Our friends in Minneapolis didn't make life any easier when they released the Reference 1 pre-amplifier. Everything in its wake has to be compared to it, and little I've heard since - the exceptions being the REF 2, the Nagra PL-P and precious few others - is in the same ball-park. But, wait! What valve through yonder mesh cage glows?

Instead of presenting me with yet-another-five-figure-unit over which to drool, Absolute Sounds supplied the model one-above-entry-level. Better still, it's all-valve, it boasts REF 1/REF 2 niceties and it costs an attainable £2999. While the LS8, the baby in the range at £1499, is one of audio's best-kept secrets, it is Spartan by today's sofa-spud standards. Doubling the money for the LS16, just in frills alone, gets you remote control for level, mute, on/off and source select, and both balanced input and output. And let me state right here that the balanced operation so slaughters the single-ended inputs and outputs that it's worth the extra for that alone. While most of you have been jerking off with single-ended triode this and Class A that, the simplest boost of all has been staring you in the face for years: balanced operation. Get with the flow, guys.

As the 'LS' tells you, the '16 is a line stage unit; Audio Research makes the PH3 if you wish to add a same-brand phono section. As it's line-only, I tried it with the best line-level source component I had to hand: Krell's so-good-it's-scary KPS25sc. Better still, I was able to A/B balanced vs single-ended to reach the above conclusion about the two because the Krell provides both sorts of connection. Moreover, as I fed the LS16 into the delicious LAMM ML2 monoblocks and the McIntosh MC275 stereo power amp, I was again offered both single-ended and balanced operation, with the LAMM and the Mac featuring both sets of inputs. Again, no contest. If there are XLR sockets on your gear - use 'em. All remarks to follow are based on balanced operation front-to-back.

Across the faceplate, it's classic Audio Research; I reckon that, with eyes closed, you could tell it was ARC just by touch. Supplied in the company's classic natural metal finish with black handles as accents (but also available in all-black form), the LS16 looks purely professional. On the left is a volume control which looks like a rotary but isn't: as per the dearer LS25 and the REF models, it operates a microprocessor over 104 steps, the action being spring-loaded and requiring short twists in either the up or down directions. To date, I've yet to hear of any assuming that it was a conventional rotary control with a 300deg arc, who forced it and twisted it off. On the right - the fascia is absolutely symmetrical - is a source selector working in a similar fashion, and choosing between three single-ended and two balanced line inputs; one is conveniently labelled 'Phono', anticipating your purchase of the partnering phono section.

As has been ARC practice for years, there's a row of toggle switches in a recess across the lower section, all now working in bi-directional, spring-loaded fashion. The four toggles select power on/off, operate/mute, tape monitor/input and processor/input; the latter allows the LS16 to be integrated into a multi-channel system while maintaining clean two-channel status. Unlike the LS15, for which it is a direct replacement, the LS16's direct input path is now a single-ended unity-gain processor pass-through, as per the LS25 and REF 2. And the remote? This tiny hand-held device covers all the functions bar processor select.

Around the back, Audio Research has fitted the requisite inputs and outputs with rugged, top-grade connectors. The single-ended inputs and outputs feature gold-plated phono sockets, while balanced in and out occur through robust XLRs. Also new for ARC is the long-awaited fitting of detachable AC leads, welcomed by Those Who Tweak Through Cable Selection; it gave me a chance to use AudioPrism's sensational new AC cord. And you're faced with a multitude of main outputs: two balanced, one single-ended and one tape (with 0dB gain).

Inside the 19x5.25x10.5in (WHD) chassis is Class A circuitry using four 6922 twin triodes, all fitted with ARC's proprietary damping rings to eliminate unwanted resonance, vibration and microphony. Also inside are the 'latest Infinicaps' and improved power supply regulation. As regards its purist valve status, the audio circuit is all-valve, but the power supply is solid state, electronically regulated. Some will grumble, but, hey, the LS16 has been quiet and reliable, so I'm not losing any sleep over the presence of a solid-state section. Gain at the main output in unbalanced mode is 12.2dB. Input impedance for the single-ended sources is 150Kohm, and 75kohm for the balanced.

Operation is utterly straightforward, and those who have used modern ARC pre-amps will sit patiently through the flashing-green-LED phase: the 45sec warm-up/mute stage while the LS16 settles into its groove. The mute also activates automatically if anything unpleasant occurs, but I never triggered it. Warm-up is actually a lot longer than 45sec if you want to hear the unit at its best; I didn't switch it off for the entire period I had it, even though the unit had been burned in through extensive use. (I think the review sample saw action at the Hi-Fi Show.)

