Art Dudley Listening

"Push it gently in the foam to correct." It sounds like a line from The Dairyman's Guide to BDSM, but it's actually a quote from the installation manual for Linn's latest upgrade for the Sondek LP12 turntable. The kit in question—a DC motor, plus an outboard power supply/control unit—is probably the most extreme to arrive from the Scottish firm, thus earning one of the company's least abstract name in ages: It is, indeed, the Linn Radikal. And along with a newly designed onboard phono stage called the Urika, the Radikal is the latest of what Linn calls their SE-series upgrades (footnote 1).

The idea for a DC-powered LP12 is nothing new, having been realized in commercial LP12 upgrade kits by such outside firms as Pink Triangle (1986) and Origin Live (1995); indeed, the founder of Linn, Ivor Tiefenbrun, is said to have expressed interest in the concept some years ago. But according to Linn, it wasn't until fairly recently, while developing an anti-jitter clock for their Klimax DS digital player, that the company discovered a DC speed-control technology that met their requirements.

The resulting upgrade kit is built around a very serious-looking motor housed in a custom-machined shell of acetal (polyoxymethylene) and aluminum, this housing itself damped with an inner layer of polyurethane sealant. From the outside, the new motor looks nothing like its predecessor—the latter being an off-the-shelf Dutch motor, at times modified by Linn with an external thrust bearing—while on the inside it boasts neodymium magnets, precious-metal brushes, and a rotor design that's said to virtually eliminate electromagnetic interference (bad) and magnetic cogging (very bad).

The top surface of the new motor housing has a pair of threaded mounting holes that line up perfectly with those for the original mounting screws—blessedly, the setup technician no longer has to contend with separate mounting nuts. A foam ring on the housing's top surface, just under the drive pulley, serves as an equally blessed substitute for the hated metal domes that had been used to isolate LP12 motors ever since the Linn Nirvana upgrade kit of the 1970s.

In addition to ditching the domes, the Radikal also dispenses with the two adjustment screws that were used to tilt the motor one way or the other (by flexing its thin-metal mounting flanges—a kludge whose sell-by date was overlong in coming) for mechanical rather than electrical fine-tuning of the platter's running speed. The threaded holes vacated by those sacked screws are now put to a loftier use: bolting in place the Radikal's optical tachometer, a claw-shaped thing that appears well engineered in its own right. The LP12's plastic belt guide also gets the heave-ho, partly because it isn't needed, and partly so that one of its screw holes can act as a wiring conduit between motor and tach.

The humblest and the most exotic parts of the Radikal kit work tightly together: A small strip of black felt, which the installer adheres to the inside of the platter rim, reports the speed to the outboard control unit, which in turn regulates the voltage to maintain consistently steady and accurate speed. (According to Linn, the Radikal system recalibrates itself every time the motor is switched on.) Linn says that the Radikal speed-control system will even compensate, over time, for the natural wearing-in of the motor's brushes. And in a manner not unlike that of its predecessor, the Lingo power supply, the Radikal allows the user to change the LP12's speed from 33.3 to 45rpm, and back again, without needing to stop the deck. For that matter, Linn says that the Radikalized LP12 can be switched off to change LP sides—or for any other reason—with no sonic penalty. (Most Linn enthusiasts agree that an AC-powered LP12 sounds its best after it's been running for a while.)

In addition to the Radikal's speed-control circuitry—which takes up surprisingly little room—the outboard box also contains the latest generation of Linn's switch-mode power supply, the basic components of which are kept to one side in a shielded subenclosure of their own. The supply also powers the above-mentioned Urika phono stage, in case you want one of those, too; Linn says that the regulation and filtering circuitry for the Radikal and Urika are isolated from one another in more ways than one, to prevent sound degradation.

Countries with a poor earth
At the end of 2010, Linn's North American distributor loaned me a Radikal kit to install in my own LP12. The neatly packed carton contained the Radikal power supply—a nice-looking if unremarkable gray box, identical in size and shape to many of Linn's other current products—plus the DC motor, the onboard tachometer, a new on/off switch, a new drive belt, and the self-adhesive black felt strip for the inside of the platter. The installer must supply his or her own Linn setup jig; a No.10 Torx screwdriver; a No.2 PoziDriv screwdriver (a small, very good-quality Phillips screwdriver will suffice); a very small flat-blade screwdriver; and a small adjustable wrench.

Perhaps needless to say, the installer will very likely not be you: Now as always, Linn products are sold only by trained dealers whose job it is to supply more than just a sealed carton and an encouraging pat on the back. But Linn's distributor agreed to let me install the loaner myself, so that I might give you an idea of what's involved. To that end, they also supplied me with the .pdf file of the Radikal's exceedingly clear installation manual.

Tools at the ready, and having dispensed with the obvious first steps—removing the outer platter, securing the tonearm and cartridge, and locking the LP12 chassis into my well-worn setup jig—I began by removing my Linn's fiberboard bottom cover, after which I unscrewed and removed the plastic clamps that hold the AC cable in place. After disconnecting the electrical leads from the motor and the on/off switch, I used a pair of needle-nose pliers to compress the nylon pegs holding the onboard PCB—in my case a Basik board, although the procedure would be the same for a Valhalla board—to the LP12's metal crossmember. Then I removed the motor, the belt guide, and the old on/off switch. Given that the latter is something I do no more than once every five years, it took a bit of fiddling before I remembered to locate and then compress, with a flat screwdriver blade, the plastic tangs on the side of the switch housing: Out it popped, like a bad tooth.

Installing the new motor was a breeze—the experienced Linn mechanic will be grateful for not having to hang two metal domes, a motor flange, and a tiny nut all on one inverted screw—and I had no trouble routing and clamping in place its gray umbilical cord. A smaller and much shorter cable from the motor, terminated with a 3.5mm plug, was plugged into the new on/off switch—itself easy to snap in place—and a remaining pair of thin electrical leads was coaxed above the board through one of the belt-guide holes.

The tachometer board fit neatly and easily in place, after which I fastened to its miniature screw terminals the twin leads from the DC motor. (The Radikal kit does not require soldering: a boon to those of us for whom the appeal of inhaling carcinogens has begun to pale.) Then I applied the black felt strip to the inner edge of the outer platter, eased the platter into place, and connected the umbilical cord to the Radikal's outboard power supply. Slightly less than an hour after it began, my task was done.

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Footnote 1: Linn Products Limited, Glasgow Road, Waterfoot, Eaglesham, Glasgow G76 0EQ, Scotland, UK. Tel: (44) 141-307-7777. Web: www.linn.co.uk. US distributor: TC Group Americas, 203 Eggert Road, Buffalo, NY 14215. Tel: (519) 745-1158. Web: www.tcg-americas.com.