Linn Klimax Twin Stereo Power Amplifier

Linn Klimax Twin Stereo Power Amplifier

Constantine Soo

18 March 2003


Output Power: 230 Wpc (4 Ohms), 100 Wpc (8 Ohms) Unconditionally stable into all loudspeaker loads
Peak Output Voltage: 46 V
Frequency Response: 7 Hz to 35k Hz (-3 dB)
Harmonic Distortion: >0.02%
Input Impedance: 7k @8 Ohms, RCA and XLR
Gain: 28.6 dB (RCA), 22.6 dB (XLR)
Input Level (Clipping): 2v balanced, 4v unbalanced, 1.67V RCA, >150uV Signal sensing threshold
Inputs: WBT RCA (switch position in), XLR (switch position out)
Pin Connections: Inner: Hot, Outer: Cold (RCA), Pin 1: OV, Pin 2: Hot, Pin: 3 Cold (XLR)
Power Supply: Switch Mode
Power Consumption: 18W Standby, 39W Typical Operation, 1000W Maximum
Dimensions: W 13.8 × D 13.9 × H 2.3(inch)
Weight: 20 lb
Price: $9,000


Linn Products Ltd, Floors Road, Waterfoot, Glasgow G76 0EP, Scotland
Phone: +(44) (0) 141 307 7777
Fax: +(44) (0) 141 644 4262

Linn Incorporated
4540 Southside Boulevard, Suite 402, Jacksonville, FL 32216
Phone: 904-645-5242
Fax: 904-645-7275

Klimax Twin is the stereo version of Klimax 500 Solo, Linn’s latest amplification statement. The Twin is identical in dimensions and weight as one monoblock 500 Solo with a little less than half the output capability. 

The Linn’s accompanying, ring-bound 24-page Owner’s Manualrivals the readability and resourcefulness of manuals I have read to date in contents and layout, and can easily become a collector’s item. Among the eight sections in the Manual, namely “Introduction”, “What is it?”, “How does the Klimax work?”, “Installation”, “Operation”, “Specifications”, “Guarantee and service” and “Index”, the third section alone in it’s 10 pages can provide a good hour of engaging discussion of the technologies of the Klimax. 

The major significance of the Klimax Twin’s switching power management technology was its dispensing with modern solid core and toroidal transformer technologies. According to the Manual, the KT’s primary form of switching power was developed by the computer industry. The process of adapting this technology from computer applications to high-end audio was a major one. Linn claimed that its fully developed switching power supply harnessed potential superiority over conventional methods in its compactness, high efficiency, fast response, in addition to good mains input, good load tolerances, low acoustic noise, low material use and environmental friendliness. More importantly, in terms of marketing and sales, Linn’s industry norm-defying vision of a slim-lined amplifier was also an exceptionally bold one.

On the front of the Klimax Twin there is a blue operation indicator inside the “stylus-in-the-groove” smiling-face fascia at the center. All input and output terminals on the rear were arranged unbelievably within the confinements of the chassis’ shallow height and recessed under the top panel. Divided by the central heat exchanger, the switchable balanced and RCA inputs are located on the left rear panel. An IEC receptacle, power switch and speaker binding posts are on the right. Although using oversized power cords and speaker cables, such as Virtual Dynamics’ Nite interconnects and speaker cables was possible, the oversized VD hoses made system reconfigurations laborious. In addition, the triple-run makeup of VD’s AC main was even thicker than its interconnects and speaker cables, and thus could not be fitted within the space constraints of the KT’s rear panel. In this case, the Granite Audio #560 AC Cord was used in alternation with Linn’s stock cord.

The central heat exchanger represented the other most predominant visual feature as it ran through the center top chassis from the front to the rear, allowing heat to rise from within the Klimax. The exchanger also had a small, internal fan near a rear opening for forced air convection cooling when necessary. 

Finally, the KT’s idling power consumption of 18W provided the most profound statement in amplification evolution in contrast to the 600W power consumption of my Reference Line Preeminence One Signature during idling. This thoughtful design mutes the output after 10 minutes of inactivity and puts the KT in standby mode. With the negligible power consumption in standby, I kept the KT in optimal operating mode by leaving it on during most of the week, along with the power-on 47 Lab digital front end and a muted Audio Note M3 preamplifier.