A curious manifestation occurred when I first installed the LS16. I had been using the Krell combo transport/DAC/pre-amp KPS25sc straight into the LAMMs, with the latter feding the Wilson WATT Puppy System 6; all wires were balanced Transparent Ultra. Note that observers were present. We inserted the LS16 into the chain, connecting it to the KP25sc's fixed outputs and thus effectively removing the pre-amp section of the KS25sc. Instead of lowering the transparency or adding grain, or whatever else audio's Gods of Minimalism have been telling us happens whenever you insert another break in or add a component to the chain...the opposite happened. It opened up, it sweetened and it grew. Yes, it , which is the only way I can describe what seemed like a figure going from foetal position to fully stretched out and standing proud. Hell, there's a Viagra gag in there just begging to burst forth, but I know what a bunch of sorry-ass prudes you lot are.

We looked at each other. We grinned. And I grinned the widest because I was playing host to a couple of pro-sector guys only recently inaugurated into the ways of the High-End Coven, two men with enough doubts about audiophilia to fill a 30GB hard drive. I mean: a couple of transistor heads for whom measurements actually matter. Instead of making things less clear, less direct, less pure, the LS16 behaved like a window. And I don't mean one of Bill Gates'.

This in itself served as proof that the need for pre-amps has not been obviated by source components with their own output controls (and, in the case of the KPS25sc, a DAC and an array of analogue and digital inputs). Like many of you, I lived through the masochistic era when passive pre-amps were all the rage, and we suffered a lack of buffered tape stages and zero gain, yadayadayada. Consider me converted: I will never bleat about 'antidotes to pre-amps' again. The LS16 transformed what was already a superb set-up.

But there's no denying that it has a sound of its own. Despite quiet operation, despite tempering the antiquity of valves with microprocessor-controlled level and source select, the LS16 is as classically 'tube' as anything this side of a Quad II. But it's minus the haze, the va-va-voom lushness or the ameliorating effects associated with tubes. What makes the difference here is that the LS16 gives you warmth without mushiness. It demonstrates, at the most dynamic extremes - Kodo drummers, Eddy Louiss synth excess - that the innate 'soft-clipping' behaviour of valves, when they're working hard, is infinitely preferable to transistors. Whatever the demands of the music, the LS16 maintains control and never berates the source or the listener through some form of sadistic misbehaviour. As such, the LS16 joins the ranks of those components that allow you to sit and listen for four- or five-hour-long stretches if that's your wont. And remember: I was using the Wilson system still adjudged by many to have an aggressive top end.

I said before that the sound 'grew' when the LS16 slipped into the chain. In retrospect, I shouldn't have been surprised, for the scale of the soundstage is this pre-amp's forte. I'm already used to a large, room-filling sound; in spite of having a room of modest dimensions, I'm no stranger to sonic vistas which give the impression that the walls have vanished. The LS16 not only provided width: it delivered some of the most cavernous stage depth I've experienced, reminiscent of the REF 1 and categorically of a performance level not attained below the price point I arbitrarily apply to what I deem are loony-tunes high-end pre-amps: £5000.

This artefact is most noticeable with purist recordings - dig out a Chesky or two - but it had an uncanny effect on mono recordings. More than one observer remarked that the early 1950s Louis Prima recordings demonstrated real depth, discernible depth, impressively stereo-like depth - make of that what you will, but I agree whole heartedly. (And why should that be any more far-fetched than people swearing blind that they can hear quasi-surround effects from a stereo pair?)

It's been a while since I used an Audio Research pre-amp. That's my loss, my fault. I'd forgotten just why this company defies fashion, surviving whatever flavour of the month comes along. The LS16, if played side-by-side with my dream anachrophile pre-amps, the SP6 and SP10, probably sounds little like those vintage classics, but I was reminded of something which was true of every ARC product I've ever used: The LS16 made listening easy. And I don't mean Andy Williams 'easy listening'. I mean that it relieved the listener of the audiophilic paranoia in which so many of you wallow, the masochistic need to suffer for your passion.

It's like that yoghurt ad on TV, where a friend says to another who's relishing a pot of the stuff, "Surely someone else, somewhere, must be suffering if you're experiencing so much pleasure?" Mazel tov: I'll stick with the Audio Research. You can suffer on my behalf.