It’s 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. Founder Julian Vereker 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.
Whilst many regarded this as a weakness on his part, in some respects it was his strength. There was a strong orthodoxy in solid-state design, with amplifiers being regarded as (the saying went), ‘a piece of wire with gain’. The conceit was that all sounded the same providing they had been properly designed. Julian blew a hole through this, being able to demonstrate dramatic differences and account for them too. The first Naim product was the NAP 200 power amplifier, and it soon got the NAC 12 preamplifier to partner. They were both designed for his personal use only, then productionised, and this rather 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…
Julian Vereker was a firebrand and a maverick. In this, he had much in common with Linn Products’ Ivor Tiefenbrun and the two British hi-fi company MDs became great friends; they were fast living, robust talking, creative types who acquired something of a reputation for being playboys in the early days. They may well have been, but they certainly worked hard too. Julian’s gift of the gab made him very good at explaining to both potential customers and later hi-fi journalists just what set his products apart. This wasn’t mere hyperbole, because Naim amplifiers were different – arguably for better and for worse.
The NAC 12/NAP 200 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. Most British hi-fi magazines loved it, and began recommending it to the general exclusion of almost everything else. There were some brilliant Class A, V-FET and latterly MOSFET solid-state designs appearing on the scene in late nineteen seventies, but these were sometimes hard to notice because of the miles of column inches that many magazines of the day gave to the Naim. Julian explained its sound in terms of making, “a musical signal that I could compare with the sound of live music”, and this pretty much hit the nail on the head. However, it was important to caveat this with the point that Julian was a big rock fan, and didn’t spend much time listening to anything else.
His 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 very interested in power supplies however, and did his best to over-engineer them with each NAP 250 running a very 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; this wasn’t 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 from the word ‘go’.
By 1978, the NAP 250 was really causing a stir, and had become a ‘fave rave’ (as they used to say in the seventies) of many a 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 a very successful partnership 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.
In 1984, the NAP 250 was given a close cousin in the shape of the NAP 135 mono power amplifier. This was ostensibly a NAP 250 with its two stereo channels split into individual boxes and of course given their own power supplies. This was a formidable device, regardless of what configuration it was used in; most people partnered two of them with a NAC 32.5 preamplifier and Hi-Cap power supply, although the famous Linn/Naim ’Six Pack’ was made up of six NAP 135s, driving NAXOs into Linn Isobariks with each channel’s bass, mid and treble each getting its own NAP 135. The power output remained the same at just over 70W RMS, but the circuit layout was slightly different, with Naim able to pay better attention to grounding, with a star ground bus bar between the big smoothing capacitors. A cooling fan was also fitted, useful when the 135 was called upon to drive very awkward loads – which it did better than most other transistor amps of its era. Linn’s Isobarik loudspeaker was famously one of the few loads tricky enough to trip this fan on in normal use.
Both NAP 135 and 250 were 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 at the same time, the NAP 135 was discontinued. Then in 2013, the NAP 250 was updated again with 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.
There are many who think this amplifier’s sense of pace, rhythm and timing is unsurpassed. Some 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 really rather unique. It is certainly not for everyone though; for many listeners will think it abrasive or even overbearing; it’s perhaps not the sort of amplifier that you’d want to relax in front of at the end of a long day, listening to jazz standards at low levels just before bed! This harks back to Julian Vereker’s insistence that an amplifier needs to provide a strong sense of live music.
Its close cousin the 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! Partnered with a period Naim NAC32.5 preamplifier and a decent power supply, the NAP135 sings like few others at any price and simply sounds right. Well okay, it’s ‘right’ if you like loud live music of the rock variety, but can seem a little stark and dark for classic programme, whilst jazz is fun but lacks tonal colour.
Naim’s NAP 250 and 135 are ‘Marmite’ products; some love them and some just can’t stomach them. But still the world changed a little when Naim’s first statement power amplifier was launched. Later products have bettered them in many ways, but these two remain very special to this day. For this reason alone it warrants a special place in the great scheme of hi-fi things. And with its many incarnations over the years, you might say the NAP 250 is a veritable serial thriller!
Buying and running
The great thing about buying any used piece of Naim hi-fi equipment is that the Salisbury company takes its legacy products very seriously. Many others do not, and simply stop supporting them, giving you an apologetic “no, sorry” on the phone when you enquire about servicing or spares availability. So, 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!
Because of Naim’s excellent – and surprisingly affordable – aftercare service, the prices of secondhand Naim hi-fi holds up extraordinarily well. Indeed, you might say it has some of the highest residuals in the whole industry. The used price of a Naim product may be between thirty and fifty percent higher than its price rival back in the day. This means that picking up a NAP 250 isn’t cheap; you’ll 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. And for £1,000, it still represents a hell of a lot of performance for the money.