FiiO K17 silver

The aluminium construction and retro design of the FiiO K17 immediately catch the eye, but what truly sets it apart is the advanced technology inside. The FiiO K17 headphone amplifier is designed for demanding headphone enthusiasts, and its Class AB power stage easily handles even the most demanding headphones, while the high-performance dual DAC provides exceptional clarity and precision. The K17 can also function as a preamplifier when needed, and thanks to a wide range of digital and analogue connections, including balanced headphone outputs, it offers impressive flexibility along with wireless streaming via AirPlay, Bluetooth, and Roon. Control is intuitive and enjoyable thanks to a combination of retro rotary knobs and a modern touchscreen, making every listening session not only fun but also sonically enriching.

Advanced audio processing and fully differential design

The K17 is equipped with a 31-band high-precision PEQ thanks to the M21586Q DSP chip and an ultra-low-phase femtosecond oscillator. The AKM AK4191 and AK4499EX ×2 DAC chips, along with fully separate digital and analogue sections and DWA ROUTING technology, ensure a clean sound background, excellent channel separation, and high resolution. The entire audio circuit is fully differential, with low-noise OPA1612 operational amplifiers, which delivers a high dynamic range and minimises crosstalk.

Discrete headphone amplifier with class AB transistors

An important part of the K17 is its meticulously designed fully discrete headphone amplifier circuit. The discrete circuit is an OP+ transistor current amplification design, equipped with a classic pair of ON Semiconductor MJE243/253 transistors. It is capable of providing high current with low output impedance. The result is up to 4000mW + 4000mW of output power in balanced mode, which is almost double that of the K9 Pro ESS. It makes it easy to drive various types of headphones and IEMs and creates a smooth, pleasant, and natural sound.

Fully differential audio architecture with separate circuits for maximum signal purity

From DAC through I/V conversion to low-pass filtering and the headphone amplifier, the entire audio circuit is designed with a fully differential architecture. This ensures both a high dynamic range for the signal and significantly reduced crosstalk between channels. Various parts of the audio circuit, including the I/V conversion and LPF stages, use multiple low-noise precision OPA1612 operational amplifiers to ensure dynamic audio output. The different parts of the internal power supply, the digital and analogue sections, are placed on physically separate circuit boards to prevent interference between them. This ensures the accuracy and integrity of the signal processing for a cleaner, higher-quality audio output.

Stable power supply and premium components

The power supply for the analogue and digital sections is separate, supported by a high-quality low-noise transformer and five large 4700µF capacitors for stable performance. Three ultra-low-phase ACCUSILICON oscillators ensure accurate sound reproduction and minimise the effect of phase noise. Premium components: Panasonic film capacitors, ELNA SILMIC II, Nichicon audio capacitors, and silver-plated conductors guarantee low noise, stability, and signal fidelity in every part of the device.

Perfect sound starts with a precise power supply

Separate power supplies for the digital and analogue circuits effectively prevent crosstalk and mutual interference. The K17's analogue audio circuit is powered by a multi-stage power supply. Many of these stages have a dedicated power management circuit, including stages for digital-to-analogue conversion, LPF, and transistors. The low-noise TPA7A47/7A33 LDO regulators with a high power supply ripple rejection ratio (PSRR) also function as secondary voltage regulators to continuously ensure stable and clean power.

3 femtosecond low-phase-noise ACCUSILICON audio crystal oscillators

The K17 uses three top-of-the-line femtosecond crystal oscillators ACCUSILICON with ultra-low phase noise, including the AS318-L (45.1584MHz, 49.1520MHz) and AS318-Pro (24.576MHz) models. They significantly reduce the effect of phase noise on audio signals, which allows for accurate and faithful reproduction of audio signals at different sampling rates – the result is cleaner and more consistent sound. 

Dual-core design for a smooth and stable experience

The high-performance multi-core X2000 processor, which features a unique design consisting of a main XBurst 2 CPU core with two logical CPUs and a small XBurst core. The chip offers excellent computing performance with low power consumption. The X2000 ensures precise audio signal processing and stable, smooth audio playback. Low-power SoC ESP32-S3: This chip includes a high-performance 32-bit dual-core Xtensa LX7 processor capable of running at up to 240MHz, as well as an ultra-low-power coprocessor. The SoC enables the K17 to provide a fast and smooth user experience.

Harmonious design with intelligent protection

The design cleverly combines a square and a circle into a harmonious whole, combining retro elegance with a modern technological aura for a refreshing experience. Both functionality and design have been carefully considered, exemplified by the presence of multiple controls for easier operation and a grid structure for faster heat dissipation. Listen with peace of mind thanks to various protection mechanisms that can intelligently detect abnormal conditions and trigger automatic protection to prevent damage to the device. The system includes thermal protection for the headphone amplifier, thermal protection for the transformer, output overload protection, DC output protection, and power input overcurrent protection.