FiiO K17 Desktop DAC & Headphone Amplifier

Exploring new frontiers Symphony of retro elegance and modern technology
This is the next generation desktop decoding headphone amplifier, aiming to be a unique and excellent performer. It is a symphony of retro elegance and cutting-edge technology, featuring a unique design and rich functionality all wrapped in a powerful package. The FIIO K17 is not only the upgraded successor to the K9 Pro, it is also an exploration of new possibilities for a high-end desktop DAC and headphone amplifier.

A mixing console for desktop HiFi
Specialty chips for specialty uses Exceptionally strong
The K17 features an M21586Q DSP chip which is capable of double- precision 64-bit floating-point calculations, and runs at a high 360MHz clock frequency. This chip is complemented by a high-performance ES9821Q ADC as well as a specially customized ultra-low phase noise femtosecond crystal oscillator. These three components allow the user, in all modes, to utilize the 31-band high-precision lossless PEQ. The PEQ is designed to ensure the audio signal is still of high fidelity even after being processed. The chip also allows for robust output protection functionality, ensuring that headphones and other connected audio equipment are fully protected.

31-band high-precision lossless PEQ
DEL (Dual Engine Limiter) technology together with proprietary algorithms allows the K17’s PEQ to be capable of dynamic range compression(DRC)/ dynamic range expansion (DRE), limiter, and compressor adjustment functions. PCM 44.1k~96k signals can be processed in the PEQ without sample rate conversion. Fine adjustments of audio parameters are thus possible, allowing for adjustments such as a gain range of +12~-24dB and a Q value range of 0.4dB~128dB. The PEQ allows the user to simulate or correct the frequency response curve PEQ settings can be easily exported, imported, shared, and saved - making it easy for anybody to use the PEQ and correct or simulate various frequency response curves of different headphones.

Discrete class AB transistor current amplification headphone amplifier
An important part of the K17 is a carefully crafted fully discrete amplifier circuit for headphones. This discrete circuit is of an OP+ transistor current amplification design, equipped with the classic pair of ON Semiconductor MJE243/253 transistors. It is capable of producing high current with low output impedance. The result is up to 4000mW+4000mW output power in balanced mode, nearly double that of the K9 Pro ESS. This allows it to easily drive various kinds of headphones and IEMs and to produce smooth, pleasant, and natural sound.

AKM flagship DAC AK4191+AK4499EX*2
In the K17 is the flagship AKM DAC chip combination - AK4191+AK4499EX*2. Two AK4499EX chips handle each channel. The 8-channel to 4-channel LPF design reduces common mode interference, resulting in better channel separation and dynamics. It also features a newly designed architecture with fully separated digital/analog portions, which also incorporates the newly developed “DWA ROUTING” technology for an even cleaner audio background and improved resolution.

Physically separated boards
The various sections of the internal power supply, digital, and analog sections are all located on physically separated circuit boards to avoid interference between them. This ensures the accuracy and integrity of signal processing for purer, cleaner audio output.

Precision power supply design
35W low-noise linear power supply Five large 4700μF electrolytic capacitors
Powering the K17 is a custom high-quality low-noise transformer, ensuring the purity of the power supplied. Additionally, five 4700μF electrolytic capacitors provide ample power reserves to ensure a steady supply of power.

3 ACCUSILICON low phase noise femtosecond audio crystal oscillators
The K17 employs three industry-leading ACCUSILICON ultra-low phase noise femtosecond crystal oscillators, including the AS318-L (45.1584MHz, 49.1520MHz) and AS318-Pro (24.576MHz). These significantly reduce the impact of phase noise on audio signals, allowing audio signals of various sampling rates to be precisely and faithfully restored – resulting in purer and more consistent sound.

Dual-core design Smooth stable experience
High-performance X2000 multi-core processor: The processor features a unique design consisting of a main XBurst@2 CPU core with two logic CPUs plus an XBurst@ small core. This chip offers excellent computing power with low power consumption. The X200 ensures precise audio signal processing and stable, smooth audio playback. Low-power ESP32-S3 SoC: Within this chip is a high-performance Xtensa 32-bit LX7 dual-core processor capable of running up to 240MHz as well as an ultra-low power consumption co-processor. This SoC allows the K17 to provide a fast and smooth user experience.