Pure Gold (March 1986)

Alvin Gold

THE LINN LK1/LK2 AMPLIFIER

Last time round. I wrote of the rift that has opened up between Linn Products and Naim Audio, the two most prominent high end companies in the UK-and of the dilemma facing traditional Linn/Naim dealers who, for the first time, must take sides between the two newly warring par ties. The life of the acolyte isn't all beer and skittles.

Since then, the Linn LK1 /LK2 amplifier has been released, and it has become even more obvious than before that the Linn and Naim amplifiers represent totally conflicting ideologies; they sound quite different.

If one is right, the other can't be. Linn suggests that their LK1/LK2 is superior to the much more costly, top-of-the-range Naim 32/HICAP/135. To their credit, they've backed up that view by demonstrating the two combinations against each other to all comers at their Glasgow factory. I heard one of those demonstrations several months before the product was released, and found myself unable to go along. But it was early days, so what the hell.

I was the first in the UK to review the amp, giving it a lukewarm reception in Hi fi Answers. Since then I have been under the Curse of the House of Linn, attracting considerable flak from the company. (That's putting it very mildly indeed-their first reply used theatrical exprs like "hatchet job.") What's happened since? Subsequent reviews have been, so far, universally lukewarm. The dealer network, predictably, is split right down the middle. Quite a number consider the Linn amp rubbish.

Others, in all earnestness, describe it as a new peak in amplifier design. "You know how Naim amplifiers always seem to sound better when you improve the way a system is set up?" one highly respected dealer explained. "With the Linn amp, it isn't just a way of getting extra performance, it's a prerequisite: the system has to be 180% right or it doesn't work at all; it's just so much garbage. But when it is right, a lot. more information comes through than with the Naim, and the sound is less colored." Another dealer I know has staff members who strongly support the Linn, others who favor the Naim-any Naim- with equal fervor and zeal.

In general, though, things appear to be going Naim's way. They claim (and I have no proof to support this) that their sales have held up in the months the Linn has been on sale, with barely a hiccup in their steady growth pattern. They admit, how ever, to problems with certain distributors in some overseas markets-they'd stocked up on Linn amps and had no money to spare for buying anything else. Of the shops I have canvassed-pro and anti alike-all admit to considerable customer resistance to the Linn, and few claim that sales have reached early expectations. "We're right on target to sell one-fifth of our allocation this year," one wryly remarked.

So what is the Linn like? By way of pre amble, I should point out that when I started reviewing I was influenced strongly and, I think, positively by Linn Products. They were my heroes. Although I take issue with some of the things they have done of late, I'm in full sympathy with the general tone of the ideas they have promoted through the years, especially such things as the importance of low-level interactions between systems and unwanted transducers, and proper setting-up of such systems. Bloody typical isn't it? We can't make anything properly anymore, so we're reduced to show ing how to plug everything together. But at least we do that better than anyone else on the planet! Remember, it was Linn who reminded us that poor systems can mess up temporal in formation: rhythms can be slugged, the very pulse of music can drag and die if certain simple set-up procedures are skimped or skipped entirely. Imagine my confusion (I put it no stronger) to discover that the Linn amplifier appeared to fail in just those areas that the company have always promoted as being the most important.

I had decided to compare the Linn with a Naim 42/110, a cheaper combination and, in any case, a particularly strong middle-ranking amplifier. The Linn, even if it was only to live up to its more temperate claims, ought to have walked all over this Naim. Well, it didn't-not to my ears, any way-and visitors (some, I'll admit, with axes to grind) saw things no differently.

The Linn didn't sound bad, and the power amp, especially, had a kind of self-effacing consistency that I felt an attractive characteristic. But it was also flawed in certain areas: its timing was suspect; rhythms dragged; and there was a pervading grey ness, a kind of electronic overlay that contradicted the initial impressiveness of the sound. Nor did the amp seem as powerful as the specifications suggested--rather, it didn't display the urgency and freedom that top-rated amplifiers usually possess on driving, dynamic material. Dynamics generally seemed squashed. I'm not referring to a laid-back quality that has been re marked on elsewhere, but to a fundamental inability to properly voice and distinguish subtle differences of intonation and phrasing. The justification given by the dealer quoted earlier seems to me to be disingenuous in the extreme. To see what was to be seen, I had the amp checked by a lab.

The results were interesting. First, the amplifier distorts. Simple harmonic distortion measurements show no problems, but that's because the distortion products are not harmonically related to the applied signal. Instead, spectrum analysis shows a delayed version of the signal appearing on the output for several cycles after the applied signal ceases, with a strong DC offset, and severe ripple voltage spikes superimposed on the waveform (typical output power for these tests was 5 watts / 8 ohms). Some of this misbehavior arises due to the use of a DC servo with a long time constant, for stability purposes.

