High-end credibility is an elusive quality, endowed because of a variety of qualifications. The most obvious? Sadly, it's price, and there's a long list of components deemed esoteric solely because of their high tariffs. Those we can dismiss outright. Next are the ones which earn kudos because of their performance; those are the products to which you should aspire. Other reasons include rarity, oddball topology, even size, but let's focus on the quality. And why Counterpoint's Natural Progression amplifiers place the company in the high-end sector.

Until these massive monoblocks appeared, Counterpoint flirted with but did not really establish itself in the high-end. Despite some sterling efforts, Counterpoint made more of a mark in the value-for-money arena, probably a tougher and definitely a more noble path. The company, though, has grown at an alarming rate, and few audiophile companies (especially those making tube gear) can boast 60-70 employees, contracts with the US government, their own transformer factory and the kind of turnover which allows for full colour advertizing in the hideously expensive American mainstream hi-fi press. The size and success of Counterpoint in the 1990s, a far cry from the days of archetypal California craziness, has allowed Mike Elliott and crew to indulge in dreamware, hence the new flagships. But Mike is a canny, cautious fellow, so the pricing is actually borderline-sane by today's standards. £7999 for a pair of amplifiers ain't exactly cheap, but it's hardly a shock when you look at the price of, say, an Ongaku.

Study the Natural Progressions and it's easy to think of Counterpoint as a specialist company masquerading as a major Japanese manufacturer. Call it cynical or call it business-like, but the Natural Progressions have been tailored to the few markets which still have healthy high-end action. With the Americans tightening their belts, Italy and Germany in deep doo-doo and the UK remaining the least important high-end market of them all, what's left is the Pacific Rim. And Oriental audiophiles demand certain features in their amplifiers, whatever the price or performance.

View it at eye level, and the Natural Progression Monaural Power Amp is unmistakeably a Counterpoint product. Available in black of silver, the NatProg features the sectioned fascia seen on Counterpoint amps for the last decade, with enough switches to provide a sense of user involvement. What the company has done to add an Oriental flavour is to slap on thick wooden end-pieces -- a standard feature on giant amps from the Japanese majors -- while the top plate is littered with all sorts of text. No, you won't need to curl up with the lid as you would a novel from Elmore Leonard, but it does spout a whole load of technobabble best left in the owner's manual. But let's not be too sarcastic. The Japanese and Taiwanese and Koreans love their labels and legends and logos, however naive, stupid and gimmicky they may seem to Westerners, and the odds are that customers on the Western side of the Pacific will buy almost every NatProg the company can make.

But the wooden cheeks and the reading matter are the only non-performance-related concessions to Eastern tastes. Returning to the fascia, it sports a meter which can show either the power in watts or the output current in amperes, switchable between the two or completely off if the meter distracts you. Above it is a small red LED to indicate clipping (rarely seen in my experience). Another rotary selects normal meter action or peak hold reading. Lastly, there's a rotary control to choose between standby and power-on, the main power accessed via a rocker at the back. To achieve maximum tube life, the company recommends leaving the mains on at the back and entering standby mode from the front when you're not using the NatProg.

Switching on from cold, always allowing for the 70 seconds it takes for the yellow LED to turn green even when switching from standby, is a long procedure. The NatProg requires nearly an hour to achieve its optimum operating temperature. If you don't mind leaving the mains on and run it from standby, you'll reach the optimum performance level within minutes of the LED turning green.

The back contains a bit more than the basics, too, including the aforementioned main power switch, mains fuse and IEC three-pin mains input socket on the left. The middle is filled with heat sinks, while the right quarter contains an XLR-balanced input, a choice of normal and inverting RCA-type unbalanced inputs (you can use both as an alternative to the XLR for balanced operation from a preamp with inverting and non-inverting outputs), a small toggle to mute the input when making connections, a speaker fuse, and two pairs of binding posts. EIther pair can be used, or both if you're bi-wiring.

There's no way around it: you're going to have to remove the text-festooned top plate to install the three tubes, and it means loosening and possibly misplacing 22 screws. At first, I thought that this was stupid, sadistic overkill, wondering why Counterpoint hadn't merely fitted the lid into slotted sides with a couple of screws to hold it in place. I soon learned that the company had a valid reason: the deadening of the top place to eliminate mechanical resonances. It wasn't enough for the company to add strategically positioned damping pads. Each screw further silences the lid, as I found by tapping it after each screw was replaced. Even the pattern of the screw holes is important, with the removal of a single screw from any point having an equally deleterious effect.

