hifi Chord Electronics Etude Stereo Power Amplifier User Guide
- June 7, 2024
- hifi
Table of Contents
EQUIPMENT REVIEW
Chord Electronics Étude stereo power amplifier
by Alan Sircom
rom the get-go, Chord Electronics’ amplifiers pushed the technology envelope.
The company was making amplifiers with switch-mode power supplies when every
other audio brand had barely even heard of a switch-mode power supply. That
ability to see technologies in other fields and turn them into viable high-
performance audio devices has seen the company go from a tiny maker of power
amps for BBC studios to a world-class maker of high-end, high-performance
analog and digital audio electronics. It’s still a small, precision operation,
but in the intervening year’s Chord Electronics has gone from kitchen-table go-kart’ brand toFormula One Engineering Team,’ and the Étude power
amplifier shows precisely why that happened. If we are being honest, the world
of amplifier electronics is getting a little bit stagnant. Yes, there has been
the Class D revolution, and let’s not forget the developments made by Devialet
in producing a Class A/D hybrid power DAC, but the former is turn-of-the-
century technology and the latter has been on the market for 10 years. While
this might seem like an eye-blink to those using single-ended triode amplifier
circuits from the 1930s, there is still room for growth. But to find that next
great innovation in circuit design, Chord Electronics went looking through
developments in amplifier designs from the past to create something
outstanding for the future.
The Étude circuit is based on a paper by Dr. Malcolm J Hawksford (emeritus
professor at Essex University), and the resultant design was developed by Bob
Cordell of Bell Labs. Cordell put forward a design that had an unprecedented
0.001 percent total harmonic distortion at 20kHz. Chord Electronics looked at
Cordell’s work from the 1980s and developed an initial design that
incorporated his topology as well as John Franks’ own, which with nested feed-
forward and global feedback, allows for Chord Electronics’ custom-designed
dual silicon die MOSFET output transistors to perform uniquely well.
The Étude circuit design intelligently adjusts and compensates the individual
linearity of the output devices, in this case, two banks of four
aforementioned proprietary 250-watt lateral structure MOSFETs. This makes for
a switch-mode-driven amplifier that Reproduced from can deliver 150W into four
ohms (or 300W in bridged mono mode). In fact, the Étude sports three separate
power supply stages inside its small, light chassis: one for the auxiliary
rails and the other two feeding the high-current active power rails. The
internal architecture of the Étude allows these power supplies to be heavily
shielded to prevent their actions from influencing the signal path.
The rear panel is densely packed, with both balanced XLR and single-ended RCA
inputs and a set of multi-way WBT binding posts taking up a lot of the rear
real estate. There are also small phase switches set below one of the two
speaker terminals; although it’s unlikely you’ll throw one by accident, it’s
worth making sure these are oriented correctly when connecting the system up
to prevent stripping back the system trying to find what’s making it sound a
bit swirly’ (in my defense, it was the end of December and several glasses of Christmas cheer had been imbibed). The case itself is finished in brushed black or natural aluminum, the only power button is the one next to the IEC power inlet, and the only indicator lights are the blue LEDs on the circuit board, which are visible through the vent holes on the Étude’s front and top right-hand side. Power it up and there’s a few seconds of muting before the gentleclick’ of a
relay puts the Étude into play mode. The same happens in reverse when powered
off. As this effectively acts as a soft start and power-down, it means there
are no clicks, pops, or thumps through the speakers during these stages. The
amplifier chassis barely gets past warm’ to the touch. It’s warm enough to know that the amp is powered up, but it’s a far cry from a Class A griddle. The new amplifier manages to successfully combine elements of Chord Electronics’ classic amplifier designs with a personality all of its own, and the two blend perfectly together. The Étude has Chord Electronics’ signature precision and accuracy of tone, dynamics, and detail that set the brand’s amps apart from the outset. There is a mountain spring cleanness to the Chord Electronics sound that is all about balanced detail (not onlybalanced’ in
the mode of operation’ sense, but more integrity to the way detail is presented that fascinates the listener). However, where the Étude also excels is the speed and pace of the presentation that could sometimes be lacking in Chord Electronics’ other amps. There’s a snap’ to leading edges here. A perfect example of what this means is Ringo
Starr’s drum solo from The End’ [Abbey Road, 2009 Stereo Remaster, Universal Music Group]. Twenty seconds into the track, Ringo masterfully addresses the he wasn’t even the best drummer in the Beatles!’ quip. It still has Ringo’s
distinctly swampy, behind the beat, feel, but he positively owns the song,
despite some good solos from all. Where this pans out for the Étude is that
you can hear Ringo `occupying’ that song perfectly, as opposed to just laying
down a beat.
