The sheer physical presence of this massive mono amplifier underlines the boldness of Linn Products' decision to launch it into a high-end market already well-populated with very capable contenders. The manufacturer says that the Klimax Solo 800 amplifier doesn't just exist to slot into an existing Linn system—instead, it will work with any top-quality ancillary equipment. The design brief was to set new standards by outperforming its rivals, achieving consistency and accuracy, and driving any loudspeaker effortlessly and with ultra-low distortion.

This is a bold boast for a fifty-two-year-old Scottish company, arguably best known for its turntables and active speaker systems. Can Linn succeed in rewriting the high-end amplifier rulebook? Standing a full 268mm high, 350mm wide and 412mm deep, with monster cooling fins running top to bottom, this behemoth pumps out a claimed 400W of Class AB power into 8 ohms (800W into 4 ohms and 1.2kW into 2 ohms), weighs a back-breaking 27kg and boasts quoted distortion figures of just 0.0004% (1kHz, 400W). It is bristling with top-quality components and high-tech ideas, including adaptive bias control, a 2kW switch-mode power supply and heat management techniques that let it run cool without using a noisy fan.

UP CLOSE

Let's look at those key design elements in detail. First, Adaptive Bias. Bias current is applied to an amplifier's power output transistors to help minimise the 'switching distortion' that occurs when the transistors that handle the positive part of the waveform hand over to those that handle the negative part. Bias is usually set just once by an engineer when the amp is made and can drift away from the ideal amount because of variations in operating temperature and as components age. It would typically be reset during a factory service, often years or even decades later.

While there are amplifiers that adjust bias to compensate for temperature, including Linn's existing range, Linn's Adaptive Bias takes it to another level. First seen in the 360 Exakt integrated speaker last year, the technology sees the Solo 800 measuring and sampling the current supplied to its eight pairs of transistors in real time. It uses a digital control algorithm to ensure that bias is optimal for each transistor, regardless of temperature or component age, so crossover distortion is kept to a minimum. The audio signal itself is never digitised, however, so it remains completely analogue.

In its quest to drive distortion to the lowest levels, Linn also uses dynamic, real-time monitoring and error correction via multiple digital and analogue feedback loops throughout the amplifier. A total of sixteen output transistors are employed to achieve its 800 watts, and the oomph to drive even the most difficult speaker loads. Nina Roscoe, project lead on the Solo 800 design team, explained that they use many transistors to reduce the current swing in each device, which she said ensures maximum linearity in the output stage.

Great care has been taken in the selection of other components, with heavy-gauge point-to-point copper wiring used where it was thought to improve the sound – mainly in the output cabling. One controversial aspect of the design is the use of a switch-mode power supply, which Linn has been fitting for many years. High-frequency switching power supplies have often attracted criticism, as many believe they generate noise and interference. In practice, they can be very quiet – I still remember the Sony Esprit TA-E88 and TA-N88 pre/power combo back in the late seventies, which used switching power supplies and gave Naim Audio amplifiers of the day a very hard run for their money. Chord Electronics also uses switching power supplies to great effect in its amplifiers, such as the Ultima integrated.

Linn's Utopik power supply features precision-regulated, independently isolated power rails, generating 2kW "while retaining speed and responsiveness", the company says. It operates well above the audio band, so any noise generated is said to be outside the range of human hearing. And, in any case, as Roscoe added, higher-frequency noise is always easier to filter out than the low-frequency noise generated by conventional linear power supplies. There is a large shield around the power supply in the Solo 800 that prevents coupling into the amp or its cabling and naturally rejects mains voltage fluctuations.

The Utopik supply also features 'soft switching', which uses an L-C resonant circuit to allow the voltage to fall to zero before switching occurs. This reduces the noise generated by the switching, while losses in the switches are dramatically reduced, improving efficiency. Another key goal for the Solo 800 design team was for it to run cool without needing a fan. Instead, it relies on natural aspiration and massive external heat sinks. Internally, convection draws heat into hidden vents before being expelled through oblong vents on the top of the case.