With the lid off, you see more text designed to captive the Oriental bookworm. And you notice more luxury touches, none wasted as every owner will have to look inside at least once. The chassis is made up of 30 aluminium and copper-plated steel parts, and it's substantial; it contributes in no small way to the NatProg's 75lb weight, rigidity and bomb-proof feel. You notice four massive custom-made capacitors, finished in black and topped with the Counterpoint logo. A whacking great, Counterpoint-made 2000VA transformer isolated from the chassis on Imipolex-G grommets. German 1% metal-film resistors and TRT capacitors. You think Big Bucks.

Once you've let it all sink in, you can install the three valves, a pair of 6DJ8 triodes for the Class A input stage and a valve to regulate the pair. These are fitted to vertical circuit boards, the amplifier containing four in all: the audio board on the rear heatsink containing the 6DJ8s and output devices, the centrally located power supply board dealing with regulation, rectification and filtration, the control/meter board behind the front plate containing the warm-up and protection circuitry as well as the operating stages, and the output board containing the current and voltage sensor components. It's tidy and beautifully constructed, and you'd be forgiven for expecting a Sony ES or Technics badge on the front. And that's meant as high praise vis a vis construction and aesthetics.

But this unit comes from a red, white and blue-blooded Yankee high-end firm, so it isn't a case of sushi dressed as sirloin. Counterpoint has again used hybrid tube/solid-state technology, with some interesting twists. The twin triode gain stage, for example, finds its roots in the cathode-coupled voltage gain stage of the SA-11 line amplifier and the patented cathode drive techonology seen in the SA-2000/3000/5000 pre-amps. In the NatProg, there's a double cross-coupling of the cathodes and plates of the two valves, the first driving the second through both its cathode and anode.The cathodes are directly coupled to eliminate a loss of high frequency detail and dynamics; the new circuit 'reflects' the first triode's plate onto that of the second, to further reduce distortion.

Counterpoint has been cautious with the feedback, eschewing a totally non-feedback design because the company wanted this 150W/250 amp peak-to-peak monoblock to have a damping factor high enough (they opted for a DF of 160) to handle real-world loudspeakers. (Heh, heh, heh -- I'll bet that most of the NatProgs sold in Japan will be driving horns with 115dB/1W sensitivity...) Because the double triode stage doesn't produce much distortion, that primary section required no feedback application; the small loop is applied to the second stage only. Another benefit of an open-loop first stage is the ability to employ truly symmetrical balanced inputs.

The company also believes that you can hear DC servos used to control DC offset, especially when they're employed in a large loop. In the NatProg, the DC servo is applied only to the output stage, where DC offset errors matter. On the protection side, rail fuses protect the output devices, an output fuse protects the speakers (a bypass cap reduces any non-linearities) and the mute will trigger for 70 seconds if the amp suffers from input overdriving or an internal failure.

The output section, instead of MOSFETs or standard power bipolar junction transistors, employs Insulated Gate Bipolar Transistors, hybrid devices incorporating the high-impedance input gate of a MOSFET with the low-impedance output structure of a bipolar. Counterpoint feels that this offers the best of both technologies without the limitations: the high-current capabilities of bipolars and the simple drive requirements of MOSFETS. I should tell you that Counterpoint has issued a paper describing all of the circuit details, and it's actually longer than this review. The point they're trying to make is that the name of the amplifier isn't mere hyperbole. And the NatProg doesn't sound like any hybrid I've tried before. It sounds like a tube amplifier with solid-state drive capabilities and crunchy, my-Fender-Bassman-is-cranked-to-11 lower registers.

It's also the quirkiest, most distinctive amplifier I've used. And there's the rub.

With the exception of electronic no-nos, eg OTLs driving low impedance speakers, few Big Mutha amps are the cause of mismatches. Cellos, Krells, ARCs, Levinsons and the like rarely meet proudtcs thaty can't drive well. The NatProg, on the other hand, proved to be so fussy that I couldn't believe what I was hearing. And I hasten to add that at no point were impedance or power considerations the problems. Counterpoint does want users to avoid sub-2 ohm loads, but that limits it not at all unless you own Apogee Scintillas or Mk 1 WATTs or maybe something else so rare and/or obscure that it probably doesn't matter.

