At MMORPG, we first discovered Fiio with its line of affordable, pocketable headphone amplifiers. It's only fitting then, that we find ourselves in this edition of Golden Ears coming full circle and looking at its flagship DAC/Amp hybrid, the Fiio K9 Pro ESS. It's an utterly premium desktop unit, capable of taking over all of the audio duties for just about any device you'd keep on a desktop. It's powerful, beautiful, sounds great, and even supports Bluetooth wireless. Most importantly, it takes your listening experience to the next level by pushing your headphones to their full, unmitigated potential.
At $849.99, it's clearly Golden Ears territory, but somehow, Fiio manages to make this a good value against the competition and feel worthy of that price tag. We previously reviewed the $199 Fiio K7, one step down in the K-series line-up. What exactly does that extra investment get you and is it worth it? Find out in this edition of Golden Ears.
Specifications
Current Price: $849.99 (Amazon)
Welcome back to Golden Ears, our semi-regular review column where we explore the world of high-end audio and discover exactly what awaits you at the other end of the Buy Now button.
This column is dedicated to sound quality and the technology that maximizes it. Over our years of covering tech, the world of audio is one that seems to scale ever upward. Does that extra investment net you actual, discernible improvements in sound quality and features? What exactly do those extra hundreds get you in real world terms? That’s what we’re out to reveal.
Fiio K9 Pro ESS - What Is It?
The Fiio K9 Pro ESS is a combined digital-to-analog converter (DAC) and headphone amplifier that’s designed to live on your desktop. Thinking of it like a self-enclosed sound system. Plugged into your computer, it can take over all of the audio processing duties, ensuring next-level sound quality compared to your PC. It’s also highly versatile, supporting MQA, DSD, and Standard PCM audio. It can power headphones or full speakers. It can accept audio from USB, Bluetooth, Coaxial, Optical, or AUX line-in. It can send that audio in balanced or single-ended format.
Put another way, if there’s something you would hope for it to do short of transforming into a tube amp, the K9 Pro ESS can probably do it. It’s a high-caliber audio solution, completely removing audio processing from your computer or smartphone, and instead delivering your music and games with dedicated, high-end audio circuitry. The result is dynamic, detailed, audio that hides nothing. You’ll be able to hear your music without any veil — and if you’re upgrading to it from an integrated audio solution, you’re likely to be wowed by just how much clearer it is.
The K9 Pro accomplishes its elevated sound through careful engineering using only the best parts. It uses a dual-channel, completely balanced architecture, built upon ESS ES9038PRO DAC chips. These exist high in ESS’s product stack, offering support for high-resolution audio up to 32-bit/384kHz and DSD256. It also supports MQA decoding up to 8x so you can enjoy Tidal’s highest quality Master tracks. The implementation here is peculiar, as the actual chips can support even higher resolution, though you would need to be a savant to notice a difference. Still, there’s a lower ceiling, even if you won’t actually notice it in use.
Headphone amplification is handled by the popular THX AAA-788+ amplifiers. These amps are well known and loved within the audio community for their ultra-quiet sound signature and neutral sound profile. The amplification doesn’t color the sound at all — which can be a plus or minus depending on your tastes. If you’re used to a tube amp with its analog warmth, the 788+ is likely to sound a mite cold, but if you’re interested in hearing exactly your headphones with a surplus of power and virtually no audible noise whatsoever — a quality which increases the clarity of what you’re hearing in an immediately noticeable way.
Those amplifiers are able to put out quite a bit of power, too. The K9 Pro supports both balanced and single-ended connections. From the front panel there are 6.35mm single-ended, 4.4mm and XLR balanced ports for connecting a wide range of headphones. Around the back are RCA jacks and dual XLR jacks for connecting balanced speakers. From its single-ended connections, it’s able to output up to 2.1 watts into 32 ohms (281mW into 300 ohms). The output is identical from its balanced outputs… until you get to 300 ohms of resistance where the balanced connection is able to push nearly four times as much power, topping out at 1.1 watts.
That much power is far too much for many headphones and especially IEMs, but the control panel allows you to select your power output from low, medium, and high. Even then, you might be rightfully concerned about sensitive IEMs, but Fiio handles the staging very well and it’s able to deliver a silent listening experience. Managing volume is easy and pleasant thanks to an excellent, gold-rimmed volume wheel on the front. Once you have your gain stage set, the volume knob offers smooth operation and instantaneous response (one of my critiques of the K7 was its slight volume delay).
The volume knob adds a nice bit of visual flair that hints at the premium nature of the DAC. The design is understated, minimalist but very well built and durable. The enclosure is a simple, matte black but made of robust metal. At roughly 8 x 3 x 8 inches and 6.1 pounds, it's a substantial piece of gear but isn’t large enough to prevent you from hiding it under a monitor. It also comes with a vertical stand to save on desk space and also allow it to double as a headphone stand.