An amplifier at this price level deserves top-class ancillaries, so for this review, I used Linn's flagship Klimax DSM streaming preamp – although by no means is a Linn preamp necessary. When not playing Qobuz through the latest Linn App, I also used the superb Audio Note CDT-Five CD transport and DAC Five Special, through Russell K Red150Se speakers. Speaker cables were the Supremus Zr from QED, an Audio Note Black Pallas connected the transport to the DAC and an Audio Note silver cable from the CD transport to the preamp. Tellurium Q balanced XLR cables were used from the preamp to the power amps.

THE LISTENING

The Klimax Solo 800 delivers subtlety, delicacy and emotion – whilst packing an incredible punch on drums and percussion, serving up some of the deepest, tightest and most tuneful bass lines I have heard. For example, from the first few bars of Larry Carlton's A Place for Skipper, it was obvious that this huge Linn power amp was something special. Every last nuance of the acoustic guitar work was laid bare – how a note was shaped and sustained, its volume, and the voicing of his guitar was sharp, compelling and tonally beautiful.

Percussion was highly detailed, with great insight into every cymbal line and hi-hat opening and closing, while drums were dynamic and snappy. The bass line had superb grip, speed, and tunefulness with my pair of Solo 800s managing a weight and authority I had seldom heard before. I found myself able to listen effortlessly into what every musician was doing and how it all gelled into a cohesive whole in a way I have heard few amps achieve. This, to me, is the mark of a great amplifier – the special ones convey everything that's going on in the mix simultaneously and coherently whilst letting you focus in on anything you like.

I believe Bruce Springsteen's Darkness on the Edge of Town is one of the best-recorded rock albums of the seventies, with Racing in the Streets being my favourite track. The Linn amps bowled me over with the clarity and emotion in Bruce's voice. The simple piano on the intro had tangible space around it, with a sense of body as the hammers hit the strings. When the drum rimshot joined in, it was clean and sharp, and the subtle cymbal riff playing behind it was beautifully defined. Then the bass line kicked in and blew my socks off with its weight, tautness and tunefulness. It proved the Solo 800's mettle as an exceptionally accomplished performer from bottom to top. Indeed, it proved the best rendition of this track I've ever heard in my home system – or pretty much anywhere else, for that matter.

This Linn amplifier's genius is that it gets everything right; it is smooth and detailed, yet has excellent insight and a natural tonality. It is rhythmically animated and expressive in terms of dynamics, too – and the soundstaging is superb. It Didn't All Come True from pianist/singer/songwriter Ben Sidran's Bop City album was no exception, with the drums on the intro having great dynamic crack. The bass line was weighty yet fluid; never sounding overblown or slurred, it had a speed and coherence that I have rarely heard. This worked so well with the open and expressive vocals and fleet-fingered piano playing.

The Klimax Solo 800 is a seriously high achiever across the board, then. But its most significant skills, in my book, are its midband accuracy and agile bass. The monoblocks revealed breathtaking nuances of style and phrasing on the track So Amazing from Luther Vandross's Give Me The Reason album. To me, this is what makes Luther the best male vocalist ever. At the same time, Marcus Miller's bass line had weight, control, movement and character. I also really admired the Solo 800's ability not to make every bassline sound alike – it captured the individual character of each one, whether synth, guitar or double bass.

THE VERDICT

Whether it was George Duke's Brazilian Love Affair or Randy Crawford's You Bring the Sun Out, this amplifier proved hugely detailed, revealing, nuanced and insightful. Yet it also displayed sledgehammer bass, sparkling highs, and seemingly endless reserves of power. All of these factors make for an exceptional monoblock power amplifier. Of course, given its telephone number price tag, you'd expect it to be superb, yet it still surprises with an amazingly uncoloured and hear-through sound. Slot it into any great high-end system, and you cannot fail to be impressed.

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