audiophile, power amplifier, switch-mode, chapter audio

Look long and hard at this pre-amp and see if it reminds you of anything. Check out the beautiful matt aluminium finish, the elaborate machining and you won't have missed the glowing blue LEDs. Does the name Chord spring to mind? If it does you won't be surprised to learn that Chapter Audio is the creation of Mike Gregory who used to work for the Kent based company. I guess it was inevitable that the design of those OTT chassis would have an influence on Mike's own creations but to be fair the Chapter kit is a lot more restrained and it's only really the gratuitous use of blue LEDs that inspires the association.

For a start the new Preface pre-amp uses a linear rather than switch mode power supply, so there's no high frequency, high efficiency oscillator onboard just a 250VA full regulated supply that's designed to be as quiet as is physically possible. This despite the fact that much of the design input in the Pre-face comes from another ex Chord man Duncan Shrimpton who is spending most of his working hours in the real world of industrial electronics but devoting his spare time to projects like this.

And quite a project it is too. This is a no holds barred design, all the stops have been pulled out and what you end up with is the very best that these guys can come up with. Fortunately they seem to know what they're doing as the result is pretty damn stunning.

Some insight into what went into the Preface can be gleaned from the extensive manual that details the key components used and some of the lengths stretched to. Parts selection has received genuine care and attention, with Burr Brown and Linear Technology op-amps, ultra low ESR Panasonic Gold electrolytic capacitors and Linear Technology regulators. The mains transformers, of which there are two, are custom made and the PCB is a full immersion gold type incorporating surface mount precision resistors.

Probably the most notable variation from the norm is the inclusion of a custom designed volume pot that operates in a distinctly unusual fashion. As it drives processor style electronics within rather than an array of resistors it is infinitely rotating and the rate that it raises or lowers volume is defined by the speed at which you turn it. Turn it slowly and volume steps are reduced to 0.1dB, but spin it with enthusiasm and you can have the sort of change rate associated with logarithmic devices. This takes a bit of getting used to, especially if you can't locate the chunky remote control. But it's rare to have this degree of finesse in a remote pot, especially one that seems so devoid of character.

The hewn from solid fascia has only one thing inscribed upon it, its name, all the relevant information for the end user is to be found on the small dot matrix display. This will let you adjust a number of parameters. The usual ones: volume, input selection and balance, and some unusual ones: balanced or single ended output, phase inversion and something called sleep mode which shuts down the display and its micro-controller after a selected amount of time (choose from time spans between five and 60 seconds). Despite the fact that the display is shielded this facility ensures that the pre-amp's electrical environment is kept as quiet as possible.

Noise suppression seems to be the key to this unit's success, the designers concentrating on keeping noise down all the way out to 700MHz. This might seem a little excessive but it allows the gain to go up nearly as high before it's gently rolled off and the result is said to be a flatter phase response. I'm not generally a specs enthusiast but the claimed 0.0006% THD (22Hz-22KHz) and lower than -115dB intermodulation figures certainly look impressive.

In use its software based logic occasionally makes itself known in ways other than the designer intended, but as with all computerised kit a quick reboot by way of the mains switch on the rear panel will sort things out. I suspect that such glitches are related to the very early nature of this particular sample. More concrete is the selection of in and outputs on the back panel, these include more balanced XLRs than usual with both the most popular named inputs available in this way alone. By which I mean that the input names CD and phono can only be accessed if your CD player or phono stage have balanced outputs. Those of us with SE outputs can pick from a number of unrelated input names like Sat, DVD and Video. An approach such as you find on other high end components where each input has a number would be easier to associate than attempting to remember that the CD player is connected to the Video input. And given the flexibility of software would it really blow the budget to incorporate input mapping whereby you can associate any input name with any pair of sockets a la Naim 552 and Lexicon MC12? Actually looking at the retail prices on those components maybe it would!

It would certainly have been educational to have had a 552 on hand to see whether it's any more transparent than this superb pre-amp. I'm prepared to forgive this sample all its minor foibles for the extra veils it removes from the essential interface between source and power amp, making both of those elements sound more impressive than usual in the process. It followed a very good passive pre into the system, a prototype borrowed from Audio Synthesis that is no stranger to dynamics or transparency but which was no match for the Preface. The latter revealing surface noise, guitar amp buzz and vivacity of performance previously only hinted at. Image depth seemed to multiply dramatically, pushing the sound back through the rear wall and into the street, momentarily alarming a passing fox as it did so.

It took a while to get a handle on the Preface's full range of capabilities, a process which involved a spin with a sample of Chapter's first creation the Chapter Two power amplifier as well as extensive listening through my usual Gamut D200. Loudspeakers included the JMLab Electra 926 from the last issue and the preferred reference in these parts, Living Voice Avatar OBX-Rs. Sources were my trusty SME Model 20A/vdH Grasshopper/Groove record player and Acoustic Precision Eikos and Sony 555ES disc spinners. Cable and support is courtesy of Townshend Audio for the most part and Living Voice in the interconnect dept.

