Klimax Solo 500 is Linn’s complete redesign from fundamentals of their most successful amplifier ever – Klimax Solo. They have maximised the potential of every cubic millimetre within its machined-from-solid enclosure to create a product that is an improvement over its legendary predecessor in every conceivable way – one that, crucially, still boasts a compact form factor.

With Solo 500, Linn’s latest top-tier innovations powerfully coalesce into the best compact monoblock amplifier they have ever made. The synergistic combination of Adaptive Bias Control and sophisticated hybrid cooling matrix with intelligent fan management, results in a Class AB amplifier that is far greater than the sum of its parts, yet remarkably smaller than its counterparts.

Linn’s engineers have expertly miniaturised and arranged their flagship amplifier and power supply technologies inside its sleek and minimalist casework to ensure that Solo 500 is a staggering upgrade. It’s the ideal drop-in replacement for existing systems which feature original Solo or 3rd-party amplification. Its neat size lends itself particularly well to active setups and scenarios where space is at a premium.

The holistic approach to its design has culminated in an amplifier that performs optimally from the moment it’s powered on for the first time, and throughout its long lifespan; an amplifier that can be driven hard for protracted listening sessions of wildly dynamic material, and yet remain silently cool; an amplifier with huge available power, devastatingly low noise floor, and eighty-five times lower distortion measurements than the one it replaces. Solo 500 is a small amp, with big credentials.

Adaptive Bias Control

Adaptive Bias Control is Linn’s groundbreaking in-house technology which first debuted in 360 Exakt Integrated loudspeakers, was then optimised for inclusion in Klimax Solo 800, and is now a critical element of Solo 500’s prodigious performance. It ensures optimum output performance from their latest crop of high-end amplifiers, under any conditions, and for the duration of the product’s life.

Conventional Class AB amplifiers require the application of bias current at their output stage to mitigate transistor crossover distortion. This remedial bias current is keyed-in only once, manually, by the engineer who builds the product. Due to variations in manufacturing tolerance of individual transistors, fluctuating temperature during use, and component age, this estimated bias current begins to wander far from ideal – and continues to do so over the amp’s life – resulting in ever-increasing levels of audible transistor distortion.

With Adaptive Bias Control, Linn solves this issue. At any given moment during operation, the optimum bias current is established intelligently within Klimax Solo 500 in real-time. The current supplied to each of the eight output transistors is measured, sampled and digitised continuously, before being passed to a powerful FPGA processor, which calculates the requisite bias at that precise moment. The FPGA simultaneously implements a digital control loop to adjust and hold bias current at its measured optimum for the transistors.

Solo 500, therefore, is persistently measuring and adjusting its own output to be ideal at all times; at any temperature, regardless of volume or sudden dynamic changes in the music signal it receives, and for the entirety of its long life. Crucially, this means that Solo 500 will perform identically to its neighbours, thus ensuring flawless and consistently balanced performance between all amplification in the system — permanently.

Adaptive Bias Control conclusively solves the primary performance and consistency issue otherwise attributed to Class AB amplifier design. It’s a key factor in Klimax Solo 500’s devastatingly low noise floor. As a result of its implementation, Solo 500 measures eighty-five times lower total harmonic distortion and noise than its predecessor under typical listening conditions.

Hybrid Cooling Matrix

Klimax Solo 500 features a brand-new thermal management system—a hybrid cooling matrix—which ensures that the amplifier can adapt in response to the demands placed upon it, remaining cool and whisper-quiet at all times.

All internal electronics are mounted directly, upside-down, to a sub-chassis. Comprising a highly conductive block of hard-anodised aluminium mounted to a thermal plate, this sub-chassis draws heat away from the electronics beneath and is isolated from the amp’s main casework.

The thermal plate is bedecked with a series of machined fins. Designed and optimised using sophisticated simulation software, these fins form a labyrinthine network of precisely measured channels atop the thermal plate. At this stage and under these conditions, the fins naturally radiate heat upwards and out through precision-cut gills in the amplifier’s upper casework. This natural convection and radiation system is ideal for keeping Solo 500 cool during everyday listening sessions.

When the amp is pushed harder, however, this is where Solo 500’s hybrid cooling matrix gets really clever. In order for the amp to remain safely cool, and thereby maintain optimum performance, efficiency and preservation of electrical components, Solo 500 must now switch to active cooling by way of two internal fans positioned deep within the product. The fans force cool air around the network of channels on top of the thermal plate – the hottest part of the product.

Typically, when an amplifier is driven loud, its internal temperature will increase to the point where, for safety, integrated fans will spin up to speed to draw cool air into the amp. The more cooling required, the faster the fans spin.

To tackle this problem, Linn has designed an intelligent fan management system for Solo 500. Monitored and controlled by an FPGA processor in real-time, the required fan speed is determined by a combination of both the measured internal temperature of the amplifier and the input audio signal. This ensures that the fans run inaudibly at the lowest speed possible at any given time, whilst providing ample cooling to avoid overheating and thereby maintain ideal performance, listener experience, and efficiency.

Utopik for Solo 500

The hybrid cooling matrix’s effectiveness is aided by a specially optimised Utopik power supply. Auto-voltage rails ensure that output from Utopik also adapts to the audio signal itself, only delivering the necessary power dictated by what’s playing and its volume. Less superfluous energy is generated, which would otherwise be wasted as heat. As a result, efficiency is improved, baseline internal temperature is minimised, and Solo 500 consumes less electricity in general.

Build & Design

Solo 500’s overall aspect is one of minimalist and sophisticated beauty. Upon closer inspection, its machined-from-solid casework is punctuated by finely designed and characterful details.

With a seamless construction composed exclusively of three aluminium pieces—baseplate, enclosure and rear panel—Solo 500 gives the impression of a congruous whole aluminium mass.

The shape of its face is new; a modern evolution of the signature Linn ‘smile’. Below the smile, a completely flat face, whilst the top half is machined with a compound curve on two axes. This precision-machined detail lends Solo 500 character; in specific lighting, there is a pleasing variety of reflection. A variable fillet cut in the aluminium grows towards a chamfered edge and eye-catching centrepiece; a back-lit Linn badge in the centre of a miniature roundel, with radial-grooved chrome trim detail and a steel outer ring.

Gentle animations of the LEDs behind the mini-roundel communicate the amplifier’s status. When operational, white light diffuses, producing a soft glow around the outside of this attractive and fine detail. The badge assembly also has depth; reflecting light dynamically when viewed from different positions. Each amp in the system will reflect light and create its own shadows, contributing to Solo 500’s characterful statement aesthetic.

Summary

With a combination of reverence, passion, creativity and innovation, Linn has created a worthy successor to the original Solo. Klimax Solo 500 is an amplifier with big credentials, and reference-level performance, in a remarkably compact form.

With a characterful and precision-machined design that complements its function, hybrid cooling matrix with intelligent fan management, and Adaptive Bias Control, Klimax Solo 500 has had every cubic millimetre optimised to render it a staggering improvement over the legendary amp it replaces.

It’s the best compact monoblock amplifier they’ve ever made.