The Klimax Twin’s rated 4 Ohm output of 250 Wpc made it a universal amplifier for all speakers at my residence, hence the KT was rotated among all of them, with the 84 dB/3.5 Ohm Apogee Duetta Signature being the least efficient, and the 104dB/8 Ohm Klipschorn the most efficient. Other speakers included the 90dB/4 Ohm, 3-way 4-driver, floorstanding ELAC 518, 90dB/6 Ohm Genesis VI, 82dB/8 Ohm Celestion SL700 and the 94dB/8 Ohm Audio Note AN-E SEC Silver loudspeaker systems.

Digital front ends were my 47 Lab Flatfish and ProgressionRedbook CD system and the Sony SCD-777ES SCD Player, with each of them plugged into a separate medical grade AC power isolation device “ISO” for line conditioning. The Audio Note M3 tube preamplifier served at the helm with Virtual Dynamics Nite series cable system applied throughout. 

Among his other great symphonies, Anton Bruckner’s Symphony No. 7 [Deutsche Grammophon “Karajan Gold” 439 037-2] is arguably his most brilliant and involving one for its continuity and originality. Via a 1990 reading by Maestro Herbert von Karajan as performed by the Berlin Philharmonic, the music does not contain a fleeting moment of dullness or repetition in any movement which tends to sprout up in his other symphonies. The composer rose to the challenge and instilled this large-scale work with bold but intricate ideas throughout, creating tremendous suspense. 

The Klimax Twin’s conveyance of this Redbook CD’s formidable scale via the $20,000 Audio Note AN-E SEC Silver was as intimate as it was colossal, as the orchestra’s distinguished, splendorous signature brass and sonorous strings were impressively communicative in forging a formidable, collective scale. While the Linn/AN combo was portraying the upward extending flares of the horns and the perfectly unified, blazing violins, the entire frequency spectrum traversed in such grace that there was not a trace of the characteristic forward or upward transistor bite. 

This very unconventional persona of the Klimax Twin set itself apart from all other transistor amplifiers that I’d used in this digital age in that even as they all strove to deliver a sound with as integral a spectrum and extended a bandwidth as possible, none approached the level of sophistication from the KT. The Linn’s sonic makeup had startling congruity of the Audio Note M3 tube preamplifier’s tonal abundance, with an unusually firm grip on maintaining frequency purity that seemingly inferred an examining intelligence from within the KT. This finesse from the KT became even more startlingly appreciable in its coupling to relatively affordable cone speakers, such as the ELAC 518 and the Celestion SL700, when the amplifier invoked unprecedented spectral purity in instrument characteristics sans the sporadic resonance and ringing common from high-volume transistor amplifier applications. 

Using the AN speaker in an experience of Klimax Twin’s amplification of the Seiji Ozawa SACD 2002 New Year’s Concert [Philips 470 615-2 PSA] was another cause for celebration. Knowing the Audio Note designer’s expressed forbearance in using his speakers to reproduce non-musical special effects, I was nevertheless pleasantly surprised by the realism of audience applause as accorded by the combo. Live effects aside, the Philips SACD’s dynamic was so dramatic, along with tonalities so flamboyant and dimensionality so specific that it was as if oxygen in the listening space was purer. I reckon that the Klimax Twin implementation of the Linn Switching Power pushed the envelope of amplifier/loudspeaker interaction. As much credit as the Sony DSD sound-processing technique might deserve, the SACD would never sound this good without the paramount augmentation of the joint forces of Linn’s Klimax Twin and Audio Note’s AN-E SEC Silver.

Driving the inefficient, all-ribbon Apogee Duetta Signature, the Linn KT maintained its stability in substantial output of current during the climactic passages of the Anton Bruckner symphony and the Philips SACD. The immense radiating surface of the flat-panel speakers yielded stirring sonics of such vigor that although the Apogee’s were tonally less evocative than the AN-E SEC Silver’s, the approaching sound waves produced by the ribbons were wholesomely encompassing and intimately enveloping.

A noteworthy, fatigue-purging 2 hour-succession of the two discs via the Apogee’s prompted the middle part of the KT’s top chassis to become extremely hot while still touchable, indicating that it was working at peak condition driving the 84dB/3.5 Ohms Apogees. Yet, the internal cooling fan was never engaged. Knowing Apogee’s requirement for high current amplification, the fact that the 2.3 inches thin, toroidal-lacking KT was able to drive the Apogee’s to extremely high volumes with ease and finesse defied established doctrines in amplifier choices.