“The new amplifier manages to successfully combine elements of Chord Electronics’ classic amplifier designs with a personality all of its own.”
A lot of very clean, slightly sterile-sounding solid-state electronics lose
that distinction, and Ringo could be being covered by an admittedly very good
drum machine. Here, the clean and detailed sound is still uppermost, but it’s
joined by an ability to live in the music. This sounds like an abstract term,
even more so than praising an amp for its inky silences’ (the Étude gives good velvety in those stakes, too), but is understood once you hear that speed, precision, and sheer enjoyment. This is practically a perfect storm of good for a power amplifier. Most want that detail and accuracy. They want an amplifier to replicate the sound in the studio. But they also want the musicianship to make the cut too. It should sound like what went on in the studio as well as a portal to the control room. The Étude does both very well indeed, arguably better than most other Chord Electronics amps, although the Ultima is architecturally similar. There is more of a sense of musical flow to the Étude than I expected, but this comes without a trade-off (many other designs do that musical flow well, but at the expense of some dynamic range, bottom-end energy, solidity, or soundstage size), but the Étude retains Chord Electronics’ good reputation in all these aspects of performance. Ultimately, this is the first rung on a new ladder for Chord Electronics and its amplifiers. If Étude proves to be the success I expect it to be based on its performance, I would expect the technology to reach into a lot more products from the brand. The only limitations of the Étude revolve around it not being a bigger amplifier. The power is enough for most speakers expected to hang off a four-grand amplifier, but if you really go for it and partner the Étude with more demanding loudspeakers and expect it to play Wagner at Sweeping Majestically Eastward’ levels, you are going to need a bigger
amplifier. Bridging will help, but I suspect Étude will unlock a number of far
bigger amps from the brand.
A lot of column inches, web photons, and award gongs have gone to Chord
Electronics’ digital products and resident digital expert Robert Watts of
late (for entirely worthy reasons). However, with hit after hit in the digital
domain, it sometimes felt that Chord Electronics’ traditional core business of
analog amplification was being overlooked by the wider world. The Étude
redresses the balance, resets our levels, and is 100 percent down-the-line the
brainchild of Chord Electronics’ Chief Designer, owner, and Managing Director
John Franks. After praising Mojo, Hugo, DAVE, and other models in Chord
Electronics’ digital domain, it feels pretty good to `share the love’ in this.
The fact the Étude is a technological wonder that really does have something
new to say in amplification adds some piquancy.
TECHNICAL SPECIFICATIONS
Type: Solid-state stereo power amplifier
Connections: 2x XLR (balanced), 2x RCA (single-ended), pair five-way
speaker terminals
Power output: 150w into 4 Ohms (stereo), 300w (bridged mono)
Distortion: 0.001% – 0.05%
Frequency Response: 20Hz-20kHz ±0.1dB
Signal to noise ratio: 108dB
Damping factor: 10,000 Dimensions (WxHxD): 333.5x71x154mm
Weight: 3.45kg Price: £3,900
Manufactured by : Chord Electronics
Tel: +44 (0)1622 721444
URL : chordelectronics.co.uk
Finally, there’s an important aspect of the Étude that has almost nothing to do with the technology; namely, the trinity of Blu, DAVE, and Étude that I’m going to call the `Power Chord’. Unfortunately, due to the rarity of all three (they sell out faster than Chord Electronics can make them), I did not have all three Chord Electronics products to hand at the same time, but they match in terms of equal degrees of technological advancement and styling, and from memory, I’m fairly sure they match in terms of sound and performance, too. I’m hoping to put the three together later in the year to find out for sure, but I have a feeling this might be one of that ‘ stick a fork in me, I’m done!’ type systems where aside from the choice of cable and loudspeakers, the system is a complete given.
Reproduced from HI-FI+ Issue 168
www.hifiplus.com
References
- Chord Electronics - High-End Audio for Hi-Fi Enthusiasts & Professionals
- hi-fi+ - High-performance Audio and Music Reviews
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