The FiiO K5 Pro ESS review sample was kindly provided free of charge in exchange for a honest review. I didn’t receive monetary or any other kind of compensation and i don’t use affiliate links. The K5 Pro ESS price is $199 (€199) and you can buy it from FiiO.eu
FiiO K5 Pro ESS
The FiiO K5 Pro ESS is a small-sized, top-notch desktop DAC and preamplifier equipped with a headphone amplifier. Although not a recent release, the original K5 Pro, introduced in 2019, has consistently been a top seller for FiiO. Initially, the K5 Pro utilized the AK4493 DAC chip; however, due to a factory fire at AKM, FiiO had to replace it with the ES9038Q2M chip from ESS, which boasts superior technical specifications.
Technical highlights
The FiiO K5 Pro ESS is equipped with an XMOS XUF208 USB receiver that supports high-resolution audio up to 768K/32Bit PCM and Native DSD512. In addition to this, it also features coaxial and optical digital inputs that can handle up to 192kHz audio signals.
One of the standout features of the K5 Pro ESS is its USB input, which supports OTG connection. This means that you can easily connect your phone or tablet to use them as a source for your audio.
The internal circuitry of the K5 Pro ESS has been meticulously designed and optimized to deliver the best possible sound quality. It incorporates a four-level audio circuit that includes a second-order low pass filter, analogue volume adjustment, and ADC curve reconstruction using the NJW1195. Furthermore, it utilizes two OPA1642 OP-AMPS for voltage amplification and the renowned TPA6120 from Texas Instruments for headphone current drive.
To ensure stable and clean power supply, the K5 Pro ESS comes with a 15VDC external power adapter. The incoming DC power is filtered by a secondary power supply, which then independently provides power to both the amplifier stage and the rest of the circuit.
Thanks to its large operating voltage and feedforward amplifier circuit design, the K5 Pro ESS is capable of delivering a power output that is more than 60% higher than its predecessor, reaching up to 1.5W/32Ω. Additionally, it offers a substantial voltage swing of 20Vpp at 300Ω, allowing for an enhanced audio experience.
I/O and user interface
The K5 Pro ESS is a versatile device that serves multiple purposes. It functions as a DAC/Headphone amplifier, a DAC/Preamplifier, and a standalone headphone amplifier when connected to an external source through the line level input, such as a phono preamp. However, it does not support Bluetooth wireless connection and does not allow for customization of the default low pass filter.
On the left side of the front face, you will find two switches. One switch allows you to select the gain between L/M/H, while the other switch allows you to choose the input between USB, coaxial/optical, and the line input.
In the center of the front panel, there is a one-piece all-metal oversized volume knob. This knob is surrounded by a circular RGB light indicator that changes colors based on the input bit rate. When the bit rate is 48kHz and below, the indicator turns blue. For bit rates above 48kHz, it turns yellow. And when playing DSD files, the indicator turns green.
Moving to the right side, you will find the 6.35mm headphone output.
At the back of the unit, you can see the RCA analogue output and various inputs including USB, coaxial, optical, RCA line IN, and DC power.
Design, build quality and accessories
The K5 Pro ESS is a small device with dimensions of 120x130x55mm, constructed from sturdy CNC aluminium and featuring a sleek black finish achieved through sandblasting.
The device boasts exceptional build quality and finish, with a volume knob, interconnects, and switches that are not only of the highest quality but also feel robust and long-lasting.
Included in the package are a power adapter, a USB cable, a 6.35mm to 3.5mm adapter, and four adhesive rubber feet for added stability.
However, please note that an RCA interconnect is not provided.
Associated gear
The unit was typically left to play music for approximately 150 hours, following standard practice. I conducted tests on the K5 Pro ESS as a DAC/Amp and headphone amplifier using the analog input. I utilized a range of headphones and IEMs, such as the HIFIMAN Sundara, Sennheiser HD660s, Focal Clear Mg, and FiiO FD7.
Power output
The headphone amplifier possesses impressive power, enabling it to effortlessly drive the majority of headphones, with the exception of a few highly inefficient models. With its gain switch, users have the option of three positions. The first position, at 0dB, is ideal for sensitive earphones. The second position offers a gain of +12dB, while the third position provides a gain of +16dB. When set to the lowest position, the amplifier operates silently without any hiss, and the channel balance is exceptional. Therefore, the K5 Pro ESS is an outstanding choice for those using sensitive earphones.
Listening impressions
The ES9038Q2M DAC chip may not receive as much attention as its more technical and expensive counterpart, the ES9038PRO, but I must admit that whenever I have come across it, it has always impressed me with its unique qualities.
It comes as no surprise that some of the top audio manufacturers, such as Arcam and Musical Fidelity in their brand new M6x DAC, choose to use this chip in their high-end equipment that costs over $1K.