Also noteworthy were the sessions the KT’s spent with the 104dB/8 Ohm Klipschorn, which bore witness to decisive dynamics set against an expansive soundstage, with delicate instrument harmonics manifested, despite the K-horn’s relative weakness in tonal depiction. Although the KT only needed to supply the K-horns with an infinitesimal fraction of its output capability, the amplifier’s utmost operational quietness also complimented the horns’ extreme sensitivity fittingly. 

The Klimax Twin also emancipated the $3,700 ELAC 518’s remarkable JET tweeter in a showcase of airy and full-bodied orchestral strings, accompanied by undaunted double bass rumbling in a spectacularly extended top and bottom-end ovation. By summarily harnessing the potentials of the $3,700 ELAC 518, the Klimax Twin also concurrently reaffirmed the strengths of the ELAC.


The Linn Klimax Twin’s class-D, solid-state dispositions induced from the incredibly resolute Audio Note AN-E SEC Silver Loudspeaker an unexpectedly coherent, expansive and refined spectral presentation with a most notable and consistent iteration in top-end finesse. Although the KT did not transcend renowned SET design’s attributes of vivid tonalities and particularly communicative midrange, the $9,000, slim-lined amplifier rallied prestigious prowess nonetheless in sustained outputs, exerted extraordinary spectral uniformity from speakers and imparted rousing tonal articulation yet to be heard from other elite amplification designs. 

In fact, the solid-state Klimax Twin’s subtle but resounding tonal flamboyance and vibrancy fundamentally purged the common transistor-ridden artificiality from music reproduction, and the Linn’s sonics were in the kinship of the previously reviewed 
47 Laboratory 4706 Gaincard S Integrated Amplifier. These two elite products’ handling of instrument harmonics reconstituted one’s faith in the solid-state methodology. 

The Linn’s exemplary ease and grace set itself apart from the Reference Line Preeminence One Signature transistor powerhouse. As the house-warming, high-biased, class-A titan Reference Line charged to reproduce with eminence and force when called for in the company of progressively inefficient speakers, such as the $9,500, 90dB/6 Ohms ribbon-tweeter Genesis VI, the $3,700, 89dB/4 Ohms ELAC 518 and the $4,500, 86dB/4 Ohms Apogee Duetta Signature, the KT not only handled each and every one of the speakers with an equally mighty stance with profoundly elated swiftness and style, it also seemingly polished each musical note. 

Thus, investing in the KT is akin to purchasing a $7,000 Audio Note or Koetsu cartridge, in which the amount of investment is assured by a return in quality, despite the relatively modest amount of mass. The Klimax Twin’s extremely slim dimensions and meticulously designed chassis culminating into a sculpture-like fashion statement notwithstanding, it had such sonic capabilities that it could well be a startling member of an emerging design concept and effort fundamentally unique to the U.S. audience, and perhaps one infused with aristocratic tastes. 

Amplifier manufacturers past and present have all ventured to create a revolutionary product at some point in their product offerings, and many of today’s prestigious, forefront transistor amplification companies have endeavored to expand their amplifiers’ ultra-bandwidth sustainability with the arrival of high-resolution formats. Yet, the progressive non-linearity of many solid-state amplifiers during stressful outputs continue to be one of the factors provoking distaste from many audiophiles, prompting them to turn to valve amplifications eventually. 

With the unprecedented sophistication in sound and finesse in execution, Linn’s Klimax Twin may qualify as a universal amplifier to audiophiles in its musicality and power. And to the generation growing up with electronics operating with this compact but potent power management system, the existence of present day’s high energy-consumption, air conditioner-sized behemoths powered by large transformers would become incomprehensible. I reckon that no other amplification innovations would be as capable of creating the far-reaching ripple effect as with Linn’s Switching Power technology.

The $9,000 Klimax Twin is unique in its avante garde technological marvels in a classy design statement, not to mention a sonic presentation as resplendent with audiophilia criteria as it is rich in musicality. Traversing in the same spirit of Dr. King, I envision a world in which all amplifiers are not judged by their external dimensions; but by the level of excellence they are capable of.

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