I would like to extend a warm thank you to Paul Messenger for submitting this interview he conducted with Julian for us to use on the blog and also to Alan Sircom of Hii Plus for giving us permission to reproduce it.
The main man at Naim Audio and engineer par excellence, Julian Vereker's enormous influence on British hi-fi was formally recognised by an MBE for export in 1995. Paul Messenger talks to him about the inception of the NAP250, how the company and industry has changed, and where the future might be taking us.
Julian Vereker didn't start out as an audio engineer, and while Naim Audio is the largest and most successful of his various enterprises, he didn't particularly set out to build a classic amplifier, or even a hi-fi company. Alongside Naim he's been involved in plastics mouldings, folding bicycles, and is currently putting most of his energies into getting a very advanced and rapid cruising yacht into production. Indeed, the prize money won by his radical 'breathing' and high-revving racing engine, which cleaned up a number of 850cc Mini motor racing championships in the late 1960s, bought him the time to learn and explore the world of electronics, and investigate the potentials of new electronic devices which were coming onto the market.
PM Let's start at the beginning. How did you first get into building amplifiers?
JV "I'd always been into music, and used to hear a lot of it live in the late 1960s. A friend had this truly dramatic sounding Ovation guitar, and I was really impressed by the difference between that and other guitars. About the same time I bought a tape recorder, and was amazed to find that you couldn't hear the difference between these instruments when you played back a recording.
"So I bought a better tape recorder and microphones, designed and built a mixing desk, and upgraded the amplifier and speakers. The key bit came when I got the 'better amplifier'. The Quad 303, which the advert called 'the closest approach to the original sound', had just come out. 'Great', I thought, as I took it home, only to discover that it sounded staggeringly worse than what I was already using. At the time that was a Sinclair kit amp, for which I'd built a large power supply. I'd got hold of a very substantial transformer, spent some time thinking about the capacitors, found some mammoth car alternator diodes, and put them all into a large box. The Sinclair modules went pop quite often, but it still sounded much better than the Quad.
" 'That's very interesting', I thought, 'so amplifiers are not all the same. And not only are they not the same, but it's unbelievably easy to screw the whole thing up. If Quad can advertise that as the 'closest approach to the original sound', there must be a little gap somewhere in there for me. . . . .'
"Around 1970 I started making professional audio equipment. The first Naim Audio product was actually a small M10.2 mixing desk, and I was involved in studio tape recorders and loudspeakers too, the latter with small built-in amplifiers. A mixer customer liked the sound of my own (NAP160) amp and ordered some, but it was probably meeting Ivor (Tiefenbrun, of Linn Products) in 1974 that introduced me to the hi-fi sector.
PM If the NAP250 design was finished in 1974, what changes have you made since then?
JV "Early on, the biggest performance improvement came after I discovered how important the mechanical mounting of the power transistors was - the earliest 250s tended to go 'soft' rather quickly, especially if they were driven hard. When we went over to the extruded casework in 1980, we redesigned the boards to what they are now, but the actual component values are still basically the same.
"In the very early years, the actual transistor types did vary, but the planar type Motorola pre-drivers and the Ferranti drivers are still the same as those we used in '74. The input pair hasn't changed either, and these have to be very closely matched, because this is where the feedback meets the signal. There are no circuit configuration changes of any sort.
"The power transistors changed too in the early years, basically because what I really wanted simply wasn't available. The early Solitrons were, quite frankly, too fragile, and things got better first with the BDY56s, and then the BDY58s. I wanted a transistor which was very fast (rather than necessarily linear), without any storage time especially at low currents, and I wanted it to turn off at low currents. A year went by and I tested loads of samples, most of which seemed to get progressively worse. Then one day some unmarked transistors turned up, and looked promising when I put them in the test jig. We put them into an amplifier and bingo, that was it! We've been using these NA001 transistors ever since, exclusively, although the next generation of power amps, like the new NAP500, adopt a rather different approach
PM How do you think the industry has changed over the past twenty five years?