When implemented correctly, the ES9038Q2M chip achieves a remarkable balance between technical prowess and musicality. The sound signature of the K5 Pro ESS, for example, is neutral and linear, offering excellent technical performance for its category while still delivering a captivating musical experience.
The timbre of the audio is natural and consistent across the entire frequency range, with only a slight exception of some upper-mid/treble digital glare that remains subtle and unobtrusive.
The pitch accuracy is mostly spot-on, and acoustic instruments sound incredibly close to their real-life counterparts.
There is a touch of warmth and smoothness to the sound, accompanied by a non-aggressive, easy-going treble that still manages to maintain excellent extension and clarity.
The soundstage is spacious, with ample air between the notes, and the level of detail retrieval exceeds expectations. The music has a good amount of intensity and natural decay, contributing to an overall immersive listening experience.
The clarity remains exceptional throughout the entire frequency range, from the mids down to the lower end, ensuring that every aspect of the music is well-defined.
Despite the individual presence of each part of the frequency range, there is a remarkable sense of cohesiveness, and nothing feels detached or disjointed.
Instruments and voices, particularly in the mid-range, are emotionally engaging, with rich harmonic saturation and precise articulation.
The sound is rich and immersive, devoid of any dryness or thinness, with a deep and well-controlled bass that is multi-layered. The dynamics are good, although not the absolute best, resulting in a softer impact. Despite this, bass drums and intense electronic beats do not have the imposing physical presence that would be ideal, but it is not something you will miss.
Both the DAC and the headphone amplifier offer a high level of transparency and detail, without being overly punishing. While the quality of the raw material is crucial for maximizing your experience, poorly recorded songs will not cause any discomfort.
The soundstage is very good, although not extraordinary. The K5 Pro ESS does not limit the sound-staging capabilities of your headphones, but it also doesn’t enhance them significantly. The presentation is spacious, with accurate imaging and ample air around the performers to avoid congestion. However, it may lack the ultimate layering, scale, and holography found in top-tier systems.
It is worth mentioning that the K5 Pro ESS performs equally well with all genres of music. I personally found great satisfaction in listening to classical music, such as this new recording of Ravel’s orchestral pieces.
Brief comparisons
K5 Pro AKM
The disparities may not be overly noticeable, but the latest iteration of ESS demonstrates enhanced technical capabilities. The audio quality is crisper, tighter, and exhibits better control. It offers additional definition and lacks the haziness and softness found in its predecessor. The dynamics have improved, resulting in extended frequency response at both ends, while the overall presentation is more authentic and awe-inspiring. While I won’t go as far as recommending an upgrade to the ESS model, newcomers can be assured that they are purchasing a slightly superior version, which is undoubtedly advantageous.
TOPPING EX5 ($359)
To obtain the dual ES9038Q2M configuration with MQA decoding, LDAC Bluetooth connectivity, and a remote control, you will need to spend an additional $150 for the Topping EX5. While the EX5 offers a balanced XLR line output, it does not have a line level input like the K5 Pro ESS. The headphone amplifier power output remains the same for both models. It is important to note that the XLR headphone socket on the EX5 is primarily for convenience and does not provide true balance. In terms of sound quality, both units are comparable, but the EX5 has a slight advantage in terms of extra clarity, improved definition, and a slightly more expansive and immersive soundstage. Both units are priced reasonably and if you require the additional features, it is recommended to invest in the EX5 by paying the extra amount.
LOXJIE D30 ($260)
By opting for the Loxjie D30, you will be investing an additional $60 to acquire a DAC chip (ES9068AS) with superior specifications and MQA support. While the D30 primarily functions as a DAC/pre, it falls short in terms of headphone amplification when compared to the K5 Pro ESS, as it is underpowered and lacks excellence. However, it compensates for this by offering Bluetooth with aptX HD and a remote control, along with the exclusive ability to have a fixed level line output and function as a standalone DAC. In terms of sound quality, there is a marginal improvement in refinement, technicality, clarity, and definition. It is crucial to carefully assess your requirements before making a decision.
In the end
There is not much more to mention about the K5 Pro ESS. It is an upgraded edition of the popular FiiO product, which justifies its price completely. With exceptional sound performance and excellent build quality, it stands as one of the finest and versatile, entry-level DAC/amps available in the market.
Copyright – Petros Laskis 2022.
+ Versatile all-in-one DAC/amp + Neutral and balanced + Powerful amplifier + Value for money + Analogue input and pre out + Three digital inputs + Silent and noise free + Better than the AKM version + Well made + Compact size
- Not the most resolving or refined - Could be a little more impactful - No Bluetooth input - Strong competition - Not compatible with the FiiO control application
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