awards 2022 winners
Here are the best stereo amplifiers you can buy
Read our Rega Elex-R review
Additional comments for those who are considering purchasing this as a part of a CX stack including CXNv2 for a home/network audio system.
Having spent the last few days talking with Cambridge Audio, I think it's fair to say that, if you are thinking of getting this to go with the CXNv2 you will be disappointed by the lack of compatibility in the CX range.
There is a really nice combined remote control. The problem with it is that the volume control of the remote will affect both the Pre-Amp on the CXNv2 as well as the volume of the amplifier. Therefore, if you are intending on using the remote control, you will need to turn off the pre-amp settings on your CXNv2, but if you turn off the pre-amp you will have no (literally zero) ability to modify volume via any connected apps such as Airplay. StreamMagic may have very limited volume control, if you are lucky.
Despite the fact that the manual (Page 11 CXA81, third paragraph) suggests that the control bus will allow you to use apps to control the CXA61, this is apparently not true. The engineers have confirmed in writing that there is no ability for the CX series of amplifiers to respond to volume control via the control bus.
So, if you are looking for a device which is multi-room, network ready - you may wish to look elsewhere. If you are looking for an amplifier to go with your CXNv2, you may wish to look elsewhere (probably just buy a power amp and let the CXNv2 pre-amp handle volume).
Spoiler: It's really bad.
Paired with the CXNV2 you have a great looking stack that can hold it’s own sound wise with any streaming based system in the $2k to $5k range.
The DAC in the CXA81 is decen. On par with any stand alone DAC in the $100-$200 range. It scales well with higher end sources.