JV "In one sense at least I'm not sure that all that much has really changed. I didn't get into this business because it's an industry, but because I wanted to listen to music at home, and (perhaps arrogantly) sort of assumed that the kit which made me happy would make other people happy too. I reckon that the attitudes of the Quads, KEFs and B&Ws of the 1970s were quite similar to where Naim is now. They were primarily enthusiastic about music, and about taking care of their customers, and from that point of view I don't see we're doing anything very different. The fact that so much of the rest has turned to dust is just sad.
"There is one small but significant thing that disappoints me. There's a serious problem with a lot of switched-mode power supply equipment, if it's used in any system which is mains-sensitive. Everybody seems to think that compliance with CE EMC regulations is a level playing field, but because somebody somewhere really wanted switched-mode power supplies to be a possibility (probably because they use less energy resources), the standard only prohibits feeding emissions back into the mains above 150kHz. Below 150kHz you can do what you like, so all the switched-mode supplies carefully put their great big noisy peaks under 150kHz.
"If you look at the (mains interference) outputs of any of our equipment, at the various frequencies above 150kHz where they do make noise, they're just underneath the permitted standard. Big transformers and the diode switching spikes are a real devil to control - but you need them to make the thing work. Sure you can go and put a capacitor across them and the spikes will go away, but so will the music too!
"If you happen to use a switched-mode approach, you can have ten times that level of interference at 130kHz and nobody cares. But you're putting all that noise onto the mains which can upset other things, unless you put in filters which slow the whole thing down, increase the output impedance and so on. You end up with a hi-tech solution which is a disaster, limiting overall performance because it's basically noisy.
"If the mains have got more problematic over time, at least the RF environment is hugely better than it was 25 years ago, mainly because the high power black and white TV transmitters are no longer being used. There may be many more transmitters around today, but they're always much lower power devices.
"The biggest change we've gone through has of course been the CD takeover. Vinyl components (ARO tonearns, input cards, Prefix phono stages and Armageddon power supplies) are now only around 1 per cent of our business, whereas CD accounts for roughly half the total today.
"It was very important that we got into CD when we did (in 1991), because the next year (1991-2) saw vinyl shrink from 24 per cent to around 3 per cent. However, becoming a CD player manufacturer brought its own set of headaches. We've managed to develop a pretty good working relationship with Philips as a major supplier, and have made our own contributions to the technology, but two such different size companies must be working to very different basic agendas, and problems are bound to arise.
"We don't want or need to keep changing our products, never mind the costs involved, but only last week we heard that one of the key OEM components we use is being discontinued. We have to place 'last orders' for it this month, and have so far only seen one example of the new one, and that was enough to realise that it's very, very different in use.
PM "Why do they keep changing them?"
JV "Mainly because they're looking for greater versatility, and lower prices. For us this is a complete pain, so we've ordered a huge quantity of the existing parts. By the same token Pacific Microsonics are now stopping making the HDCD chips we use. Instead you now have to license software from them and load this into a DSP chip, but that represents another potential re-design, so we've had to buy a lot of chips sets too. If we hadn't built up our resources, we wouldn't be able to make such large stock investments.
"But that's what manufacturing is all about. In a way it gets more difficult, because there are less of us around using the specialist parts. More and more will be accomplished in software, and more and more things will happen on the latest clever microprocessors. We've recently put a lot of time and resources into writing our own software, and this is used throughout the CDS II and our other CD players, covering error correction, all the servos, all the laser optimisation and so on.
PM How do you see the hi-fi scene today?
JV "I have long felt and still believe that the specialist hi-fi press adversely affects the long term stability of the industry. It sets a 'flavour of the month' type of agenda, and this strongly influences a lot of dealers, who simply take the line of least resistance. Today you'll find a lot of people saying it's all multi-room and/or A/V, but that's just not true. There are still swathes of people out there that just want to listen to and enjoy music. One current challenge is finding how to get through our particular customers: keeping them, making them feel wanted and cared for, and working to make the products they're going to want in the future. To do that, often without magazine or dealer support, we're doing focus groups, collating registration documents, using the Internet, and so on.