Still, the NatProg adored the toughest speaker in my arsenal, the Apogee Diva in non-DAX, bi-wire mode, while it sounded positively confused with the far easier Sonus Faber Extrema. It worked wonders with the hungry and fussy little LinÊum LFX, but sounded thin with the Wilson WATTs/Puppies combo -- again, not a tough load. Am I to understand, then, that the NatProg is the world's first masochistic amplifier? Does it only sing when used with a real bastard of a loudspeaker? When it likes a speaker, you'll hear similar levels of snap throughout the frequency range, with consistent texturing; the mismatch I heard was like going active with unsympathetic bass and mid/treble amplifiers.

The cable selection made no difference, and nothing I changed improved the coherence through the Extremas. The bass through the Puppies seemed detached from the WATTs. It was puzzling. Hell, it was irritating, because I knew what the NatProg could do through other systems.

A brief aside is in order before I continue: Inside the NatProg is a rotary control which the company calls the Voice Switch. You can swing it from the standard setting to a position called 'Current Mirror Mode'. What it's doing I don't know, but Counterpoint recommends its use in the latter position if the sound of your system is fundamentally bright. Which tells me that it's a glorified tone control, whatever the technology. tried it and didn't like it. And I couldn't help wondering if its complete removal from the circuit might improve matters with the speakers which failed to sing. But that wasn't logical because it sounded so good with the others.

So I settled on the Divas for my primary listening, and I was treated to some of the most controlled and solid lower registers I've yet heard from those vast bass ribbons. I even noticed less flapping of the middle ribbons when played at loud levels. A damping factor of 160 is mid-to-high, probably above the norm, but not the highest I've tried with the Divas. The only amplifiers in my experience which offered even greater control with the big Apogees were solid-state from start to finish.

What the NatProg added to the Diva was a tube-like top end, and readers with long memories will recall that the only tube amps I've found capable of driving the Diva are the long-out-of-production Beard P100 Mk II monoblocks which certainly couldn't produce the kind of bass available from the NatProg. Add to that delicious midband clarity and treble sweetness, particularly on female vocals and strings, and you've eliminated the major complaints about hybrids.

The LFXes married well with the Counterpoint because they like both power and a silky top end. They were also useful in revealing a key virtue of NatProg performance which was consistent from speaker to speaker, including the models which didn't mate well in other areas. And that's the sense of scale. I cite the wee LinÊums because they're more in need of steroids than bigger designs. But whatever the transducer, the NatProg recreated one of the largest, most convincing, most room-filling soundstages I've heard to date. Thundering orchestral material -- check out Sousa on HFN/RR Test Disc 2 -- fills the room, while audience sounds on well-recorded live discs acquire a new level of intimacy.

Unlike so many other high-end designs, though, the NatProg has a distinct, easy-to-recognise personality. Instead of differing from its rivals only by degrees, as they do from each other, the NatProg almost approaches sound reproduction from another viewpoint. The traits it shares with the creme de la creme are its dynamics, neutrality, well-controlled imaging capabilities and effortlessness. Its standout quality, the reason why this amp will top any wants lists and be a doddle to identify in a blind test, is the VistaVision soundstage. The mark of Cain, though, is a temper which must be accommodated by matching the Counterpoint to speakers not in terms of power or impedance but how it affects the top-to-bottom consistency. Though I didn't have any speakers of the type to try, I have a gut feeling that the NatProg may sound awe-inspiring with full-range designs, like QUAD '63s, and a Martin-Logan or two.

So the NatProg isn't for everybody. But I'll tell you this: the Japanese audio loonies hooking 'em up to vintage Lowthers will be clapping their hands with glee.

Tgnise personality. Instead of differing from its rivals only by degrees, as they do from each other, the NatProg almost approaches sound reproduction from another viewpoint. The traits it shares with the creme de la creme are its dynamics, neutrality, well-controlled imaging capabilities and effortlessness. Its standout quality, the reason why this amp will top any wants lists and be a doddle to identify in a blind