Linn LK2 Stereo Power Amplifier
A black, purist Scottish power amp that the record barely remembers, and the people who own one tend to keep it.
Overview
The Linn LK2 is a stereo power amplifier built by Linn Products in Scotland. It is black and stripped of everything that isn't amplification. No volume control. No preamp functions. No source switching. It is a pure power amplifier, meant to be driven by a separate preamplifier, most naturally the matching Linn LK1. That is how the two were sold and how most surviving pairs are still used. One Finnish owner used the word mokula, a compact box, and described it flatly as "a pure power amplifier." That is about as much characterization as the model has attracted in nearly four decades.
What makes the LK2 interesting to a collector is less what it does than what happened to its paper trail. Someone has asked "what is the Linn LK2?" on an audiophile forum, so the model clearly didn't register much outside Linn's own customer base. HiFi Engine, hifidatabase.com, manuals.co.uk and ManualMachine all carry pages for it, and the service manual survives. The published specification is a mess, though. HiFi Vintage and Spring Air ("2x 60 watt") report 60 watts per channel into 8 ohms, while a Reverb listing gives 50Wpc into 8 ohms and 100Wpc into 4 ohms. The 60W figure on HiFi Engine sits under an "LK275" sub-heading, so even that attribution is shaky. The LK2's rated output is reported at approximately 60 watts per channel into 8 ohms, with a competing 50W/100W figure in circulation, and no manufacturer document in the archive settles it.
Dimensions are just as thin. hifidatabase.com gives 260 × 75 × 260mm (W × H × D), and no second source backs it up, so treat it as approximate. Gain is quoted at 28.5dB and output voltage at 240V, both from a single eBay UK listing, which is weak evidence at best. Spring Air's description of the amp as "very impedance stable" is a marketing characterization, not a measurement. None of this makes a confident spec sheet, and the archive would rather say so.
Key Features
Pure Power Amplifier — No Volume Control, No Preamp Functions
The defining design decision is subtraction. The LK2 has no volume control, no input switching, no phono stage, no tone controls. It is just amplification meant to be driven by a separate preamplifier. In practice that means the LK1, which Linn sold as the matching preamp and which shows up alongside the LK2 in listing after listing. For a period Linn system, the pairing is the obvious one. Anyone hoping to run the LK2 straight from a source is out of luck, because it won't work.
Black Purist Chassis
Spring Air calls it a "black purist power amplifier," and that's the whole cosmetic story as far as the record goes. The 260 × 75 × 260mm dimensions, if hifidatabase.com has them right, describe a squat, roughly cubic box, shallow enough to sit on a shelf and deep enough to house a serious power supply. It is a black box that amplifies.
Impedance Stability
Spring Air's claim that the LK2 is "very impedance stable" is the one performance characterization that survives in the literature. An amp that holds its output across varying speaker loads behaves predictably with real speakers rather than bench resistors. Whether the LK2 lives up to the claim is unverified, but it's the attribute Linn's own marketing chose to lead with.
Per-Channel Trip Protection
The LK2's service documentation describes a trip circuit for each channel, designed to protect the amplifier board and the speakers from a potentially damaging over-current situation. If the amp senses it is drawing too much current, it shuts down the affected channel. Causes include a faulty speaker with an internal short, speaker cables shorted together, very loud music, or a faulty preamp. Once a channel trips, it stays in trip mode until the amplifier is switched off for up to 20 minutes. The manual is emphatic that owners should leave it off for the full period, because if it's powered up too early the trip capacitors recharge and restart the clock. Linn's service notes record customers who cycled the amp impatiently, concluded it had a permanent fault, and were wrong.
Historical Context
The LK2 appears to have been part of Linn's solid-state amplifier line of the mid-to-late 1980s, but that phrasing is the research record's own hedge, and the same sources explicitly note that no production years are recorded. Treat the era as probable rather than confirmed. What is solid is the company it kept. The LK2 was marketed and used as the matching power amplifier to the Linn LK1 preamplifier, and Linn's service manual covers the LK2, LK-275 and LK-280 together, so the three shared a service lineage even if their exact lineup positions aren't documented.
The surrounding family is better recorded than the LK2 itself. The LK1 preamplifier carried a list price of $1,050, and the LK280 power amplifier was rated at 80 watts per channel into 8 ohms. Both are reported in Audio (April 1989, p.91). Those figures belong to the LK1 and LK280, not the LK2, and should not be read across. Where exactly the LK2 sat between them is speculation. The sources say only that it "presumably sat somewhere in that family."
The service documentation is where the LK2's history gets useful. Linn's manual for the series notes that the LK2 circuitry is "notoriously difficult to fault-find on in the traditional way," meaning tracing signals and measuring voltages. The per-channel trip circuit makes diagnosis harder still, because a tripped board receives no power at all. The manual's workaround is to fault-find with the power off, working from symptom tables. It also records that roughly 60-70% of faults in the LK260 and LK275 boards trace to just four components. Linn issued a "Reliability Modifications" procedure, coupling the LK2(60) with the LK275, that owners were advised to apply preventively even to working boards.
Linn's own position on supporting the LK2 is stated plainly in the manual. The amplifier has been discontinued for a considerable time, spare parts cannot be guaranteed, and many are simply no longer available. Linn commits to supporting a product until five years after final build, and says it will go further and repair anything it can, but not where the parts have run out. A fault that needs an obsolete part may be terminal.
eBay Listings
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Collectibility & Market
The LK2 trades as a package component more often than as a standalone. Recent undated listings include a Linn LK1 preamplifier paired with an LK2 at $800, a standalone LK2 described as a solid-state stereo power amplifier at $1,199, and another LK2 listed as "Pure Dual-Mono" at $872. A fourth listing at $899 bundles an LK1, LK280 and Dirak power supply and does not name an LK2 at all — it surfaces in LK2 searches but isn't one. HifiShark aggregates LK2 listings without stating a market price, and no dated sale data appears in the record. Treat those asking prices as asking prices.
Owner testimony is warmer than the market data. A French reviewer on the Klout page at audioreview.com reports owning a restored old Linn LK2 that he likes as much as the Klout, driven by an LK1 preamp he prefers to the Kairn. A Vietnamese seller's video description characterizes the LK1/LK2 pairing's sound as gentle and warm, "like tubes" — a non-English marketing characterization to be taken with salt, but consistent with the affection these amps attract. One Audiogon seller notes their LK2 was bought new by their father and passed down, which is the sort of provenance that explains why so few come up for sale.
Buyers should go in knowing three things. First, the published power rating is conflicted — approximately 60W into 8 ohms by most accounts, with a 50W/100W alternative in circulation — so don't buy on the number. Second, the trip circuit demands patience: after a protection event, leave the amp off for the full 20 minutes or you'll be waiting another 20. Third, spare parts are gone; Linn says so directly. A tested, working unit is worth a premium over an untested one, because the repair path may not exist.
Related Models
- Linn AV 5105
- Linn Klimax Solo 500
- Linn KLOUT
- Linn LK140
- Linn LK240
- Eico 3150 (1967)
- Fisher CUSTOM-ELECTRA-I (K-14/K-15) (1957)
- Fisher CUSTOM-ELECTRA IV (E33/E44) (1960)
- Akai AM-2400 (1978)
- Akai AM-2600 (1977)