Fletcher: Well, this man really needs no introduction. Pretty much anyone who is involved with audio production seems to say his name a few times a day in relation to something. Be it consoles we would like to work on, or individual modules we would like to own, or equipment that is used as a point of reference for our industry.

I'm probably asked 10-15 times a day if “it sounds like a Neve" [the point of this 'chat' is to try to get a bit better definition of just what that means]. So here's an opportunity to have somewhat of a conversation with the first name we think of when it comes to outstanding sounding audio equipment, a man I am rather proud to call a friend... Mr. Rupert Neve.

Good evening Rupert.

Rupert Neve: Good Evening...

Fletcher: Here we go...

Chrissugar: In the early days [1073], the use of the output transformer was a technical necessity or you used it to achieve a special sound…

Rupert Neve: This question goes to the heart of my original designs. I used transformers because in those days it was the only professional way of interconnecting equipment. We used balanced lines by default, if you like.

Everything was balanced and worked between 600 ohms termination. This meant that the modules which you are familiar with today would be reconnected, recycled endlessly without the problem of ground loops and so on.... When they sell old modules if doesn't benefit me in my old age trying to build a retirement fund.

chrissugar: What do you think about the new designs with op-amps [5532] compared to the old transistor designs?

Rupert: Well, to answer these I would start by saying how long have you got? One of the qualities of the original designs is that they were all single ended. This meant that there was no crossover distortion. Every IC, or maybe I should say almost every IC, includes the push-pull output stage and of course, it has very small power capability.

Such a stage will produce small amounts, maybe some of them not so small, of crossover distortion. Which is to say that there are high order harmonics present which are not in the original music --and I'm even incorrect calling them harmonics. They are spikes, which occur at the repetition rate of the signal frequency.

And, although small in nature, it can be perceived not only by the trained ear, but even by, shall we say "Joe Public". The way he would notice it is that it produces sensation of frustration as he listens to music.

Fletcher: How does the "Transformer Like Amplifier" (did I get the name right?) behave in terms of "crossover distortion"?

Rupert: I think the first thing to say is the transformer like amplifier can be configured with discrete transistors and it would be if it were important. In my 9098 console there are, I believe, last count, some 64 busses. I use transformers on all the main signal busses but, entirely due to space and weight, I use the TLA transformer like amplifier or auxiliary (auxiliaries) which are not as demanding as the main busses.

However, I also use a technique which offsets the DC at the output of the integrated circuits and so removes that crossover distortion from the zero line and places it at a higher level, usually around 0 dBu. That makes a huge difference to the percentage of distortion.

Tom Borthwick: I have a 5106 console and on an Audio Precision test it goes from 5 Hz to over 150hz. This extended bandwith, was it a concerted effort or just the result of good design?

Rupert: Good question. Well Tom, I’m guessing what you meant was 150 kHz not Hz. The transformers and all the amplifiers in these designs were of that order. The console mentioned, if I remember correctly, was a broadcast console, one of the later ones. We were paying particular attention to bandwidth. Incidentally, that console was designed by Geoff Watts, one of my earliest collegues on my design team.

Fletcher: There has been some measure of debate about bandwidth including frequencies above 20kHz, can we hear them, do they make a difference, etc.

Rupert: OK, Fletch, pin your ears back...back in 1977, just after I had sold the company, George Martin called me to say that Air Studios had taken delivery of a Neve Console which did not seem to be giving satisfaction to Geoff Emmerick. In fact, he said that Geoff is unhappy.... engineers from the company, bear in mind that at this point I was not primarily involved, had visited the studio and reported that nothing was wrong. They said that the customer is mad and that the problem will go away if we ignore it long enough.

Well I visited the studio and after careful listening with Geoff, I agreed with him that three panels on this 48 panel console sounded slightly different. We discovered that there was a 3 dB peak at 54kHz Geoff's golden ears had perceived that there was a difference. We found that 3 transformers had been incorrectly wired and it was a matter of minutes to correct this. After which Geoff was happy. And I mean that he relaxed and there was a big smile on his face.

As you can imagine a lot of theories were put forward, but even today I couldn't tell you how an experienced listener can perceive frequencies of the normal range of hearing.

And following on from this, I was visiting Japan and was invited to the laboratories of Professor Oohashi He had discovered that when filteres were applied to an audio signal cutting off frequencies of 20 kHz, the brain started to emit electric signals which can be measured and quantified

These signals were at the frequencies and of the pattern which are associated with frustration and anger. Clearly we discussed this at some length and I also would forward the idea that any frequncies which were not part of the original music, such as quantisizing noise produced by compact discs and other digital sources, also produced similar brain waves.
Fletcher: What about frequencies below 20Hz (theoretically, the low end of the human range of hearing)... how do they affect the tone?

Rupert: OK Fletch, now we get down to the meat and potatoes... I believe it is necessary to not only maintain the frequency response, to well below 20 Hz, but to keep the phase integrity. Failure to do this produces a slight muddiness and again, it is very difficult to quantify. All of my designs are kept within a phase shift of between 2 and 5 degrees down to 10 Hz

Bink: What are the most important measurement specifications, in your opinion? What specs can be thought of as less important than the resultant 'sound'?

Rupert: This is almost impossible to answer... because it depends on the function of a particular circuit. I suppose the most significant measurement is to establish that there is virtually no crossover distortion.

We currently in the Pure Path design for harmonics measured on an Audio Precision System 2 less than 130 dB down. This also applies an extremely low noise floor I'm sorry, I meant implies.... and for example, the 9098 console was measured at unity gain has a dynamic range of about 126 dB This of course is 6 dB better than any digital system can yet deliver. These two measurements are probably the most significant. Of course, when digital comes of age, we" have circuits on the bench now which will deliver better than 140 dB of dynamic range!

Ronny: Speaking of keeping phase shift between 2 and 5 degrees. Do you have any views on linear phase EQ?

Rupert Neve: Ronny, this is a perpetual question we get asked all the time. I take it you would be referring to equalizer and filters. When you apply equalization to an audio signal you are enhancing or depleting a portion of the spectrum. And, phase shift will always accompany that correction of equalization in the analog domain This is part of nature.

You can experience it by simply cupping your hands around your mouth and your voice will immediately change frequency response due to the resonator you have now applied. If you did something similar with a musical instrument the same would hold true. The acoustic resonator which you are applying is following laws of nature that include a lot of phase shift.

It sounds sweet and natural of course, some people's voices benefit more than others!!

loudist: Please excuse me if this was already asked but... regarding phase shift, isn't this one of the reasons tubes (valves) sound better to most is that the phase shift of tubes is minimal compared to solid state amplification?