The FiiO K9 Pro ESS was reviewed here nearly an year ago and I still think it's one of the better offerings on the market today, albeit there have been some truly excellent sources released since. In particular, the solid state amplifier space has benefited from trickle-down tech from more premium products and there have been new DACs from the likes of ESS in addition to AKM making a great comeback with its AK4499EX. There are other DAC manufacturers too and this is even before we get to the bespoke/first-party offerings which tend to be in products costing 4-5 figures. The FiiO K9 Pro ESS uses the excellent-but-expensive ES9038PRO, which has since been superseded by the ES9039PRO to a slight extent, and this DAC chipset costs more than the newer AKM AK4499EX that I personally think sounds better when implemented well. As such, there was always scope to put out a new FiiO desktop DAC/amp that uses less expensive DACs while giving you most of the feature set of the flagship K9 Pro ESS.

The FiiO K9 is basically just that and costs over 40% less at $500. This also now slots in nicely in FiiO's desktop DAC/amp line with the K3/K5 Pro ESS/K7/K7 BT/K9/K9 Pro ESS now having decent product segmentation. Clearly then the K9 must offer more than the $200 K7 does to justify this price and yet not take away enough from the K9 Pro ESS to render that redundant. This is even before we consider offerings from other brands, be it combo units or individual DACs and amps that can be stacked together. Using the ES9068AS DACs also brings in consideration from the excellent FiiO R7, although the power output is higher and overall sound from the K9 is better in my books. This uses the more expensive K9 Pro ESS as the base and takes away a few more features, including Type-C input and MQA rendering for those who care, but gives in return a cleaner looking product that is also easier to use via higher contrast text—a simple thing that results in a big improvement.

Using slightly older hardware throughout also helps bring down the cost to a more manageable level, and some of this can be excused on the likes of the K7. I would still like to see FiiO step away from the XU208 and QCC5124 to give us a newer USB bridge controller and more modern Bluetooth connectivity, but I can't fault the brand for still managing to put out a product that ultimately still did what I wanted from it. Most importantly, the power delivery stage appears to be the same as from the excellent FiiO Q7 and this is one of the best THX-based amplifiers ever in terms of producing an engaging sound that works well with high sensitivity IEMs as well as high impedance and low sensitivity headphones. I dare say that had the K9 released alongside the K9 Pro ESS, I'd have a harder time recommending the latter. As it turns out, this does just enough to merit a recommendation for itself. I am not convinced it's a $500 benchmark in itself but it does the job well enough.