"Technically speaking, one of the crucial things for hi-fi in the future will be about getting digital signals from A to B, and being able to recreate them sufficiently accurately when you've done that. People have had a go at us in the past about putting the DACs in the same box as the disc mechanisms, but we do that because it's actually really, really difficult to take a digital signal from one place to another and not lose the time - not make it noisy, basically. (When people talk about jitter, it's essentially just noise on the signal.)
"Some may say 'it's really easy, just put the signal into a FIFO (first in/first out memory) and you can just clock it out', but if the FIFO is in a noisy environment, the data will come out noisy. In theory it sounds wonderful, but in practice you've still got to have a really clean environment. Some chips are quite good at doing those things; others are terrible. If there's any particular secret to Naim CD players, it's making sure that the environment in which the DAC operates is as clean as possible.
"We've looked into the various proposals for transporting digital signals, such as Firewire, but it turns out they're not appropriate to a company of Naim's size. There are too many big players involved, and it turns out that a key issue for them is figuring how little data can you move in order to recreate something that 90 per cent of the market will find acceptable - all the lossy technologies like MP3, ATRAC, Dolby Digital, DAB radio etc. It's so disappointing to see, day after day in the newspapers and on TV: 'it's digital; it's perfect, it'll copy perfectly'. Which is just complete, total twaddle.
Q What sort of role do you see A/V and multi-room playing?
PM "There's a lot of talk, but as far as we can make out, there are still as many people out there who want to buy hi-fi for playing music as ever there was. On our website forum, which typically has a hundred posts a day, there's been just one thread in the past six months or so about television, and literally hundreds about records and music, turntable tuning, and other hi-fi things. If you look at our registration cards too, people aren't talking about A/V at all.
"As far as multi-room is concerned, we simply don't yet have the technology to transport digital signals around and re-create them so that the result is effectively indistinguishable from a CDS II. I'm sure one day we'll figure it out, but you have to be able to know how to do it; it's not a chance thing.
PM You seem pretty confident of finding a solution, but how do you go about that?
JV "I'm sure some day one of us will notice somebody's attempt at something like that. It's not so much getting a sudden flash of inspiration, rather it's recognising something in someone else's huge amount of work, as a clue to your problem. If I look back to the early days again, key moments came when I noticed what someone else had done. They'd found something that worked, and it slotted into my picture of what I was trying to do.
"Back when I was trying desperately to get the NAP200/250 to work, I remember someone showing me a modular American amplifier - Spectrasonics, I think it was called. I looked at the circuit and noticed a couple of resistors and capacitors which seemed to be different from anything I'd seen in other designs. This got me thinking, and then I realised that of course the positive half of the amplifier and the negative half of the amplifier are bound to be different, but they share a common feedback loop, so you have to get the two halves accurate in terms of phase gain, or you'll never make the design stable - and there were these little phase-correcting networks doing just that. I can recall other similar instances, and it's very easy to suck in those little bits if you have a clear overall picture of what you're trying to do.
"A key maxim in any design process is that it doesn't matter how good the good bits are, it only matters how bad the bad bits are. Don't waste time or effort worrying about the bits you can do, but figure out what's going to be the serious glitch. Keeping an amplifier stable when driving loudspeakers is an absolute essential. If it isn't stable at all times, then it's broken!
PM Whatever the thought processes and influences, and whatever field he's operating in, Julian has an uncanny knack of asking the right questions rather than the obvious ones, and coming up with startlingly original engineering as a result. Designing the NAP250 amplifier took a year's work by one man and his slide rule, yet it's still going strong 25 years on. The new NAP500 has also taken a year, but with a team of seven backed up by a dozen Pentiums and oodles of software. The prospect is mouthwatering.
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