Astell & Kern HC4 Review

Most audiophiles can agree that Astell & Kern’s DAPs are some of the best sounding on the market. But they’re expensive too, which leaves budget-conscious audiophiles longing for a sound they can’t attain. Well, luckily you can now buy Astell & Kern’s affordable HC4 DAC/amp combo, which promises to deliver a sound quality that approximates its super pricey players. What kind of performance can you expect, and what kind of enhancements does it make to your sound signature?

What’s in the Box?

• A&K HC4 DAC

• Detachable USB-C to USB-C cable

• Detachable USB-C to Lightning cable

• User Guide

• Warranty Card

Look and Build

There’s no question that the HC4 is very Astell & Kerny in its appearance, with its sharp lines, and retro-futuristic vibe. This compact DAC/amp combo features a pocket-sized frame crafted from robust aluminum, and it looks a lot more solid than most dongles I’ve tested on the maket.

On the side of the little device, you’ll find the volume leveler and a switch for activating DAR (Digital Audio Remaster). DAR, a feature that up-samples your sound source, adds a fun touch to an otherwise utilitarian design. Another small touch is the tiny LED indicator, which indicates the hi-res format you’re playing.

At the bottom of the DAC, there are outputs in 3.5mm and 4.4mm for versatile compatibility. The HC4 also comes with interchangeable cables, including USB-C and Lightning for iOS devices. 

Design

The HC4 is a notable addition to the brand’s USB DAC Cable lineup, as it features AKM's DAC, which is utilized in A&K’s ultra high-performing players. The HC4 boats enhanced noise control, a more efficient power design, and ultra-precise amp technology. But we'll see if it makes an audible difference.

The HC4 supports DSD256 and sample rates up to 32bit/384kHz. But unfortunately, you won’t be able to make optimal use of your MQA files, as there is no support for this format. 

Finally, as mentioned above, the HC4 supports DAR. In addition, it can handle gaming systems with UAC1.0 and is Roon tested for seamless integration. 

Sound Impressions

To see just how much the HC4 could improve the sound quality of a headphone/IEM, I hooked it up to my cheap but famously over-performing Koss KHP40, which already has impressively wide soundstage for the price. 

I was thrilled to find that the HC4’s most defining attribute is the insane soundstage it delivers. Yes, it makes the space wider, and not just in a modest way. The difference is abundantly perceptible. In fact, I was pretty blown away by how much more expansive the space became. The sense of depth was also enhanced, with instruments sitting further behind the head. Meanwhile, along the vertical axis, placement seemed to become more nuanced. And the overall effect is a super playful and vibrant interaction between elements and dimensions.

You’ll also hear slightly greater attack or boldness in the mids, injecting tons of energy into the delivery. You'll hear extra snare impact with added firmness, and rhythm guitars with enhanced definition and substance. Finally, even on a cheap headphone, you may notice significantly improved separation and layering. The bass frequencies also feel a little enhanced, creating a synergistic combination with the confident midrange frequencies. Still, the essence of your sound signature won’t be altered. The Koss KPH40 is pretty warm and smooth, for example, and those attributes were retained.

Summary

In a nutshell, you should find the difference pretty striking – the audio experience becomes grander, cleaner, richer, and more powerful. It takes only moments to recognize a substantial upgrade in the performance of your IEMs or headphones, a leap worth several hundred bucks, in fact. Yet, the core of your headphone’s sound signature remains intact. Add to that a sleek, edgy design and sturdy build, in addition to the DAR feature, and the HC4 becomes fantastic value for money. And overall, there's no question that the HC4 delivers a sound that closely approaches the quality of A&K's best DAPs.

You can buy the Astell & Kern HC4 at Audio 46.