Kleio K135 integrated amplifier
You might be thinking to yourself as you land on this review: What, another UK-made integrated amplifier, aren’t we already spoiled for choice? I must confess that when approached about reviewing the Kleio K135 I agreed but with some trepidation. However, having hosted a pre-production K135 in my system for a good few weeks I was happy to discover that my reservations had been groundless, as I learnt (spoiler alert) to greatly admire what this newcomer can do.
Let me first fill in some of the gaps in your knowledge (as there were in mine prior to this) about Kleio. Based in Faversham, Kent, Kleio is the brainchild of Garry Wise who formed the company in 2012 and started the process that has led to the K135 and its stablemate K105 preamplifier. Garry’s career has followed a different trajectory than many in the audio industry, as he has a technical background in IT. However he’s been working with experienced audio designers who have helped him to bring the products from concept to reality. According to the company’s website there was “a simple concept to design and build high-end audio equipment to make music enjoyable”. Easy to say, much harder to pull off. The two existing products will be joined in the near future by two power amplifiers, the K115 and the K125, with the latter being a dual mono design, both will be much higher power Class D amplifiers than the 65 watt K135. The Class D modules are from ICEpower, a division of Bang & Olufsen, and a name that is less common in this field that it was a few years ago but they enabled Garry to get the result he was looking for.
Let us now focus on the K135 and its vital statistics. My reviews almost always start with the unboxing, and my first impression of the K135 was of a solid, even hefty piece of kit. The front is elegantly simple: a single LED on the left hand side glows when power is on and to the right is the rotary volume control, which has almost a full circle of white LEDs around it to indicate the volume level. Then there is rectangle of black glass which looks for all the world like a screen but which simply carries the Kleio logo in a bold white uppercase font and below that is the model number. The receiver for the remote control sits behind this panel. A single button can be used to switch between the seven inputs, which are numbered 1-4 for the RCA connections with 5 and 6 being for the two balanced XLR inputs and input 7 which is marked MP3.
The case itself is machined from a solid billet of aluminium which must contribute significantly to the 12kg weight. The fit and finish of the K135 is exemplary. On the rear panel we have two sets of good quality loudspeaker output sockets which will accept 4mm banana plugs, spade connectors or even bare wires. Then come three sets of output sockets, one pair of balanced XLRs and two pairs of RCA outputs. Then come a pair of RCA sockets marked Record Link, followed by two pairs of XLR inputs and the aforementioned four RCA input sockets.
Stiletto power
Inside that handsome casework is of course where all the real work is done. Attention to detail is key here, and Garry and his team have clearly put a huge amount of thought into the K135. Relay switching and short signal paths maintain the integrity of the incoming signals, and in the engine-room what is described as a ‘high quality’ Class D power amplifier provides 65 watts per channel into an 8 Ohm load and 125 watts into 4 Ohms.
Bucking recent trends, the K135 has no digital inputs – it is a good, some might say old-school, integrated amplifier, whose sole purpose is to receive analogue inputs and drive a pair of loudspeakers. No doubt future iterations of the K135 may have digital capability included, but I like the fact that this version is more of a stiletto, driving into the heart of the music, rather than a Swiss Army knife with a bewildering array of blades and tools, most of which rarely get used.
A plastic remote control is supplied with the amplifier and is not at all over-cluttered with buttons, as so many are these days. In fact it has just eight of them, to turn the machine off and on, to dim the lights on the fascia, and a pair each to raise or lower the volume and to move up and down the input selection. Between those is a mute button. If I was being hyper-critical I might prefer the remote case-work to be wrought from the aluminium of the amplifier case, but this one does the job perfectly well.
As the K135 is blessed with two pairs of balanced inputs, I connected my Gold Note PH10 phono stage to one and my Yamaha CD-S3000 to the other. In addition to its disc playing capabilities the latter has a very capable ESS DAC section, into which I connected my television via a Toslink and my Auralic Aries Mini via the coaxial input. My Linn Sondek LP12, with a Dynavector XX2 cartridge fitted to the Ittok arm was used for vinyl replay. At the start of the review period I was hosting a pair of Dynaudio Contour 20i standmount loudspeakers, these were replaced towards the end of the review by my own Harbeth C7ES XDs, also stand-mounted. One last point before we get to listening to the K135 – it comes with a 5 year warranty from the company, which is longer than most and encourage’s faith in the design.
Listening to the K135
Once the installation was complete I started with one of my Qobuz playlists through the Aries Mini, to allow the amplifier to warm up after its journey from Kent to Devon. The first track on the list is from one of my favourite albums of recent years, Dave Alvin’s Eleven Eleven. Harlan County Line is a fine piece of Americana, with Mr. Alvin’s rich but gruff baritone telling us a tale of love lost and found, with his own guitar (a road-battered Fender Stratocaster) and his band adding depth and drama. Even cold, the K135 brought the music to life through the Dynaudios and whetted my appetite for what was to come.
