Linn Klimax Radikal

Linn Klimax Radikal

The Klimax Radikal is Linn's reference motor controller and power supply for the Sondek LP12 — the component that sits outside the plinth and takes complete control of the LP12's motor speed, power delivery, and, where a Urika or Urika II internal phono stage is fitted, the quality of power reaching those electronics. It is built into a chassis that weighs nearly 14kg, machined from three pieces of solid aluminium, and mounted on high-mass stainless-steel feet with rubber ring inserts. This is not an engineering aesthetic — it is the physical expression of a design philosophy in which electrical and mechanical isolation are treated as inseparable from signal quality. A motor controller that sits on a shelf and vibrates, or that draws its regulated outputs from a compromised power supply, cannot do what the Klimax Radikal does.

Utopik Power Supply — Separate Rails for Separate Tasks

At the centre of the Klimax Radikal is Linn's Utopik power supply — a bespoke supply architecture with separate, dedicated, independently self-regulating output voltage rails for two distinct tasks: motor control, and power for any Urika or Urika II internal phono stage fitted to the LP12. The significance of this separation is architectural. A motor controller places demands on a power supply that are fundamentally different from the demands a phono stage places on one — a motor draws current in pulses as it rotates, creating supply fluctuations that a shared rail would transmit directly to the phono stage electronics. With independently self-regulating rails, each output is isolated from the behaviour of the other. The phono stage receives clean, stable power regardless of what the motor is doing at that moment.

FPGA Motor Control — Precision on Every Rotation

The Klimax Radikal's motor control unit is managed by an FPGA — a field-programmable gate array, a class of integrated circuit whose logic can be defined and refined in software, allowing Linn's engineers to implement a precision speed management system that checks and adjusts motor speed on every single rotation of the platter. The LP12's motor in Radikal configuration is a precious-metal brushed DC motor, replacing the standard LP12 synchronous AC motor. The DC motor's speed is not governed by mains frequency — it is governed by the FPGA's continuous closed-loop correction. Every rotation is measured; every deviation from the target speed is corrected before the next one begins.

This is not a speed control system that sets a reference and hopes the motor holds it. It is a system that verifies and corrects on a per-rotation basis, continuously, for as long as the record is playing.

Auto-Calibration — Speed Set at Power-On, Every Time

Each time the LP12 is switched on, the Klimax Radikal's speed management system auto-calibrates — establishing the precise motor speed for that power-on event, accounting for any variation in motor behaviour, ambient temperature, or mechanical condition that has occurred since the last session. The calibrated setting is saved to memory and recalled at subsequent power-on events, so the system builds a stored reference that reflects this specific motor's current behaviour rather than a factory average. The result is that the LP12 always begins playing from a correctly calibrated speed reference — not an approximation, and not a setting established months ago when conditions were different.

Machined Aluminium Chassis — Isolation as Engineering

The Klimax Radikal's chassis weighs nearly 14kg. It is machined from three pieces of solid aluminium — not cast, not pressed, not fabricated from sheet, but machined from solid billet, a process that produces a denser, more dimensionally stable structure with a more consistent resonant profile than any other manufacturing method. The high-mass stainless-steel feet with rubber ring inserts provide a two-stage isolation interface between the chassis and whatever surface it rests on: the mass of the steel feet resists the transmission of low-frequency vibration; the rubber inserts attenuate higher-frequency energy above that. The chassis itself, at nearly 14kg, is resistant to movement by virtue of its mass alone.

The combination of mass, material, machined construction, and isolated feet means the Klimax Radikal's electronics operate in a mechanically stable environment — which is the correct condition for a power supply whose job is to provide the most stable possible electrical output.

Technical Specifications

Who Is It For?

The Klimax Radikal is for LP12 owners who want the definitive Linn answer to motor control and power supply — those building towards, or already at, the highest levels of LP12 performance, where the precision of the motor control system is audibly the limiting factor. It is the power supply fitted to the Linn Klimax LP12 Turntable, and it is the correct partner for the Linn LP12 Selekt Turntable at the highest build level. It requires a Urika or Urika II to take full advantage of its dedicated phono stage power rail, and it is the component around which a reference-level LP12 system is organised.

For those building towards this level, the Linn Karousel Bearing Kit and Linn Krane Tonearm are the components to have in place before the Klimax Radikal's capabilities are most fully expressed. The Linn Klimax System Hub and Linn Exaktbox Sub represent the wider system components with which a Klimax Radikal-equipped LP12 is most naturally partnered.

Buying from Martins Hi-Fi

Martins Hi-Fi has been in Norwich since 1968. Elizabeth Gould runs the business today, and we stock only brands we have heard properly and stand behind.

The Klimax Radikal requires professional installation — motor replacement, Radikal mounting, cable routing, and speed calibration verification all need to be carried out correctly for the upgrade to perform as designed. We carry out the complete installation on our LP12 service bench and will not return a deck until every parameter is verified. If the Klimax Radikal is part of a broader LP12 upgrade — alongside a Keel SE sub-chassis, a Urika phono stage, or a tonearm change — speak to us first about the correct sequence and the most effective route to the build you are targeting.

When you get in touch, you'll be speaking with Dave and Chris — experienced specialists who can advise on this product and your whole system.

Contact us at info@martinshifi.co.uk, call 01603 627010, or WhatsApp on 07554 687137. You can read more about how we work on our Why Martins Hi-Fi page. We are at 85–91 Ber Street, Norwich, NR1 3EY.