The front panel also gives you options for easily controlling the unit. In addition to the gain switch, there’s another three-way selector to set your output (DAC, preamp, or headphones). There’s also an input button to select your source between USB, Optical, Coax, Line-in, and Bluetooth. Around the back, alongside the outputs I mentioned previously are the corresponding inputs, as well as a 4.4mm line in and a jack to attach an included Bluetooth antenna. Around the right side of the device is an additional USB Type-C port to connect a phone or computer.
Bluetooth connectivity is an interesting choice and a welcome one for this listener. As the true wireless industry proves on a daily basis, convenience trumps all. There are times when streaming from your phone is just plain easier, and in those moments Bluetooth comes in clutch. As you might expect, the K9 Pro ESS supports all of the major high-res codecs, including aptX, aptX Adaptive, aptX Low Latency, and LDAC. None of these will reach the level of quality of a wired connection, but they offer the best in current wireless connectivity that’s common on mainstream smart devices.
And, of course, you can count on it to have top-tier audio components. In the graphic below, you can see a callout of some of the major features. Isolated, linear power. Dual mode clocks. Premium USB controllers and Bluetooth chips. Genuine Japanese Nichicon capacitors. Every piece chosen and engineered with sound quality as the end goal. It’s not something even the best PC motherboards can claim.
Taken as a whole, the K9 Pro ESS feels every bit of its premium price point. And while that $849 price tag will surely elicit sticker shock from many, it’s actually quite competitive in the category it exists in. The K9 Pro ESS is competing against other high-end hybrids and two-piece DAC/Amp stacks that can easily extend over $1000. While it’s a solution that’s really for dedicated audio enthusiasts, if you’re shopping in this category, you’ll find that it offers a surprising amount for its cost of entry.
Fiio K9 Pro ESS - Sound Quality and Performance
The Fiio K9 Pro ESS is an outstanding DAC and amplifier, and that’s true whether you’re just using it for music or for all of your listening. My use case falls into the latter. During my several weeks of testing, I primarily used it with my computer, though I did travel with it once or twice. I listened to lots of music, played multiple different games, and burned through all of Season 1 of Netflix’s The Recruit. It’s an audio upgrade, no matter what you happen to be listening to.
The K9 Pro ESS is a solid state amp and the THX-788+ amplifiers essentially allow it to disappear into the background. It’s utterly neutral. There’s no coloration. No added warmth. No distortion (pleasant or otherwise). It does its job of translating everything you’re listening to in full fidelity and then letting your headphones take over.
That design might seem odd. Across the internet, you’ll find reviews that discuss the sound qualities of DACs — and they’re not wrong — but the K9 Pro doesn’t impede. What it does is allow your headphones, the single greatest factor in the sound you’re hearing, perform at their full potential.
The silence of the amplification circuit does wonders for clarity and dynamic range. Coming from my PC, I was able to pick out more tiny details in my music and games, hear more realism in shows, than my gaming PC with its boldly proclaimed premium audio system is able to provide. For music, it puts you one step closer. All of the tiny details across the frequency spectrum that your headphone is able to capture are represented here. There is a sense, coming from an integrated device, that the K9 Pro is clearer because of its silence. There’s more dynamic range.
This is perfect if you really want to hear your headphones and not the pieces in between. And, let’s be real, if you’re considering an $849 DAC, you probably have some great headphones to use it with. There’s no worry about “what’s the headphone and what’s the DAC.” There’s just the headphones with the K9 Pro ESS, at least in what you’re — I — was able to hear.
This also makes it an excellent companion for PC gaming. Those same qualities allow you to hear more of the game world in MMORPGs. It’s easier to become immersed, if that’s what you’re after. In shooters, it’s easier to pick out enemy locations based on footsteps alone. You’ll hear the cacophony of a boisterous multiplayer match, to be sure, but you’ll also be able to pick out every layer of sound to the full potential of your headphones.
And great sound is great sound, no matter what you’re listening to. Right?
The power delivery is excellent. I tested it with everything from inefficient Beyerdynamic and Sennheiser headphones to very sensitive IEMs. With the proper gain setting, all of them were very usable. My favorite pairing was with the Meze 109 Pro headphones. Those headphones, pushed to their potential, sound amazing and were a joy to use with the K9.
Final Thoughts
As with every product that makes its way across my desk for the Golden Ears column, the K9 Pro ESS is for a dedicated audience of enthusiastic audiophiles that also happen to value a good deal. And the K9 Pro ESS is a very good deal indeed. It feels just as premium as you would hope at this price, and though it has an odd limit to 32-bit/384kHz, is simply outstanding.
$849 a bit too much? Take a look at the Fiio K7, which I reviewed back in November. At $199, it offers outstanding sound quality on a budget and is an excellent introduction to Fiio’s desktop DAC/amp range.
The Fiio K9 Pro ESS, on the other hand, is as worthy a flagship as I’ve found, especially at this price. Whether you’re gaming or listening to music, if you’re looking for a top-tier experience that will push your headphones to their full potential, while also offering a bevy of value-adding features, this is a great choice well worth considering.
The product described in this article was provided by the manufacturer for evaluation purposes. Some articles may contain affiliate links and purchases made through this will result in a small commission for the site. Commissions are not directed to the author or related to compensation in any way.
