Chord Electronics

BerTTi Power Amplifier

£3,995 RRP

Over the past decades, Chord Electronics has honed its design to the point that its products come very highly praised for their appearance, build and finish. The company has ploughed its own furrow, so to speak, and deliberately avoided following the paths of its rivals as far as aesthetics and ergonomics are concerned. The new BerTTi power amplifier you see here very much embodies this, being superbly built both inside and out – precisely what you'd expect for the upper-tier niche sector of the market that is high-end desktop audio.

It is a central part of Chord Electronics' so-called Table Top (TT) range, joining the Hugo TT2 DAC/preamp and the M Scaler. These are midi-sized, strikingly styled high-end separates with various brightly coloured lights that imbue an almost toy-like ambience. Together, the three make a compact yet high-quality system, just the sort of thing that so-called 'premium luxury' customers crave. The Hugo M Scaler is not mission-critical but does significantly upgrade the sound of the Hugo TT2 by upscaling the digital audio to 705.6kHz, which is sixteen times that of Compact Disc's native 16/44 resolution.

Returning to the BerTTi power amplifier, this is a fully balanced Class AB MOSFET design that puts out a claimed 75W RMS per channel into 8 ohms and 110W into half that load. It sports a special dual-feed-forward error-correction topology and twin switched mode power supplies, the latter being said to have been improved over its TToby predecessor. The manufacturer has, of course, included balanced inputs as well as unbalanced RCAs, and the speaker terminals are good quality types.

The primary difference between the older TToby and the new BerTTi is that the latter has two independent feed-forward error correction pathways within the drive circuitry of each amplifier. Each one monitors the power devices at the rear of the amplifiers and directly compensates for any non-linearities. This is said to be company founder John Franks' own version of an important topology theorised many years ago by Professor Malcom J Hawksford and developed in a compact 50W design by Robert (Bob) Cordell. There's also a new 400kHz super low noise auxiliary power supply which is said to boost the aux power rails well above the main rails, allowing for greater voltage swing for more headroom on heavy dynamic transients. Chord Electronics calls this new topology ULTIMA, and the BerTTi is the latest and smallest of its power amplifiers to receive it.

Overall, the build and finish are excellent, as you'd expect. Ten or so years ago, a rather industrious German hi-fi reviewer decided to drive a tracked armoured fighting vehicle – basically, something closely resembling a tank – over a Chord hi-fi separate, as you do. Despite being squashed into the ground, it didn't break – and that rather set the tone for the robustness of the company's products. The two-piece metalwork is all UK-made, from precision machined solid aircraft-grade aluminium. There's a choice of Jett Black or Argent Silver finishes – robust as they both are, neither would profit from having a tank driven over them, I would guess.

For the purposes of this review, I connected up the BerTTi to both my Yamaha NS-1000M loudspeakers and a pair of Acoustic Energy Coriniums, and fed it by a Hugo TT2. This amplifier is extremely easy to hook up and use, the only thing of note being the front-mounted button that toggles between standby and fully on. The rear-mounted IEC power input also has the master power switch. Thanks to the four separate fans inside, this little power amplifier runs pretty cool, making it suitable for relatively small, confined spaces. Although the BerTTi is a so-called 'desktop amplifier', I used it in my main system, sometimes at quite high volume levels, with no sense of impending overheating.

THE LISTENING

This is a very capable little power amp. Moreover, one that needs no excuses made for it on account of its small size. If you've heard any of the latest generation of Chord Electronics amplifiers, its sound won't come as a complete surprise. It offers up an unerringly clean and detailed performance, allied to a grippy, sinewy way of music making. You'd never call it a romantic-sounding amplifier; it's tonally lean and crisp, with no fat on the bone, so to speak. Yet it marries up very well with the matching Chord Hugo TT2, delivering a highly even and open window on the musical world.

Tonally it's a fraction on the spry and dry side – call it ever-so-slightly 'well lit' but not aggressively bright. This makes it suitable for a wide range of loudspeakers – even my own quite stark Yamahas sounded good, but it proved even better with the super smooth Acoustic Energy floorstanders. These it seemed to 'wake up', forcing them out of their shell. Even with bright loudspeakers, the BerTTi never descends into hardness or sibilance – it's just that some flavours of speaker suit it better than others.

Cue up Primitive Painters by Felt – a magnificent slice of nineteen-eighties indie rock with edgy-sounding jangling guitars drenched in effects – and this power amplifier hits the nail on the head. It doesn't try to smooth things out but rather focuses on the mesmeric-sounding guitars and vocals; even backing vocalist Liz Fraser (she of Cocteau Twins fame) cannot make the BerTTi screech. Instead, this power amp digs deep into the dense mix to reveal large amounts of detail and keeps doing so even as the song gets more complex. The result is a sparkling, vivid and sonorous rendition of this song, yet it remains perfectly clean even at high volumes.

When you combine this amplifier's innate clarity with its tight and taut portrayal of rhythms, you have the great combination of talents that defines the sound of the BerTTi. Often, grippy and engaging amplifiers can sound tonally forward or even harsh, but not here. Its crystal clear midband makes for a very detailed rendition of the post-punk classic The Day The World Turned Day-Glo by X-Ray Spex. Despite being recorded in a small 8-track analogue studio in the mid-seventies, this track captures what a music journalist back in the day called the “effervescently discordant” sound of lead vocalist Poly Styrene. Yet it's not the tonal accuracy or insight that really impresses here; it's the way her phrasing is conveyed. This song has tremendous drive and energy, and this amplifier works skilfully to convey it. Louche and laid back it is not!

This combination of insight and grip really gets under your skin. Compared to the cheaper but more powerful Exposure 3510 power amplifier – a great value full-size product, as anyone who's heard it will agree - the BerTTi lacks sheer guts and glory. It's a more precise, tidy and ordered sound, yet it quickly and deftly points out what the Exposure is doing wrong, making it sound opaque across the midband and stodgy in the bass. The Chord power amp's sheer insight becomes hard to live without on complex music – the crashing eighties stadium rock of Simple Minds' Speed Your Love to Me can sound vague and all over the place on lesser amplifiers, yet this one is never less than composed and controlled. It's only at really high volume levels that questions may be asked about the BerTTi's abilities, should you be driving tricky loudspeakers.

If there's a criticism to be made of this power amplifier, then it's the rather unromantic delivery of its sound – it is a tad matter-of-fact and doesn't flatter to deceive in the way that the aforementioned Exposure does, or, indeed, similarly priced tube amplifiers such as Prima Luna's EVO400. This is largely a matter of taste though, and those who love the rosy, warm soul music of Alphonse Mouzon's By All Means may think it sounds less 'plush' than nature intended. This mid-seventies soul classic has a fulsome tonality, and the BerTTi doesn't fall over itself to convey this. It does, however, get a vice-like grip on the rhythms; it locks down the bass drum and recreates everything around this with metronomic precision. The result is huge fun to hear.

THE VERDICT

Chord Electronics' new BerTTi is an excellent new power amplifier. One that offers attractive yet compact and ergonomic styling allied to serious punching power and a highly musical disposition. Although it is beaten by some rivals in outright power terms, there is still a great deal to like about its styling, ease of use and, of course, sound. It's an ideal match for the company's superb, class-leading Hugo TT2 DAC, but will also shine brightly wherever it makes its home.

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