Astell & Kern HC5 – Trusted Reviews

Introduction

Astell & Kern has nothing to prove when it comes to implementing brilliantly effective digital-to-analogue conversion hardware – its range of witheringly expensive digital audio players make that point in some style.

So bringing its expertise to bear in a much smaller, much more affordable product that’s much more focused in its functionality seems to make sense. The HC5 portable DAC/headphone amp certainly looks (and, to a lesser extent) feels the part – but does it have the performance to do justice to the brand’s reputation?

Design

• Weighs 46g
• Aluminium construction

Unlike some portable DAC/headphone amplifiers, the ones that are really only fit to be ported to and from a desktop for use with a laptop, the Astell & Kern HC5 is small and light enough to go out and about without demanding a bag or a reinforced pocket in which to travel.

Its aluminium construction is smooth and clean, and the standard of build and finish of the box is everything I’ve come to expect from Astell & Kern. At 64 x 32 x 16mm (HWD) the HC5 is intuitively palm-shaped, and the concave sides only add to the impression of handiness. 46g is not a burden, even if you decide it needs to travel in the pocket of a T-shirt.

There’s a knurled dial at the top of the HC5 (I’ve decided the end with the USB-C input slot is the top – the bottom is where the 3.5mm and 4.4mm headphone outputs are), and a single control button taking care of everything except volume control along one side.

Neither feels super-substantial in operation, and in use the sensation is not exactly that of a premium product. The screen that occupies a good portion of the front of the HC5 is bright and crisp, though, and despite containing a fair amount of information at times it’s never less than legible. 

Features

• AK4191EQ digital processor, AK4499EX DAC
• 32-bit/768kHz, DSD512
• Astell & Kern digital audio remaster upscaling

Astell & Kern is not shy when it comes to explaining the AKM’s flagship AK4191EQ digital processor and AK4499EX digital-to-analogue converter combination has never appeared in a product this small or affordable before.

Splitting the all-important decoding into two stages, says AKM, maintains greater signal integrity during the journey from digital to analogue. There’s certainly no arguing with support for 32-bit/768kHz and DSD512…

By way of an encore, Astell & Kern has also deployed its proprietary DAR (digital audio remaster) upsampling technology – switch it on (it functions with both PCM and DSD files) and the sampling rate increases more than somewhat. Then there are the six user-selectable filters (low dispersion, sharp roll-off, slow roll-off and so on) that help (in a very minor way) trim the sound of the HC5 to your taste. This is all the input the end-user gets, though – unlike some rival devices, there’s no EQ adjustment available here.

The HC5 features a variant on the ‘high driving mode’ technology Astell & Kern has deployed in some of its priciest DAPs. Horizontal op-amps help reduce the physical size of the device – but it also allows for uncommon driving power. It’s worth bearing in mind the HC5 is powered by your source device, though, so the amount of amplification power it can muster is something of a double-edged sword. 

There are 150 steps of volume adjustment available, which I can’t help thinking seems like overkill. Of course it’s nice to be able to trim the volume carefully, but for the first 20-odd stages the HC5 is basically inaudible. It feels a little like an item of specification that’s flashy pretty much for the sake of it.

Performance

• Open, detailed and energetic sound
• Great facility with organisation and soundstaging
• Not much meat on the low-frequency bones

No one should be surprised that a dedicated off-board DAC does a better job than the DAC chipset in an overworked smartphone or laptop – after all, there are plenty of products costing a fraction of the £399 Astell & Kern wants for the HC5 that prove the point.

But what is remarkable about the HC5 is, if used in conjunction with some equally capable headphones, just how significant and obvious the sound-quality improvements are.

The contrast between a Tidal-derived 24-bit/192kHz FLAC file of Ball and Biscuit by The White Stripes when played out of the 3.5mm headphone socket of an Apple MacBook Pro and when heard via the HC5 plugged into one of the laptop’s USB-C socket is night-and-day, black-and-white, hot-and-cold – choose your metaphor.

The Astell & Kern brings order to bear – the soundstage snaps into focus, and as well as being far more confidently laid out it’s also bigger in every direction. The spaces between the competing elements are made more apparent and are better defined.

There’s greater dynamism, too, and in every respect. The difference between verse, chorus and guitar solo in this recording, both in terms of volume and intensity, are far more apparent when explained by the HC5 – and the same is true with the lower-level dynamics of tonal and harmonic variation. On first acquaintance this might sound like a fairly ramshackle recording – but, in fact, it’s quite painstaking and deliberate, and the amount of fine detail the Astell & Kern can reveal and contextualise makes this apparent.

Nowhere does the uptick in detail levels make itself more obvious than in the midrange. The HC5 is a deft and eloquent communicator, able to bring a sensation of character and attitude to a voice along with the more obvious stuff regarding timbre and texture. The overall frequency response is quite balanced and even, but the midrange gets just a little nudge forwards in the interests of intelligibility – and the result is a direct and positive account of voices.

Tonality is equally consistent, with the HC5 maintaining a quite carefully neutral attitude from the top of the frequency range to the bottom. There’s no additional colour to the bright, substantial top end any more than there is in the midrange, and the bottom end is rapid and well-controlled – the attention paid to the attack and decay of bass sounds is such that rhythmic expression is confident and coherent.

There’s not a whole lot of substance to the low frequencies the HC5 describes, though. There’s a reasonable amount of punch, and undeniable momentum – but when it comes to body and heft, the Astell & Kern is more whippet than labrador. Which means there’s manoeuvrability and agility at the bottom, but not a huge amount of the out-and-out wallop some listeners are undoubtedly primed to expect. 

But where energy and unity are concerned, the HC5 is back on much surer ground. There’s a well-supervised liveliness to the way it presents music, a sensation of togetherness and performance that ultimately goes a long way to illustrating how much more capable than a sub-£100 USB DAC this Astell & Kern is. Which, by extension, explains just how much better it is than the unassisted sound of your laptop or smartphone.

Should you buy it?

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