FiiO K17 R2R Desktop DAC and Headphone Amplifier - Silver

The FiiO K17 R2R is a desktop DAC, headphone amplifier, preamplifier and network streamer in one chassis, built for anyone who wants a single box to drive serious headphones from a computer, a NAS, Roon or AirPlay. It takes the K17 platform and replaces its delta-sigma chips with FiiO's own discrete R2R PRO resistor-ladder DAC, giving a warmer, more natural presentation while keeping the 4,000mW balanced amplifier, 31-band parametric EQ and full streaming stack. It is available in black with black walnut side panels or silver with ash; this is the silver version.

Proprietary R2R PRO Resistor-Ladder DAC

Conversion is handled by a FiiO-designed 24+5-bit segmented R2R PRO resistor array. The upper five bits are decoded by 31 thermometer-coded resistors, which addresses the error accumulation of conventional R2R ladders and lowers distortion. The result is the character R2R listeners look for: clear yet smooth, natural and warm, with a choice of NOS (non-oversampling) or OS (oversampling) modes to fine-tune the timbre. An XMOS XU316 USB interface accepts PCM up to 32-bit/768kHz and native DSD256, and the signal path is clocked by two ACCUSILICON AS318-L ultra-low phase noise femtosecond oscillators plus a FiiO-customised 12MHz oscillator. From the DAC through I/V conversion and low-pass filtering to the headphone stage, the whole audio circuit is fully differential, using multiple low-noise Texas Instruments op-amps.

Discrete Class AB Headphone Amplifier

The headphone amplifier is a fully discrete op-amp plus transistor current-amplification design using the classic ON Semiconductor MJE243/MJE253 pair. It delivers up to 4,000mW per channel from the balanced outputs into 32 ohms (1,850mW single-ended), nearly double the output of the K9 Pro ESS, with 950mW per channel balanced into 300 ohms for demanding planar and high-impedance headphones. Measured performance is strong: THD+N below 0.0052%, a signal-to-noise ratio of at least 125dB (A-weighted) and a noise floor under 2.6μV, a clear improvement on the original K17. Five gain settings suit everything from sensitive in-ear monitors to full-size headphones, and the unit protects itself against headphone amp and transformer over-temperature, output overload, output DC and power input overcurrent.

31-Band Lossless PEQ with AUTO EQ

A M21586Q DSP running 64-bit floating-point calculations at 360MHz, paired with an ES9821Q ADC, provides a 31-band high-precision lossless parametric EQ that works in every input mode, including the analogue inputs. PCM signals from 44.1kHz to 96kHz are processed without sample-rate conversion, gain is adjustable from +12dB to -24dB, and FiiO's DEL (Dual Engine Limiter) technology adds dynamic range compression and expansion, limiter and compressor functions. AUTO EQ matches your headphones to a target curve in one tap, there are built-in presets for Pop, Jazz and Classical, and profiles can be exported, imported and shared.

Streaming, Local Playback and Connectivity

With Roon Ready, AirPlay and Qplay certification the K17 R2R slots into the platforms you already use, and NAS playback over NFS and SMB brings a whole home music library into reach through the FIIO Control app. Gigabit Ethernet and an AP6256 dual-band Wi-Fi module (2.4GHz and 5GHz) handle the network, while Bluetooth 5.1 via a Qualcomm QCC5125 receives SBC, aptX, aptX LL, aptX HD, aptX Adaptive and LDAC. A rear USB-A port plays music from a flash drive or portable hard drive at up to 384kHz/32-bit and DSD256. The front panel carries 6.35mm, 4.4mm balanced and 4-pin XLR balanced headphone outputs plus a USB-C input for a quick connection; the rear adds a USB-C input, optical and coaxial inputs and outputs, 4.4mm balanced and RCA line inputs, RCA and XLR balanced line outputs for preamp or pure DAC duties, a 12V trigger input, an RS232 port for EQ configuration from a computer and a ground-lift switch to cure hum when the unit is connected to other equipment.

Power Supply and Build

Power comes from a 35W low-noise linear supply with a custom transformer and five 4,700μF electrolytic capacitors, with separate feeds for the digital and analogue sections and multi-stage regulation from low-noise, high-PSRR LDO regulators. The power, digital and analogue circuits sit on physically separated boards, and the parts list includes Rubycon solid capacitors, Nichicon, ELNA SILMIC II, ELNA RA3 and WIMA audio capacitors, silver-plated oxygen-free copper internal wiring and gold-plated NEUTRIK connectors. The square-and-round K17 design gains solid North American hardwood side panels, so the grain of every unit is unique, while a 3.93-inch touchscreen, five control knobs and an aluminium alloy infrared remote handle day-to-day use. An X2000 multi-core processor paired with a low-power ESP32-S3 SoC keeps the interface fast and smooth. Supplied with an AC power cord, remote control, two USB data cables, a headphone plug adaptor, XLR4 dust plug and a spare fuse.