From one extreme to the other: after letting me loose on their cheapest speaker, the £400 per pair Ion, Loth-X has sent over a £10,000 single-ended triode integrated amplifier. Talk about covering all price points. I'm told this isn't even their most expensive unit, so I can only wonder at how they top it; then again, we live in a world of £3,000 fountain pens and investment banker types prepared to drop £44,000 just on the wine with their meal at Gordon Ramsay's Petrus. Who am I to say that it's expensive?

Then you learn that it puts out a mighty 8W/ch. Yes, a nominal eight watts, with no missing zeroes. According the importer, it's probably 15W, but who's counting? At this level, you're still limited to speakers of the highest sensitivity you can muster. Suddenly there are horrific flashbacks to the height of Ongaku madness, amps swapped for Mercedes SLKs, yadayadayada. But it took me all of six seconds to fall in love with this amp, even though I won't let a horn speaker within 50 yards of my listening room and its heart is a pair of 300Bs - hardly my favourite tube despite my love affair with Air Tight's application of said glassware. In this case, as with Air Tight, we're talking about a pair of the new Western Electric 300Bs, the ones which come packed separately in their own wooden coffin and account for at least 10 percent of the ten grand outlay.

They nestle on a bed of solid aluminium, flanking a pair of 5965s and a pair of 5687s. And I do mean "solid": the JI-300's chassis is precision-machined out of aluminium stock, hand-finished to a standard associated with medical equipment, and the whole unit weighs a hefty 49lb. Until you see this in person, you can't really appreciate just how luxurious it is, how it oozes opulence, a sybaritic toy with such presence that you can't take your eyes off it. And it isn't size-related: at 15.5x13.5x9in (WDH), it's hardly on a par with a Theta Dreadnaught. No, it's all down to finish and clean lines and attention to detail. Even the two control knobs, for source select and level, are milled out of solid aluminium and filled with ball bearings. If you're one of those who's dazzled by the feel of an amp's switchery, one twiddle with this and you'll be hooked.

As for the looks, simplicity is the key - truly less is more: those two knobs and a blue pilot light are all that the front panel carries, while the top plate holds only the six valves and the transformer cover is utterly devoid of trim, printed legends, logos or other distractions. The only identification of the unit's origins are the extremely subtle engravings - model name below the pilot light, brand-name to the lower right. At the back, just the requisite sockets for five line inputs, tape output, on/off rocker switch, IEC mains socket and binding posts to allow the use of 8 or 16 ohm speakers (4 ohm taps are available on request).

As is part and parcel of the single-ended triode community's approach to reality, there is an element of mystery to the circuitry of the JI-300. According to its designer, who allegedly worked on high-tech military power supplies, the circuit is unlike any other SE, especially the 'rectifier-less' power supply and the output transformers; power supply impedance is fifty times lower than conventional rectifier/filter supplies. The power supply contains 150 components and is supposed to replicate DC power via an innovative new circuit; as the importer said, "Don't ask me - we couldn't get into the amp!" The output transformers are toroidals and have foil windings as well as round section copper wire and is said to be the world's first semi-silver-foil output transformer. (The theory is that foil suffers 24 times less skin effect than wire in this application.) According to Eminent Audio, the design was so complicated that a new machine had to be built to do the work.

As you'd expect of an SET design with a price to match the new Mini, parts quality is beyond criticism, Loth-X drawing "on our extensive listening research for the Silbatone electronics to help define the component complement of the JI-300, which includes our custom wire-wound resistors, custom oil capacitors and specially-designed Silbatone silver mica units." The aforementioned, ball-bearing'd volume control is a Tokyo ko-on 40-step attenuator, the valve bases are ceramic, there are high temperature electrolytic condensers (105 degrees C), and, of course, the aforementioned, highly-desirable Western Electric 300Bs instead of the Chinese-made alternative which has more in common with another Chinese specialty: fireworks.