I allowed the music to run on for about an hour then went back to that first track. An initial slight leanness to the sound had gone, and Alvin’s voice had a terrific immediacy to it, drawing me into a deep and utterly convincing soundscape, where I was standing just in front of the low stage in the Kentucky bar where the band was playing. I adjusted the volume so that just over half the LEDs around the control knob were alight and simply lost myself in the music. The notebook was set aside as I became engrossed in the wonderful effortless drive on song after song.
The next day I got the LP12 spinning and cued up my vinyl copy of Eleven Eleven. Oh, my, goodness! I had thoroughly enjoyed its digital counterpart the day before, but this was even more engrossing. The K135 delivers a wonderfully realistic midrange but what surprised me more was the quality of the low registers. The Contour 20is have very good low frequency response, especially given their modest dimensions, but what impressed me here was the precision of those low notes. Bass was well controlled but oh so tuneful.
With a slight change of genre, I turned to my six disc Beach Boys compilation album from 2022, the reworked Sounds Of The Summer. The first track on the first side is a stereo version of the classic California Girls. Through the K135 and Dynaudio combination this was audio dynamite. There was plenty of low end energy but the harmonies absolutely thrilled, as one classic track followed another, with a sound as fresh as if it had been recorded last week rather than half a century ago. Which made this more of a contemporary experience rather than a walk down memory lane.
Switching to jazz, which is commanding more and more of my listening time these days, I started out as I often do with Bass On Top by the Paul Chambers Quartet on the Blue Note Tone Poet reissue from 2021. The four players were led by bassist Paul Chambers, who was on a day off from his regular gig with Miles Davis. Guitarist Kenny Burrell, pianist Hank Jones and drummer Art Taylor were also very busy men, but the music the four of them laid down that day showcased each of them and still thrills all these decades later. Here the K135’s bass prowess really shone through. Whether bowed or plucked, Chambers’ instrument sounded totally realistic – never over-emphasised but clear and intensely musical. The rhythmic drive of the music was perfect, and the timing of the system was terrific.
Breathless
One evening Mrs K and I settled down to watch Top Gun: Maverick and the K135 delivered the soundtrack with terrific punch – the aerial scenes left us almost breathless, thanks in no small measure to sounds that accompanied them. Yet when calmer moments arrived and characters actually indulged in dialogue it was absolutely crystal clear.
Switching to classical music it was quickly apparent that the K135 can reproduce notoriously difficult sounds, such as solo piano, with real finesse, conveying not just the sound of the instrument but a real sense of the acoustic space in which it was recorded. Similarly with choral music, massed voices can thrill as much as the soprano and other soloists. I thoroughly enjoyed listening to the Dunedin Consort’s rendering of Handel’s Messiah, for instance. It seemed as if every tonal nuance faithfully reproduced.
After the Dynaudios went home I reinstated my Harbeth C7ES XDs on their HiFi Racks Fortis open stands. These loudspeakers are pretty amplifier agnostic, in that I have never heard them sound less than excellent with any of the many amplifiers with which I have paired them. Driven by the K135s I really felt that they were giving their very best, tempting me to crank up the volume to fairly high levels without detriment to the sound quality. With the volume dial somewhere between two thirds and three quarters towards maximum I had to stop, not because the equipment was distressed but because it was just too loud even for my ears to cope. I got the distinct impression that in any typical living room (ours is about 15×12 feet) the K135 has more than enough power on tap to drive all but the most recalcitrant loudspeakers. Certainly with both the Dynaudios, rated at 86dB/4 Ohms and the Harbeths, rated at 86dB/6 Ohms, there was never a hint of a problem for the K135.
For the sake of completeness I switched both my source units from XLR to single-ended RCA interconnects, and I am happy to report that these sound equally as impressive as their balanced counterparts. If your sources do not have XLR outputs you will not be in any way disappointed with the K135.
Conclusion
I think by now you will have gathered that I really enjoyed my time with the Kleio K135. I love its unashamedly analogue nature, its build quality and above all its sonic capabilities. It combines many of the attributes which I value in an amplifier, with all the pace, rhythm and timing one could wish for, combined with a pleasantly understated aesthetic and what feels like a very high standard of build quality. It is ‘voiced’ as well as any amplifier I have heard, including several that cost a great deal more.
As of yet, the Kleio brand has only a few dealers here in the UK, but I hope and expect that more will clamour to take it on as news spreads and demand increases. The K135 deserves a place at the top table alongside better known competitors, and cannot fail to impress all those who seek it out for audition. I salute Mr. Wise for his dogged determination to bring his vision to reality, but even more for the incredible quality of this first foray into a very competitive market. The five year warranty is also a good indication of the self-belief behind the Kleio brand. If reading all this has piqued your interest and you are considering an amplifier upgrade, I think the extra effort in tracking down a Kleio dealer and arranging an audition would be very worthwhile – you will be very glad that you did.