Kleio K135

Kleio K135 integrated amplifier review

It’s likely you’ll not have heard of Kleio, and that’s part of this relatively recent British hifi company’s ethos, as its approach has been to evolve at its own pace, letting its reputation grow within hifi circles organically.

With a name derived from Greek mythology, Kleio Audio’s story starts back in 2010 when company founder and MD Garry Wise was looking to build his own headphone amp. This idea quickly snowballed into developing a fully fledged integrated amplifier and by 2015, its first two models were set for release as part of its K1 series, with the K105 pre (£4,400) and K135 (£4,750) integrated, the latter being under scrutiny here. Speaking to Garry it’s clear he’s driven by two clear goals which sit at the heart of Kleio’s DNA – a love of hearing music at its best in real world surroundings and a drive to grow a brand that can stand toe to toe with the leading hifi brands of today.

Kleio K135 amplifier

Modern styling and expert finish befit an amplifier in this price bracket

Read our Spotlight on Kleio Audio interview with Company Founder Garry Wise

Of course building a dedicated hifi amp at this level is no easy feat, and after experimenting with a number of topologies and designs, Kleio evolved its own custom preamp that’s married to a dedicated ICEpower Class D power amp section, offering 65W into 8 ohms and 125W into 4 ohms. Not that you’d guess at the K135’s Class D internals with a weight of 12kg all in, which you’d typically expect for a beefy Class AB design.

Kent chic

The K135’s heft is partly accounted for by its solid aluminium casework which oozes class, and puts the build quality of many longer established brands’ mass produced hardware to shame.

Kleio internals

Short signal paths and clearly laid out internals within the K135, with its transformer given plenty of space. Digital module will live above the main PCB (top of image)

Finished in metallic silver the K135 sports design cues that make it attention grabbing in a stylish and subtle way, from the faceplate sides’ opposing curves to its recessed footprint. At a glance I’d have pegged this as Scandinavian in origin, alongside the likes of Soulution and Primare, rather than being handmade in Kent (and proud to be so).

Future upgrades

Connections are kept purely analogue for now, with inputs spread over four pairs of line-level RCAs and two sets of balanced XLRs. There’s also a 3.5mm jack, although this is set to be replaced with an optional digital module in the near future.

Outputs are equally well considered, including fixed and variable level pre outs (RCA) alongside balanced, allowing you to add one or more power amps further down the line (including Kleio’s own, with stereo and mono models currently in the works).

Kleio K135 rear panel

A raft of analogue connections spread over four RCA and two XLR inputs, with outputs shared over variable (XLR/RCA) and fixed (RCA). A 3.5mm jack will offer an optional digital input in future models

With no apps or digital headaches to contend with, set-up is as straightforward as you’d expect. Once hooked up a quick depress of the large volume knob brings the amp to life, denoted by an LED doing a quick cycle of the volume dial which is a nice touch. When operational, these LEDs remain solid up to your chosen volume level, showing you at a glance what the amp is set to. The only other front panel control is the select button to the right of the branding. Being so intuitive to use has meant the K135’s front panel labelling is kept to an absolute minimum and for input only, making it clutter free.

A branded black plastic functional looking remote control is also supplied, although a matching one in silver alloy would perhaps be a more fitting operating partner, but it gets the job done and brings with it a mute button and option to dim the volume display lights.

Kleio K135 with remote

Branded remote is a practical inclusion, offering mute and a dim option for the volume level LEDs


Nestled up against my Primare NP30/NP5 streamer, R32 phono stage and VPI Scout 21 deck, the Kleio looks right at home driving my legacy Dynaudio Focus 260 loudspeakers.

Streaming a 24-bit/44kHz file of Bright Eyes’ Easy/Lucky/Free from Qobuz reveals the Kleio to be blessed with a sense of energy that brings the track to life with palpable realism. What’s also clear though is how nicely balanced this amp’s dynamics are, they’re not dialled up shot in the arm stuff that many of the Class D breed can possess, which can sound initially arresting while soon becoming fatiguing.

Kleio top view

Measuring just 405mm wide by 380mm deep, the Kleio is more compact than many amps at this level. Ours came in a sumptuous silver finish, with grey, black and custom finishes also available

Instead there’s more than enough bite to make you sit up, but this is nicely offset with a sense of ease and richness that shows how well the K135’s internals have been engineered for both articulation and longterm listening. The track’s punch of the percussion sounds crisp and refined, while the vocals and vibrating lower bassline have more than enough organic resonance to bring out the emotional intent.

Dial in Blondshell’s Olympus from her self titled debut at 24/96 and the Kleio renders the intro’s smooth groove with the laid back nature of a bourbon by the fire, allowing the bassline and drums to breathe within the soundstage, surrounded by a sense of plenty of air and space. And once the extended chorus kicks in at around two and a half minutes in to the track, the Kleio lets the raw nature of Sabrina Teitelbaum’s heartfelt vocals erupt like a lion’s roar if you’d stamped on its tail. And this underlines what the the Kleio is all about, by offering a transparent window to let the music do the talking without adding a filter of its own.

Kleio with Dynaudio Focus 260

Holding its own with my reference Dynaudio and Primare partnering gear

Spinning up a vinyl pressing of Ben Howard’s Nica Libres At Dusk from his Noonday Dream album allows the Kleio to really open up as the chord shifts kick in and high frequency strings soar. Bass is also well articulated and with nice levels control in comparison to many of the Class AB breed that favour scale and volume over precision and timing, traits my Dynaudios relish from the Kleio with their tendency towards bass bloom.

In summary

That this is Kleio’s first integrated amplifier is quite something, given the  articulation the K135’s sonics are blessed with. Add to this its stylish looks, solid build, ease of use, compact proportions and five year warranty and the K135 becomes a very easy proposition to live with.

If you’re in the market for a quality integrated amp without following the herd, make sure the Kleio is on your essential audition list.


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