It is a long time since Naim Audio Ltd. first started up in a Wiltshire backstreet in 1973, and from that moment on began to win friends and favour. Its founder was the sadly now deceased Julian Vereker, who once explained that he established the company to make hi-fi equipment that he himself and his friends would enjoy listening to. He was different to many of his contemporaries in the audio industry in that he wasn’t a Cambridge University engineering PhD with twenty years of electronics design experience behind him. Indeed Vereker was entirely self-taught, and once said it took him a year to learn enough about the subject to produce his own amplifier.
The first Naim product was the NAP 200 power amplifier, and it soon got the NAC 12 preamplifier to partner it. They were both designed for his personal use only, then productionised, and this set the pattern for Naim amplifiers for the following two decades or so. Those early Naims were highly distinctive in their sound, and as a result extremely controversial; indeed the company was something of a ‘Marmite’ brand for many years, so polarising was the sound of its products. It sold in small numbers; it wasn’t until 1975 when Vereker really found his feet. The NAP 250 was the product in question, and became an iconic amplifier in the space of just a couple of years as well as Naim’s top stereo power amp for a quarter of a century.
Vereker’s thesis was that a power amplifier should be able to drive loudspeakers into ‘real world’ loads – which is to say impedances that vary under dynamic conditions, rather than the static ones you see on the test bench. The way the hi-fi press waxed lyrical about the NAP 250, you would have thought its power output was a kilowatt or so, but in truth it was 125 watts into 4 ohms, and around 70W into an 8 ohm load. Indeed Naim named its power amps by the total power made into a 4 ohm load; with its stereo amplifiers, to get the ‘per channel’ rating you have to divide by two. The company was right not to obsess over measured power figures; despite being of fairly small stature in the power stakes compared to the emergent American and Japanese competition, it still went loud. Indeed, it had more life and soul than many far bigger (on paper) amps, and this tallied with Julian’s stated objectives for the design of the NAP 250.
Indeed, it was an essay in doing amplifier design differently. It ran custom output transistors biased well into Class B mode, because Vereker believed this was more efficient and able to provide power better. He wasn’t overly concerned with conventional harmonic distortion measurements either, or the power output into a static load. He was interested in power supplies however, and so each NAP 250 ran a sizeable 450VA toroidal power transformer custom made to Naim’s specification by Holden & Fisher. This had two windings and twin 22,000uf capacitors feeding two regulator boards, which provided excellent dynamic headroom so the amplifier could go loud fast – when the music signal so demanded. He also insisted on DIN plugs; not such a big deal in the early seventies when the connector was ubiquitous, but by the nineties the rest of the world had moved to RCA phono connections. Naim also used recessed ‘banana’ loudspeaker sockets which ruled out spade connectors or bare wire.
By 1978, the NAP 250 was causing a stir, and had become a favourite of many a British hi-fi reviewer. Moreover, Vereker’s friendship with Tiefenbrun led to a strategic partnership with Linn, the idea being that the Glasgow company supplied the source and loudspeakers, and the Salisbury company took care of the electronics. It was very successful and the active version of the Linn Isobarik speaker (the PMS) caused Naim to develop an active crossover, the NAXO, which would partner with no less than three NAP 250s to power a pair of active Isobariks. It was a formidable combination, and acted as a ‘force multiplier’ for both Linn Products and Naim Audio for a decade from the late nineteen seventies. When Naim began making loudspeakers and Linn commenced production of electronics around 1988 though, this partnership began to cool.
The 250 was initially made of heavy aluminium extruded cases that acted as heatsinks. Painted black with a silver front edge, this style began to be called the ‘chrome bumper’ era soon after it ended in 1989. In this year, the entire Naim range got an olive green coloured front panel with a backlit Naim logo. The change caused havoc for many Naim owners, some of whom sold their entire systems to get a perfect visual match with their new Naim kit. At the time, it seemed a good thing because the early styling was beginning to look too ‘nineteen seventies’, but many now prefer the original old school Naim look. In 2002 the NAP 250 got tweaked circuitry and then in 2013 was updated again with an aluminium chassis and sleeves and a diecast zinc fascia; it’s a different beast to the original but still shares much DNA with its 1975 antecedent.
Some think this amplifier’s sense of pace, rhythm and timing is unsurpassed. They say that – although Naim makes better all-round power amplifiers now – the NAP 250 still has that special something about it. It certainly has a sense of life and vibrancy that you just don’t hear very often; rival power amps from other manufacturers all too often sound flat, lacking in energy and/or joie de vivre. They may be more powerful and might have greater grunt, but there’s still something about the way the ‘250 does its business that is rather unique. It is certainly not for everyone though; many will think it abrasive or even overbearing; it isn’t the sort of amplifier that you’d want to relax in front of at the end of a long day, listening to mellow jazz just before bed…
Its close cousin the monoblock NAP 135 is its slightly punchier, yet fractionally quieter alter ego; it is a touch more couth and smooth yet it does everything the NAP 250 does, including the magic bits! It sounds fast, furious and emotionally committed. Its bass has a vice-like grip, its midband was dynamic and expressive, and the treble crisp and biting. The NAP135 gives an even greater sense of control over the music, and easier and more explicit dynamics. In an active system as part of a ‘six pack’, it’s magnificent – but then so it should be at the price!
Secondhand values are very strong, and part of the reason for this is that Naim Audio takes its legacy products very seriously. You can buy a used NAP 250 safe in the knowledge that you can send it back to Naim for repair, or even if you feel it might need a service. As electronics age, they do periodically need recalibration, solder joints or internal connectors need cleaning, and capacitors need replacing – so it’s great to have the manufacturer still around to do it. The used price of a Naim product may be between thirty and fifty percent higher than its price rival back in the day, so expect to pay £1,000 for a good one. The other side of this is that when you do, it will likely have been serviced and be working just as well as it did when it first came out of the factory.
Naim’s NAP 250 stereo power amplifier has become a legend in its own lifetime, a cult amplifier that still represents a lot of performance for the money. The world changed a little when Naim’s first statement power amplifier was launched back in 1975, and things wouldn’t be quite the same again. Later products from both Naim Audio and elsewhere have bettered it in very many ways, yet the 250 remains seriously special to this day.