There are other shortcomings, too, some well-catalogued, others not. In the former category, insufficient gain and poor over load margins in the preamplifier have been acknowledged by Linn, and improvements should by now have been incorporated into production. On the other hand, the DC servo appears to cause gain-riding (other wise known as compression) on musical signals, and the output transistor complement is uninspiring for an amp of this pedigree (one well-regarded, budget 25-watt amplifier has twice the number of output transistors, each with a 50% higher rating). It's not all bad news. The main design features are now well known, as are the professional construction standards: the unusual BNC and Canon connectors, and so on. The amplifier has many ingenious touches that in combination ought to make it easy to build, reliable, and serviceable (early samples have been troublesome, but solutions are apparently in hand). Above all, the unit seems unlikely to deteriorate over a long period of use. This, in essence, is the justification for the surprising deci sion to use resistive ladder networks in place of potentiometers, which I under stand are fabricated from back-to-back FET junctions, and are relatively nonlinear. Linn doesn't deny this; they merely claim that distortion can be made arbitrarily low by appropriate circuit techniques.

It strikes me that if Linn has laid down criteria by which equipment is to be judged, and if said equipment fails by those very criteria, the company really has no right to complain.

IMPROVED MAGGIES?

Let me tell you a story. For quite a while now, I have been using Magneplanar MG lbs as my standard speaker for day-to-day listening, with great satisfaction and pleasure. I was more than a little interested, therefore, when the importer called to say that the MG-1b had been replaced by the MG-Ic. Not only was it better, but I could also borrow a pair for a while. Reviewing has its compensations, after all.

The loan was duly arranged and the loud speakers arrived, were decanted from the boxes, plugged in, and run in for an accumulated total of 20 to 30 hours, experience with the old ones having demonstrated the wisdom of this precautionary measure.

You've probably guessed what this is leading up to. I was dismayed to discover what I took to be a clear step backwards by the loudspeaker I respected most in its price category. The old model had its faults: the sound tended to throw itself at the listener; the effect was definitely relentless at times; and the effective listening position was measured in microns and angstroms. In fairness, the le was an improvement in both these areas. The bass sounds fuller, and, superficially at least, the sound was sweeter and more relaxed in feel. Similarly, the stereo hot seat was not nearly as closely defined as before.

The problem is that these "improvements" were, in fact, merely side effects of some serious shortcomings; it didn't take long to find where these shortcomings lay.

The imaging problem had receded because the image focus had deteriorated sharply- there was no hot seat because there was, in effect, no image (I exaggerate only a little). The sweetness of the sound came about because the energy and precision of the old model, which at times made for uncomfortable (but always stimulating) listening, had been sapped and blurred over.

What had happened? What follows was just supposition in the first instance. The main panel with its associated drive units, crossover, and other hardware had not been altered as far as I could tell, but the mechanical design of the speakers had changed radically. The original MG-lbs stood more or less upright on a large, flat, wooden bedplate with quite a large foot print. The revised speakers dispensed with this, and simply leaned back against a pair of steel angle brackets attached to the bottom rear of the panels.

In effect, the speakers lean against springs, and were as wobbly as the description implies. In addition, the leaned-back posture of the speakers, necessary to ensure stability with the new feet, means that the path length from ear to driver varies by several inches from top to bottom, which is significant within the passband of the loud speakers. Matching cause to effect is difficult at the best of times, but things seem pretty clear-cut in this case.

This story luckily has a happy ending, a moral, and a sequel. After struggling with the Maggies for several weeks, I got in touch with Cliff Stone, who makes a range of very well built (and expensive) pedestal stands of quite sophisticated design, and extracted from him a set of prototype stands to replace the Maggie springs. "U" channel sections grip the wood side cheeks near the base, and a short and very heavily damped leg runs fore and aft, spiked at each end. In the process the speakers are raised about 3" from the floor, and the upright positioning is restored. The speakers are now supported about as stiffly as is possible, short of such desperate measures as running struts to the top of the speaker.

The difference this simple and entirely practical improvement made was electrifying-I even converted an extremely skeptical distributor, who initially responded to my complaints by enlisting a tame dealer to read me the riot act. The lack of real resolution and dynamics disappeared, as did a degree of boxiness the new speakers exhibited-at one time the least likely complaint to be leveled at the Maggies. Midrange solidity and clarity were improved out of all recognition, and image depth was to tally restored-even improved on the MG-lb.

I'm not trying to sell a product with this story. For one thing, there isn't one. The stands I used were prototypes, and may or may not make it into production. If they do, it will probably be to special order only, and the price is likely to be in the region of £120 a pair. But at least we have a happy ending.

The moral is as simple as it is unavoidable: the mechanical aspects of speaker design are as important as any other parameter, and this includes the type of drive units used, and the crossover, be it active, passive, or wind-powered. With more ambitious speakers offering greater resolution, the sound goes wrong even more dramatically if the speakers are not supported by some degree of mechanical integrity. In this case, it has made me falter in my regard for Magnepan as designers. How can they be so unfeeling for the performance of their products that they throw it away so easily? Or can they simply not hear the difference? The sequel-ah, the sequel .... I've just received a pair of Apogee Duettas. These I have to tell you about, but first I've got to get back inside and listen to something.

Till then ...

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[based on a March 1986, Stereophile review article]

Also see:

MAPLENOLL 'ATHENA' PHONO UNIT