Back in April, we looked at Fiio’s flagship DAC/amp hybrid, the Fiio K9 Pro ESS. It was a phenomenal piece of kit, earning high marks for both music and gaming, and offering enough power to be the centerpiece of an entire audio system. But at $849, it was priced out of reach of many listeners.
Today, we’re looking at its sibling, the standard Fiio K9, and for $350 less, you might be surprised at just how similar these two DAC/amp hybrids are. The K9 is powerful, with clean and quiet THX-788+ amplifiers, sounds just as good, and has nearly identical connectivity. Landing between the K7 at $199 and the K9 Pro ESS at $849, the K9 is a middle-option that feels like a flagship, and is just as good for audiophile-grade tunes and gaming.
Specifications
Current Price: $499 (Amazon)
Fiio K9 - What Is It?
If you’re coming to the world of desktop audio having only used the headphone jack on your PC or smartphone, introductions are in order. The Fiio K9 is a desktop hybrid DAC and amplifier. Those two terms describe the most fundamental elements of how sound gets from your PC or audio source and into your headphones or speakers. They are often two separate devices but, as is the case here, can also be found as hybrid units that combine everything in one chassis.
Breaking those pieces apart, we have two distinct audio systems and each as important as the other. The DAC is a small chip in an enclosed audio system that processes all of the digital 1s and 0s from your source into analog impulses that can be played through your headphones. The amplifier increases the volume of what you’re hearing, providing more power for less efficient headphones, and giving you more headroom with which to increase your volume. Both of these devices come in varying levels of quality and capability. The K9 has excellent components, so you’re getting a very good DAC and amp system with it.
With that out of the way, I would highly recommend that you take a moment and peruse my review of the K9 Pro ESS, as I’ll be referencing it a lot in this article. By the end of this feature, you should be able to decide which is the better choice for you, understanding the core differences between the two models.
The first thing to know is that the K9 Pro ESS and K9 have much more in common than they do different. The K9 Pro ESS exists at the top of the stack. At $850, it’s priced for enthusiasts that are willing to spend big bucks for a great listening experience (though it’s also very competitive at its price against similar products). The K9 Pro is the step down. The overall design is the same. The user experience is very similar. The sound is almost identical. The K9 Pro ESS is for listeners who want the best, while the K9 is for those of use who want great sound but don’t mind compromising on a few features.
Visually, the two are almost exactly the same. At 7.9 x 8.8 x 2.8 inches, both cut an imposing figure but are still small enough to sit under most monitors. They’re both made of heat-dissipating metal frames and have bold, centered volume knobs on the front. To the left of the knob, there’s a 6.35mm single-ended output, a 4.4mm balanced headphone jack, and an XLR port for connecting high-end headphones. To the right are switches to set output (phones, preamp, line-out) and gain (low, medium, high) modes. There’s an input button which cycles through USB, optical, coax, line-in, and Bluetooth 5.1 audio inputs, each with their own small indicator light just above. There’s also a combination power and mute button all the way to the right.
Around the back are the physical inputs for those options, a balanced input jack, as well as RCA jacks and balanced XLR output. You’ll also find a USB Type-B port and a small Bluetooth antenna. These are all present on the K9 Pro ESS also, but the K9 lacks a USB Type-C input for easily connecting your smartphone.
Inside the frame, you have a deep combination of audio and power circuitry that’s designed entirely for sound quality. It uses two ES9068AS DAC chips (a slight step-down from the ES9038PRO DACs on the K9 Pro ESS), capable of up to 32-bit, 768kHz audio, and utilizing ESS’s HyperStream tech, which increases dynamic range and lowers distortion. This is paired with a THX 788+ AAA amplifier. These amps are high-powered and ultra-quiet, eliminating noise in your listening experience. They are quite neutral and don’t color the sound, but the black background allows you to hear more and deliver more perceived clarity in the listening experience.
These systems are tied together with a level of care to sound quality that is just not present in integrated solutions, even on top-end motherboards that boast about their audio quality. The PCB is partitioned into specific sections with proper shielding to eliminate interference and crosstalk distortion. The power supplies are also completely isolated and track through a six-stage amplification system.
The K9 also matches the K9 Pro ESS in its supporting systems. Both use an XMOS2058 USB controller. Both use QCC5124 Bluetooth chips and support high-res audio through LDAC and aptX (Adaptive, HD, LL). Both feature dual oscillators to ensure the clocks stay accurate and prevent phase distortion. Both devices also feature app support so you can dial in their sound and parameters over your smartphone.
Click to enlarge and see how the K7, K9, and K9 Pro ESS compare
The biggest differences come down to power, digital filters, MQA, USB Type-C support, and technical measurements. Of these, power and the lack of MQA support and a USB Type-C port are the most relevant. Over its single-ended output, the K9 can deliver up to 1500mW into 32 ohms and 200mW into 300 ohms. The K9 Pro ESS can output 2000mW and 780mW into those same resistances. Practically speaking, this may well make no difference whatsoever depending on the headphones you plan to use, but the K9 Pro ESS is more powerful and can support a wider range of gear. But the K9 will still deliver more than enough power for the vast majority of headphones and speakers available today.
The other differences I don’t find to be all that meaningful at all. The K9 features three digital filters instead of the seven, but these filters make a very small impact on the overall sound (it can be hard to hear any difference at all with some of them).
And the reduced measurements… I don’t doubt that the K9 Pro ESS performs better in a laboratory setting with scientific measurement tools. It’s $350 more and should perform better. But practically speaking, there’s no discernible difference in sound. The K9 has all of the quality to the human ear at a massive discount. I think that’s a reasonable trade-off.
Fiio K9 - Sound Quality and Performance
With that said, to my ear, the Fiio K9 sounds every bit as good as its more expensive sibling. I remarked then that the K9 Pro ESS was “utterly neutral” and that is “disappears into the background.” That’s exactly the case here. The K9 doesn’t color your music. Instead, it provides enough power to push your headphones or speakers to their full potential and places them at the end of a chain completely designed around sound quality.
In practical terms, that means you’ll perceive greater clarity in what you’re listening to, be that games or music. The THX-788+ amplifiers are very quiet and, paired with the dual DACs, have outstanding dynamic range. You’ll hear more in the quiet parts and be able to pick out more details in the most chaotic. Layering and separation are excellent, so long as the headphone you’re listening on is also excellent in those qualities.
In my last review, I wrote:
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.
This remains true of the K9, even at its reduced price.
It’s also just as great for gaming. The enhanced clarity and range to the listening experience makes it easier to pick out small details in what you’re hearing. Even in chaotic gunfights in Battlefield 2042, I was able to hear enemies flanking around me and the direction of gunshots. In Diablo 4, the sense of space and depth was enhanced, not necessarily because of the DAC doing anything special to the sound, but because my headphones were able to operate with enough volume headroom, range, and clarity that the great work of the game’s audio engineers could come forward in a way that was easier than ever to appreciate.
The K9, like the K9 Pro ESS before it, is excellent.
Final Thoughts
The Fiio K9 is a product that’s difficult to find fault with. At $499, it offers very similar performance to the K9 Pro ESS, which is a full $350 more. It does have some limitations, like the lack of MQA, no USB Type-C, slightly less power, and reduced measurements, but these are very small compared to what you’re actually getting. Adding the K7 to the mix, you have three tiers of power, performance, and pricing. The K9 exists right in the middle, offering substantially more than the K7, and not significantly less than the K9 Pro ESS which tops the stack. If you need more than the K7 can offer, this is an outstanding pick that’s well worth checking out for yourself.
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.