Given my abject hatred of horn speakers, down there with kidney stones, Radiohead, SUVs and New Labour, I used instead the Wharfedale Diamond 8.1, the Stirling LS3/5A, the Tandy LX-5 PRO and - surprise, surprise! - the Krell LAT-2. Yes, the Krell speaker weaned on amplifiers some 50 times more powerful than the JI-300. And yet it drove the LAT-2s to deliciously satisfying levels in my 12x18ft room...with witnesses. Sources included the Krell KPS25sc and KAV280cd, Musical Fidelity Nu-Vista 3D and Marantz CD12 CD players. Wiring? My now-fraying A.R.T. looks-like-it-came-off-a-clothes-iron speaker cables and Kimber Select and Discovery turquoise interconnects.

As the previous amplifier to regale me was the magnificent Krell KAV300iL integrated, which hands-down pummels the Loth-X into the ground power-wise, I was asking for trouble. Or so I thought. Instead, because I'm mature enough to pay close attention to level matching, the Loth-X represented itself merely as something different, an experience with about as much of a relationship to the Krell sound as red wine has to white. Yes, both devices amplify signals. Yes, both could be described as satisfactorily 'high end'. But that's as far as it goes.

Where the Krell offered unparalleled speed, bass control and extension, the Loth-X produced midband warmth, treble which shimmered and a palpably three-dimensional soundstage on a scale deeper than, if not quite so wide as that of the Krell, or Musical Fidelity's M3. All the while, I and other listeners were aware of a slight loss of bass and of absolute headroom relative to solid-state alternatives, but the trade was for a more liquid midband and a freedom from slight glassiness which could lead to fatigue. As one colleague remarked, 'I could listen to the Loth-X for 10 hours straight.'

It only took a couple of key recordings to pinpoint the true raison d'etre of the Loth-X, with unplugged and/or vocal performances exploiting the JI-300's incomparable delicacy in a manner which seemed lost on other amplifiers. Remember, this is all by matter of comparison, relative but probably irrelevant in that - had I never heard the Loth-X - I would not know that other amps were unable to ape precisely its extreme finesse. Believe me: you'd have to be one exceptionally hard-to-please listener to find fault with the Krell, the Nu-Vista or other amps of their calibre. But the JI-300 - it's the most feathery, graceful-sounding unit this side of the Air Tight ATM-300. And it adores the LS3/5A.

With discs from the Persuasions, the Judds and the Corrs to test its way with harmonies, with some Eric Bibb and Keb' Mo' for both vocal textures and unamplified guitars, the JI-300 produced sounds which can only be described as 'natural', with rich harmonics and - best of all - realistic space around the performers. It didn't quite match the Krell in this area: there's something to be said for the absolute silences (when appropriate) of top-flight solid-state amplification. But the haze was minimal, barely detectable and therefore tolerable; you have to strain (like a reviewer) to detect it.

While no 300B-based device will ever be able to produce all of the impact, let alone the extension, of a bass drum, the Loth-X did about as a good a job with it as any SET I've tried short of those fitted with 6C33Cs, 211s or 845s. A burst of Kodo drums through the Loth-X followed by the Krell proved mildly embarrassing, but it was to be expected. And before I'm bombarded with letters from horn lovers who declare this review invalid because I didn't use horns, let me pre-empt them: the reason I loathe horns is because of the way the suck at the frequency extremes - screechy treble and flatulent, nay, comical bass. Quite simply, I was hearing the limitations of the 300B, regardless of the speaker type.

But that's all beside the point. You don't buy low-power tube amps if you live on a diet of Kodo Drummers and repeated playings of the Glory soundtrack. You buy an amp such as the JI-300 because you want your music intimate and you get chills from a breathy Christy Baron track or you want to hear fingers against strings or you read too many Japanese audio magazines.

Whatever the procedure leading up to your purchase of a single-ended triode amplifier - and here we're NOT talking about a guru/con-artist beating you up to buy the damned thing - there is a 'non-sonic' element which the Loth-X JI-300 has over every other SET amp I know bar the WAVACs: sheer physical presence. If someone were to dip into his or her pocket and buy it on looks alone, as a piece of sculpture, never to switch it on, I could understand the thinking. But to do so would be to miss the JI-300 in all its glory, like purchasing a Bugatti T57 and never taking it out for a drive. It's that kind of 'class', that sort of magic: an amp which is a delight to look at, to savour in its sheer physical form...but even better to use.