Before I began to full appreciate the Preface's positive qualities I went through a phase of somewhat restricted enthusiasm because it kept showing up the degree of compression present in many of my records - a term used in its full sense to indicate recordings rather than slabs of long playing vinyl. I started to yearn for the Border Patrol preamp that had returned to its home, cursing transistors and their inability to open up whatever is presented to them in the way tubes can. But then something happened, probably me selecting records that were not dynamically compromised, and it became clear that transparency on this occasion related to all aspects of fidelity not merely detail resolution as initially seemed the case. Dynamic transparency is as important as any other form and even I couldn't blame the Preface for revealing the compromises inherent in commercially oriented recordings.

Something else happened shortly after I mentioned this aspect of performance to Chapter. They discovered a difference in the earthing between this production sample and their veroboard prototype which had an effect on dynamics. When this (third) sample was assessed it did indeed seem to be dynamically stronger, extracting more energy from anything played through it, so that criticism was dashed.

The degree of transparency on offer from the Preface is an order of magnitude above that normally available from high quality pre-amps. The absence of RF noise in the system allows such an incredibly low noise floor that the resulting resolution takes a while to come to terms with. This became more clear with every familiar piece of music I played, favourites old and new offered up previously unheard subtleties and occasionally sounds that must have been completely masked or muddied in some way, so novel was their appearance. One graphic example being the oddly phased rhythms on 'Marakesh' from the fabulous Peace Orchestra CD. I've played this many times since its appearance in 1999 and yet never noticed this musical element sitting to the left of the left channel, out of place yet in tune.

Presumably excellent phase linearity has something to do with it. As imaging is as strong or vague as each recording allows. Reverb both natural and synthesised creating space behind, above and either side of the speakers. It's a pity that the B&W Signature 805s left before this arrived as I suspect the pairing would be absolutely stunning in the imaging department, not to mention in many other respects as well.

Timing is a key element with any audio component and on this occasion we get back to the central issue of what is on the record. You don't get a sense of enhanced speed with the Preface but leading edges are very well defined, and with some material there's a perceptibly less hurried sound. It allows more time for you to appreciate all the notes and the artistic inclinations behind them. It's not an actual slowing of pace, upbeat music with complex rhythmic structure has the vivacity and energy that it deserves but there's less blurring of notes and a more explicit rendering of the musical whole.

Individual instruments are allowed to express their character with greater subtlety than usual, the brushed drum playing on EST's Somewhere Else Before having the sort of low level resolution that reminds one of seeing individual hair strands on film. While a more aggressive outing such as Frank Zappa's While You Were Out is presented with its attack and speed in full effect.

I played a few tracks off the Red Rose SACD sampler to assess the preamp's finer qualities and was duly impressed by the presence of acoustic guitar and the way this stretched the speaker's capabilities, revealing subtle colorations that rarely show themselves. The spoken word pieces with Mark Levinson noodling away in the background were particularly well served, voices imaging with uncanny solidity and realism. The system stripping bare the recording process, venue acoustic and the limits of the format. You get a strong impression of what's missing from the picture, which means you are imagining those elements, a process that not many audio components encourage.

A second sample of the pre-amp was produced when I mentioned the functional idiosyncrasies of the first and this not only behaved perfectly but also seemed to address the only sonic reservation I had. Which relates to the degree to which compression on the recording affects the end result. The new unit still revealed compression in all its tediousness but you didn't have to turn the wick up so far to extract energy from such recordings. Decent cuts meanwhile continued to shine, I found an old Decca LP of Jacques Loussier which sounds stunning in its realism and naturalness. It's not just the SXLs which sound great this SLK disc from the early sixties is as dynamic as you can ask and incredibly spacious.

The aforementioned third sample (apparently a moving target makes for more interesting reviewing!) further enhanced dynamic performance to the extent that few records sounded flat and restricted, suggesting that in their haste to get a sample out for review Chapter hadn't really had time to get it fully finished. But the end result is worth the grief and now I don't want to give it back.

The arrival of some substantial PMC IB2 speakers late in the day served to reveal the quality of deep bass being excavated by the Preface. It is not only low and tight but also remarkably articulate, the sound of different instruments and effects being reproduced with the sort of transparency normally found in the midrange.

The Chapter Audio Preface represents a new bench mark in high end pre-amplifiers, I'd challenge any manufacturer to show me an alternative with this degree of resolution in all aspects of performance at anywhere near the price. Don't let the pretty lights mislead you this is a killer component.

Inputs: 2 x XLR balanced
5 x RCA phono single ended
Outputs: XLR balanced & RCA phono single ended

Options: Gain adjust
Absolute phase inversion
Sleep mode display switching
Remote control
Dimensions (WxHxD): 437x100x300mm
Weight: 11kg